Literature DB >> 26798284

Systematics of Nothopsini (Serpentes, Dipsadidae), with a new species of Synophis from the Pacific Andean slopes of southwestern Ecuador.

R Alexander Pyron1, Juan M Guayasamin2, Nicolás Peñafiel2, Lucas Bustamante3, Alejandro Arteaga3.   

Abstract

Within Dipsadinae, some recent authors have recognized a tribe Nothopsini containing the genera Diaphorolepis, Emmochliophis, Nothopsis, Synophis, and Xenopholis, on the basis of a number of putative morphological synapomorphies. However, molecular results suggest that Nothopsis, Synophis, and Xenopholis do not form a monophyletic group, while the remaining taxa are unsampled in recent molecular phylogenies. Here, DNA-sequence data for some Diaphorolepis and Synophis species are provided for the first time, as well as additional new sequences for Nothopsis and some Synophis species. Including these and other existing data for nothopsine species, previous studies showing that Nothopsini is not a natural group are corroborated. Nothopsini Cope, 1871 is restricted to Nothopsis. Diaphorolepidini Jenner, 1981 is resurrected and re-delimited to include only Diaphorolepis, Emmochliophis, and Synophis. Finally, Xenopholis remains Dipsadinae incertae sedis. Known material of Diaphorolepidini is reviewed to generate revised and expanded descriptions and diagnoses at the tribe, genus, and species level. Numerous cryptic species are likely present in Synophis bicolor and Synophis lasallei. Finally, a new population from the low-elevation cloud forests of SW Ecuador is reported upon, which is genetically and morphologically distinct from all other species, that is here named Synophis zaheri sp. n.

Entities:  

Keywords:  Diaphorolepis; Dipsadinae; Nothopsini; Serpentes; Synophis

Year:  2015        PMID: 26798284      PMCID: PMC4714381          DOI: 10.3897/zookeys.541.6058

Source DB:  PubMed          Journal:  Zookeys        ISSN: 1313-2970            Impact factor:   1.546


Introduction

Within (sensu Pyron et al. 2013), , , , , and were historically thought to form a monophyletic group on the basis of scutellation, osteological, histological, hemipenial, and respiratory characters (see Sheil and Grant 2001). The group has been referred to as tribe by some authors (Savitzky 1974; Dowling and Duellman 1978). The genera , , and have also been referred to this assemblage (Wallach 1995). Alternatively, Jenner (1981) proposed a tribe containing along with , , , , , , , , and , while was placed in , and was not accounted for. Most subsequent studies have considered to contain only , , , , and (see Sheil and Grant 2001; Martinez 2011). Some of these taxa, in particular, bear a strong external resemblance to Asian xenodermatids such as (Bogert 1964). In contrast, molecular phylogenetic analyses have strongly supported (Vidal et al. 2010), (Sheehy 2012), and (Vidal et al. 2010; Pyron et al. 2011; Grazziotin et al. 2012) as dipsadines, as does hemipenial morphology (Zaher 1999). However, these genera do not form a monophyletic group within in molecular phylogenies, and are widely separated in different dipsadine clades (Vidal et al. 2010; Grazziotin et al. 2012; Sheehy 2012; Pyron et al. 2013). Thus, the tribe does not appear to represent a natural group, despite the putative morphological synapomorphies uniting the taxa listed above (Savitzky 1974; Ferrarezzi 1994; Wallach 1995; Martinez 2011). Contrastingly, the strength of the molecular results suggests that these likely represent convergence, at least between and . This is not surprising, given the massive ecomorphological diversification exhibited by following their adaptive radiation in the Neotropics (Cadle 1984a, b, c). However, and have still not been sampled in any molecular phylogeny, and it is thus unclear where their phylogenetic affinities lie. Morphological evidence suggests that these two genera form a clade with (see Hillis 1990). Furthermore, there are multiple species of , with potentially unclear species boundaries (Bogert 1964; Fritts and Smith 1969; Sheil 1998; Sheil and Grant 2001). Here, we report on new material from , , and , present a new molecular phylogeny, and describe a new species of . We review current knowledge of , , and , and discuss species limits in these genera. Dipsadine diversity in the Andes is clearly underestimated, and new species are still being discovered in the 21st century (e.g., Salazar-Venezuela et al. 2014; Sheehy et al. 2014; Zaher et al. 2014).

Materials

Molecular phylogeny

Work in Ecuador was carried out under permit number MAE-DNB-CM-2015-0017. We obtained tissue samples of (3 specimens), (3), (1), (1), a new species (2), and (1), via fieldwork in Ecuador. The specimens are deposited at the ; Tables 1, 2). We also obtained a tissue loan of the holotype of from Ecuador (KU 197107; Hillis 1990) from the University of Texas at Austin.
Table 1.

Morphometric data for specimens of species examined or from literature. Codes are: MT; IL; SL; PO; V; SC; D1-3; SVL; TL. Museum codes are given in Sabaj-Perez (2013). Includes data from ReptiliaWebEcuador (Torres-Carvajal et al. 2014).

=maxillary teeth

=infralabials

=supralabials

=postoculars

=ventrals

=subcaudals

=dorsal scale rows at neck, midbody, and vent

=snout-vent length (mm)

=tail length (mm)

SpeciesCollectionMTILSLPOVSCD1D2D3SVLTLSex
Diaphorolepis laevisNMW 1486016108/9215784191917350145-
Diaphorolepis wagneriAMNH 49179231083194138211917290153M
Diaphorolepis wagneriGML 4-00014251092197133211917355187F
Diaphorolepis wagneriKU 75682241092196136211917311142F
Diaphorolepis wagneriMECN 2937--93181133191917276129M
Diaphorolepis wagneriMZUTI 3322-1182189141191917332167F
Diaphorolepis wagneriMZUTI 3752-1181189134211917447257M
Diaphorolepis wagneriMZUTI 3901-1393195131191917524259F
Diaphorolepis wagneriNMW 18915-1392191137211917307146M
Diaphorolepis wagneriZSM 2708/025129219398211917484200F
Emmochliophis fugleriUIMNH 787951688214097191919--M
Emmochliophis miopsBMNH 1946.1.12.301388114593191919251134F
Eastern Andes
Synophis aff. bicolorFHGO 9186-1192164105191717379184M
Synophis aff. bicolorMZUTI 3529-1182163106191917407202M
Synophis aff. bicolorMZUTI 4180-1192152100191918457214M
Synophis aff. bicolorUMMZ 9155024/271192160103-1917529235F
Synophis aff. bicolorUMMZ 91551--82161105-1917535230F
Synophis aff. bicolorUMMZ 91552--82166106-191715361F
Western Andes
Synophis aff. bicolorBMNH 1940.2.30.31--82162118211917408241M
Synophis aff. bicolorCAS 23612--82166100-191718680F
Synophis aff. bicolorMCZ R-164530-1192164116-1917367208-
Synophis aff. bicolorQCAZ 10453-1182--------
Synophis aff. bicolorTCWC 66209-118216096211917---
Synophis aff. bicolorUMMZ 185812-1082165105-191714466-
Synophis aff. bicolorUMMZ 185813-1082162122---257147-
Synophis cf. bicolorMHUA 14133>231282193127-19---M
Synophis cf. bicolorMHUA 14577241182190131191917---
Synophis cf. bicolorMLS2072-11/1082184127-1917407210M
Synophis bicolorMECN 6732-982174138191717361236M
Synophis bicolorMECN 6733-982174132191917406245M
Synophis bicolorMECN 8076-982183135191717376233M
Synophis bicolorMZUT 25716982180136-1917---
Synophis bicolorMZUTI 4175-1182174143191917365245M
Synophis bicolorUTA R-55956-982176129-1917---
Synophis calamitusKU 164208-98116312521191714273-
Synophis calamitusKU 197107-97116611021191714974F
Synophis calamitusMZUTI 3694-1192166118231917462265M
Synophis calamitusQCAZ 11931-981--------
Synophis lasalleiFMNH 8131324--2154112-21-292158F
Synophis lasalleiEPN S.974---2156116-21-17590M
Synophis lasalleiEPN S.97524--2155119-21-354201M
Synophis lasalleiFHGO 6489-118214711123212115386M
Synophis lasalleiFHGO 8340-118215388211917415199M
Synophis lasalleiMCZ R-156873-1171147115---412206-
Synophis lasalleiMECN 11250-108215398211917412196F
Synophis lasalleiMECN 11262--82154118212117306145M
Synophis lasalleiMECN 2220-1082165117191917294146M
Synophis lasalleiMLS/CJSP---2144101---300170M
Synophis lasalleiMZUTI 4181-11921562921211927242M
Synophis lasalleiUSNM 233061-1192156124-21-285160M
Synophis lasalleiUSNM 233062-1182153126-2220360200-
Synophis lasalleiUSNM 233063-118215186232119308197M
Synophis lasalleiUSNM 233064-1182151--2119270150-
Synophis plectovertebralisUVC 11580-88114491191917212100M
Synophis plectovertebralisUVC 11858-7711477919191719676.5F
Synophis zaheriMZUTI 3353-882166112191917351184M
Synophis zaheriMZUTI 3355-982169111191917372194M
Table 2.

Vouchered localities for specimens of species examined or from literature. In general, localities are given verbatim as transcribed from the literature, museum records, or field notes. Co-ordinates represent georeferencing attempts from gazetteers under standard guidelines, though some variation from the exact collecting locality will inevitably be present. Similarly, elevations are taken from Google Earth, and may not exactly match the elevations as originally reported. Museum codes are given in Sabaj-Perez (2013). Includes data from ReptiliaWebEcuador (Torres-Carvajal et al. 2014).

SpeciesCollection NumberLocalityLatitudeLongitudeElev.
Diaphorolepis wagneriGML 4-00014Panama Darien, Cerro Mali, in Serrania del Darien8.128557-77.2534981268
Diaphorolepis wagneriMECN 2937Canandé, Ecuador0.529930-79.035410596
Diaphorolepis wagneriMZUTI 3322Milpe, Ecuador0.034890-78.8671301076
Diaphorolepis wagneriMZUTI 3901Mashpi Lodge, Ecuador0.164030-78.8707301068
Diaphorolepis wagneriNMW 18915El Palmar, Canar, Ecuador-2.533300-79.333300325
Diaphorolepis wagneriQCAZ 380Ecuador, Cotopaxi, Las Pampas-0.348360-79.0760101238
Diaphorolepis wagneriQCAZ 381Ecuador, Pichincha, Tandapi-0.415220-78.7972801457
Diaphorolepis wagneriQCAZ 8450Ecuador, Cotopaxi, Pucayacu–Sigchos-0.702730-79.056810974
Diaphorolepis wagneriQCAZ 8782Imbabura Lita, Ecuador0.815270-78.388350865
Diaphorolepis wagneriUVC 1218718km East of San Jose de Palmar, Colombia4.966667-76.2333331546
Diaphorolepis wagneriUVC 5254Colombia, Cali, Pichinde, Farallones de Cali3.433400-76.6166801614
Diaphorolepis wagneriUVC 5255Colombia, Pance, Camino a Corea, Pance, Farallones de Cali3.328340-76.6386501632
Emmochliophis fugleriUIMNH 787954 km. E Río Baba Bridge, 24 km. S Santo Domingo de los Colorados, Pichincha, Ecuador-0.435562-79.246212618
Emmochliophis miopsBMNH 1946.1.12.30Parambas (Imbabura), Ecuador0.805000-78.3508331105
Eastern Andes
Synophis aff. bicolorFHGO 9186Río Zopladora, Ecuador-2.611510-78.4721741677
Synophis aff. bicolorKU 121341Ecuador, Pastaza, Mera-1.457452-78.1079761111
Synophis aff. bicolorMZUTI 3529Wild Sumaco, Ecuador-0.675700-77.6012901463
Synophis aff. bicolorMZUTI 4180El Genairo, Ecuador-4.166181-78.940941212
Synophis aff. bicolorUMMZ 91550Ecuador, Napo-Pastaza, Abitagua-1.383000-78.0830001482
Western Andes
Synophis aff. bicolorBMNH 1940.2.30.31Río Solaya, Ecuador-0.010213-78.8195101008
Synophis aff. bicolorCAS 23612Chimborazo, Naranjapata, Ecuador-2.266667-79.083333763
Synophis aff. bicolorMCZ R-164530Ecuador, Pichincha, Tandapi-0.419803-78.8011321714
Synophis aff. bicolorQCAZ 10453Cotopaxi: Naranjito, Bosque Integral Otonga-0.417820-78.9880301655
Synophis aff. bicolorTCWC 66209Ecuador, Cotopaxi, Las Pampas-0.348360-79.0760101238
Synophis aff. bicolorUMMZ 185812Ecuador, Cotopaxi, San Francisco de Las Pampas-0.440357-78.9666291586
Synophis cf. bicolorMHUA 14577Colombia, Dpto. Antioquia, Mpio. Amalfi, V. da La Manguita, Fca. La Esperanza6.978611-75.0444441394
Synophis cf. bicolorMLS 2072Medellin, Cordillera Central, Colombia6.230833-75.5905561497
Synophis bicolorMECN 6732Tobar Donoso, Ecuador1.189930-78.504130229
Synophis bicolorMECN 6733Sendero Awa, Ecuador1.164400-78.507120257
Synophis bicolorMZUTI 4175Itapoa, Ecuador0.46411-79.15547267
Synophis bicolorUTA R-55956Ecuador, Esmeraldas, Canton San Lorenzo1.03212-78.613780318
Synophis calamitusKU 1642089 km SE Tandayapa, Pichincha Province, Ecuador-0.047404-78.6328042169
Synophis calamitusKU 1971074 km SE Tandayapa, Pichincha Province, Ecuador-0.012514-78.6506971889
Synophis calamitusMZUTI 3694Tambo Tanda, Ecuador-0.020108-78.6510122048
Synophis lasalleiEPN S.974Ecuador, Napo-Pastaza, nr. Río Talin, headwaters of the Río Bobonaza-1.466670-77.883300948
Synophis lasalleiFHGO 6489Ceploa, Ecuador-1.339063-77.670660839
Synophis lasalleiFHGO 7770Cara del Indio, Ecuador-3.575695-78.4510201207
Synophis lasalleiFHGO 8340El Quimi, Ecuador-3.571852-78.516598752
Synophis lasalleiFMNH 81313Colombia, Meta, Pico Renjifo, Serrania de la Macarena2.476901-73.794852520
Synophis lasalleiKU 1642212 km SSW Río Reventador, Ecuador-0.100000-77.6000001479
Synophis lasalleiMCZ R-156873Ecuador, Napo Prov., Inecel Station, Cascada San Rafael, Río Quijos-0.103401-77.5854871290
Synophis lasalleiMECN 11250Paquisha Alto, Ecuador-3.909518-78.4872441660
Synophis lasalleiMECN 11262El Pangui, Ecuador-3.624502-78.586510814
Synophis lasalleiMECN 2220Puyo, Ecuador-1.466780-77.983350957
Synophis lasalleiMLS/CJSPN of Alban, cen. Cundinamarca Dept., cen. Colombia4.883333-74.4500001983
Synophis lasalleiMZUTI 4181Sacha Yaku, Ecuador-1.407882-77.711092974
Synophis lasalleiUSNM 233061Río Arajuno, headwaters of, tributary of Río Napo, Pastaza, Ecuador-1.400000-77.883300969
Synophis lasalleiUSNM 233062Río Siquino, tributary of Río Villano, Upper Curaray, Pastaza, Ecuador-1.455303-77.714685576
Synophis lasalleiUSNM 233063Río Bobonaza, headwaters of, Ecuador-1.512156-77.833454594
Synophis lasalleiWWL 977-978Colombia, Meta prov., Villavicencio4.150000-73.633333539
Synophis plectovertebralisUVC 11580Haciendo San Pedro, 6km S El Queremal, Municipio Dagua, Valle del Cauca, Colombia3.483333-76.7000001830
Synophis zaheriMZUTI 3353Buenaventura Lodge, Ecuador-3.647970-79.755070874
Synophis zaheriMZUTI 3355Buenaventura Lodge, Ecuador-3.648820-79.756400812
Museo de Zoología at the Universidad Tecnológica Indoamérica Morphometric data for specimens of species examined or from literature. Codes are: MT; IL; SL; PO; V; SC; D1-3; SVL; TL. Museum codes are given in Sabaj-Perez (2013). Includes data from ReptiliaWebEcuador (Torres-Carvajal et al. 2014). =maxillary teeth =infralabials =supralabials =postoculars =ventrals =subcaudals =dorsal scale rows at neck, midbody, and vent =snout-vent length (mm) =tail length (mm) We isolated total DNA from liver tissue or tail tips by proteinase K digestion in lysis buffer, followed by protein precipitation with guanidine thiocyanate solution and final DNA precipitation using isopropyl alcohol. We used the following pairs of primers to amplify and sequence four mitochondrial genes (12S, 16S, CYTB, ND4) and one nuclear locus (CMOS): Snake_12S_F (5’-AAACTGGGATTAGATACCCCACTAT-3’), Snake_12S_R (5’-GTRCGCTTACCWTGTTACGACT-3’), Snake_16S_F (5’-CGCCTGTTTAYCAAAAACAT-3’), and Snake_16S_R (5’-CCGGTCTGAACTCAGATCACGT-3’) from Kessing et al. (1989); Snake_Cytb_F (5’-GACCTGTGATMTGAAAACCAYCGTTGT-3’) and Snake_Cytb_R (5’-CTTTGGTTTACAAGAACAATGCTTTA-3’) from Burbrink et al. (2000); Snake_ND4_F (5’-CACCTATGACTACCAAAAGCTCATGTAGAAGC-3’) and Snake_ND4_R (5’-CATTACTTTTACTTGGATTTGCACCA-3’) from Arévalo et al. (1994); and Snake_cmosFs77 (5’-CATGGACTGGGATCAGTTATG-3’) and Snake_cmosRs78 (5’-CCTTGGGTGTGATTTTCTCACCT-3’) from Lawson et al. (2005). We set up PCR reactions to a total volume of 25 µL containing MgCl2 2–3 mM, dNTPs 200 µM, 0.2 µM of each primer (0.8 µM in the case of ND4) and 1.25 U (16S and Cytb) or 0.625 U (ND4 and c-mos) of Taq DNA polymerase (Invitrogen). Thermocycling parameters consisted of an initial three-minute step at 94 °C; 25 to 30 cycles of 45–60 sec at 94 °C, 45 (16S and c-mos) or 60 (ND4 and Cytb) sec at 53–60 °C, 1 (16S and c-mos) or 2 (ND4 and Cytb) min at 72 °C; and a final extension of 7 min at 72 °C. We used 1.5% agarose gels to visualize the PCR products and QIAquick PCR purification Kit (QIAGEN) to remove unincorporated primers and dNTPs from every PCR reaction before they were sent to Macrogen Inc. for sequencing. We combined these new data with the publically available sequences for and (Vidal et al. 2010; Grazziotin et al. 2012). We obtained additional sequences of from the Museu de Zoologia da Universidade de São Paulo (MHUA 14577 [Museo de Herpetología de la Universidad de Antioquia], from Colombia: 12S, 16S, CYTB, and CMOS) and the University of Texas, Arlington (UTA-R 55956 from Ecuador: CYTB and ND4). We then included all publically available dipsadine species sampled for these genes. This matrix contains 24% missing data (‘-’), but these have been shown not to have deleterious effects on taxon placement and support in previous analyses (e.g., Pyron ). Data were aligned using MAFFT (Katoh and Standley 2013) under the default parameters in Geneious 7.1.9 (Biomatters Ltd.). We determined the optimal partitioning strategy using PartitionFinder (Lanfear et al. 2012). We estimated the phylogeny using MrBayes 3.2.5 (Ronquist et al. 2012), with 4 runs of 4 chains each, run for 20 million generations with the first 25% discarded as burnin. Convergence was assumed as the average standard deviation of split frequencies went to zero and the potential scale reduction factors went to one (Ronquist et al. 2012). The GenBank accession numbers for the new and existing data are given in Appendix I.

Morphological data

Species in , , and have traditionally been delimited using easily determined external morphological characters (Bogert 1964; Hillis 1990). We relied here on a set of these characters, scored for museum specimens and our new material, to examine and delimit species boundaries (Table 1). For available specimens examined in person, in photographs, or in the literature, we recorded SVL and TL in mm, and counts of supralabials, infralabials, postoculars, ventrals, and subcaudals. We made cursory notes on the hemipenes of some male specimens when they were visible (Zaher 1999; Martinez 2011).

Results

The overall topology and support (Figs 1, 2) is similar to numerous recent studies (Zaher et al. 2009; Vidal et al. 2010; Pyron et al. 2011; Grazziotin et al. 2012). We consider strong support to be posterior probabilities ≥95%, following recent authors (Felsenstein 2004). Overall, there is low support for many backbone nodes, which may reflect inadequate sampling of taxa (only ~250 out of ~900 dipsadine species) or characters (only two independent loci).
Figure 1.

Phylogeny (part) of ~245 dipsadine species plus outgroups, based on partitioned, multi-gene Bayesian inference analysis of 3,462bp of mitochondrial and nuclear DNA. Support values given are posterior probabilities ≥50% from 15 million post-burnin generations.

Figure 2.

Phylogeny (part) of ~245 dipsadine species plus outgroups, based on partitioned, multi-gene Bayesian inference analysis of 3,462bp of mitochondrial and nuclear DNA. Support values given are posterior probabilities ≥50% from 15 million post-burnin generations.

Phylogeny (part) of ~245 dipsadine species plus outgroups, based on partitioned, multi-gene Bayesian inference analysis of 3,462bp of mitochondrial and nuclear DNA. Support values given are posterior probabilities ≥50% from 15 million post-burnin generations. Phylogeny (part) of ~245 dipsadine species plus outgroups, based on partitioned, multi-gene Bayesian inference analysis of 3,462bp of mitochondrial and nuclear DNA. Support values given are posterior probabilities ≥50% from 15 million post-burnin generations. Species in can be broadly grouped into a primarily North American clade ( to when viewing Fig. 1), a primarily Central American clade ( to in Fig. 1), and a primarily South American clade ( to in Fig. 2), though many species in the latter two clades range across both Central and South America. Several speciose genera in the primarily Central American clade are non-monophyletic, including , , , , , (Fig. 1), as in previous studies (Grazziotin et al. 2012; Pyron et al. 2013). In agreement with previous results (Grazziotin et al. 2012; Pyron et al. 2013), we find that is not a natural group (Fig. 1). The genus is strongly supported, and strongly placed with + within the Central American clade. Correspondingly, is strongly supported and weakly nested within the South American clade, as the sister lineage to . It appears that one (KU 222204) from a previous study (Pyron et al. 2011) may have been misidentified, and is actually related to . This specimen is strongly supported as the sister lineage to the sampled (R-6955), to the exclusion of the three other sampled , which are strongly supported as a monophyletic group. This specimen is from the Peruvian Amazon and is pictured in Duellman and Mendelson (1995). The specimen pictured resembles the Amazonian , rather than the more xeric from the Brazilian shield. Thus, it is possible either that a curatorial or laboratory error occurred at some point, or that there is cryptic genetic diversity in . A strongly-supported clade comprising and represents the sister to the large, primarily Central American clade that also contains . Monophyly of with respect to is weakly supported. Within a weakly paraphyletic , there are three deeply divergent lineages, and the sampled specimen of An apparently new species of is the strongly-supported sister lineage of . The species remains unsampled in the molecular phylogeny. Although is not sampled, we follow previous authors in assuming a close relationship with and , given their strong resemblance (Savitzky 1974; Hillis 1990). Thus, the synapomorphies previously used to diagnose (Savitzky 1974; Wallach 1995) apparently represent convergence in at least three distantly related dipsadine lineages.

Systematics

We seek here to only name clades associated that are strongly supported in our molecular phylogeny. Above the genus level, is not a natural group in any of its recent conformations. We place alone in Cope, 1871. We resurrect and re-delimit the tribe Jenner, 1981 to include only , , and . The genus is not strongly supported in any supra-generic group and remains incertae sedis in (see Grazziotin et al. 2012). Our molecular and morphological data (Tables 1–3; Figs 1, 2) also corroborate previous authors in finding that genus and species boundaries within are unclear and in need of revision (Sheil and Grant 2001). We here provide photographs and range maps of representative material (Figs 3–9). A number of issues are immediately apparent, and can be addressed with our results. We outline these below.
Table 3.

Summary of measured diagnostic characters (external meristic features) for diaphorolepidine species. These data are a summary of Table 1 (omitting some subcaudal scale counts from apparently truncated tails), and can be used to identify ambiguous specimens in the field or collections, and should be updated with new material in the future.

SpeciesMTILSLPOVSCD1D2D3
Diaphorolepis laevis16108–9215784191917
Diaphorolepis wagneri23–2510–138–91–3181–197131–14119–211917
Emmochliophis fugleri1688214097191919
Emmochliophis miops1388114593191919
Synophis aff. bicolor24–2710–118–92152–16696–12219–2117–1917–18
Synophis cf. bicolor23–2410–1282184–193127–131191917
Synophis bicolor169–1182174–183129–1431917–1917
Synophis calamitus9–117–91–2163–166110–12521–231917
Synophis lasallei2410–117–91–2144–165101–12619–2319–2217–21
Synophis plectovertebralis7–87–81144–14779–91191917
Synophis zaheri8–982166–169111–112191917
Figure 3.

Photographs of some diaphorolepidine species in life: a MZUTI 3353 b MZUTI 3355 c MZUTI 3694 d aff. MZUTI 3529 e uncat., and f MZUTI 3901.

Figure 9.

Photographs in preservation of some diaphorolepidine species. Upper: MZUTI 4175, Middle: MZUTI 4181, Lower: aff. MZUTI 4180.

Photographs of some diaphorolepidine species in life: a MZUTI 3353 b MZUTI 3355 c MZUTI 3694 d aff. MZUTI 3529 e uncat., and f MZUTI 3901. Photographs of some diaphorolepidine species in life: UTA R-55956 (a), and cf. MHUA 14577 (b). Map of vouchered localities for (yellow circles), (pink circles), (teal circles), (red circles), (green triangle) and (blue triangle). Map of vouchered localities for (teal squares). Map of vouchered localities for populations: sensu stricto (purple circles), western aff. (blue circles), eastern aff. (yellow circles), and cf. (teal circles). Photographs in preservation of some diaphorolepidine species. Upper: MZUTI 3901, Center: MZUTI 3355, Lower: MZUTI 3694. Photographs in preservation of some diaphorolepidine species. Upper: MZUTI 4175, Middle: MZUTI 4181, Lower: aff. MZUTI 4180. Vouchered localities for specimens of species examined or from literature. In general, localities are given verbatim as transcribed from the literature, museum records, or field notes. Co-ordinates represent georeferencing attempts from gazetteers under standard guidelines, though some variation from the exact collecting locality will inevitably be present. Similarly, elevations are taken from Google Earth, and may not exactly match the elevations as originally reported. Museum codes are given in Sabaj-Perez (2013). Includes data from ReptiliaWebEcuador (Torres-Carvajal et al. 2014). Summary of measured diagnostic characters (external meristic features) for diaphorolepidine species. These data are a summary of Table 1 (omitting some subcaudal scale counts from apparently truncated tails), and can be used to identify ambiguous specimens in the field or collections, and should be updated with new material in the future. First, the head scalation of has not been accurately characterized by most authors (see Bogert 1964). Additionally, the holotype of was incorrectly described with respect to several characters (Werner 1923). Finally, reviewing museum specimens, including most holotypes, reveals that the current species boundaries and diagnoses are oftentimes inaccurate with respect to the observed range of variation in the relevant characters. In particular, the holotype of does not match many populations typically referred to this species (Bogert 1964; Hillis 1990; Sheil and Grant 2001). In the case of , the postoculars can range from 1–3 (rather than 1–2), as illustrated by Bogert (1964), but not discussed explicitly. Werner (1901) apparently considered the small, lower postocular to be a subocular. Occasionally, the middle postocular will not be in contact with the brille, and resembles a temporal, behind the two remaining postoculars. As noted previously, the nasals are never divided, but only creased (Sheil and Grant 2001), contrary to reports from some previous authors (Bogert 1964; Hillis 1990). In the case of , Werner (1923) diagnosed the species as having fewer ventrals and subcaudals than , and smooth dorsal scales. Examination of the holotype ( 14860) reveals that it is indeed keeled, albeit weakly, throughout most of the midbody and posterior dorsal scale rows. This includes a bicarinate vertebral scale row that was previously considered to be diagnostic only of . The specimen appears to have a lighter-colored nuchal collar, though this may be a preservation artifact. The type locality within Colombia is unknown. In the case of , the holotype ( 257) has 180 ventrals, 136 subcaudals, and 9 infralabials, whereas sampled populations from the Andes of Ecuador typically have 152–166 ventrals, 96–122 subcaudals, and 10 or 11 infralabials. The locality of the holotype is unknown. Sampled populations from the Chocó of Ecuador match the holotype more closely, with 174–183 ventrals, 129–143 subcaudals, and 9–11 infralabials. The Chocóan populations typically occur at low to middle elevations (~200–300m), whereas Andean populations occur at higher elevations (~800–1700m). PageBreakPopulations from the northern western Andes of Colombia have 184–193 ventrals, 127–131 subcaudals, and 10–12 infralabials. These three populations (Chocóan, Colombian Andean, and Ecuadorean Andean; Figs 3D, 4), correspond to three deeply divergent genetic lineages within (Fig. 1). A full revision of this species complex is pending further molecular and morphological sampling. We refer to the Chocóan populations as , the Ecuadorean Andean populations as aff. , and the Colombian Andean populations as cf. (using aff. versus cf. somewhat arbitrarily) for the remainder of the paper. The group is also weakly paraphyletic with respect to the sampled specimen of , which is the sister lineage of the Ecuadorean Andean lineages. The specimen of (MZUTI 4181) strongly matches the other specimens examined (Table 1), and is thus not a mis-identified .
Figure 4.

Photographs of some diaphorolepidine species in life: UTA R-55956 (a), and cf. MHUA 14577 (b).

Finally, we report here on two specimens of aff. from low to middle elevations on the Pacific versant of the Andes in SW Ecuador. These are diagnosable from the species above based on numerous characters, and we here name them:

sp. n.

http://zoobank.org/AEE122E3-497B-4DBF-8A2B-79DDD231E42B Figs 3 , 5 , 8
Figure 5.

Map of vouchered localities for (yellow circles), (pink circles), (teal circles), (red circles), (green triangle) and (blue triangle).

Figure 8.

Photographs in preservation of some diaphorolepidine species. Upper: MZUTI 3901, Center: MZUTI 3355, Lower: MZUTI 3694.

Holotype.

MZUTI 3353 (Fig. 3A), an adult male collected on 30 December 2013 at ~2200h by Alejandro Arteaga, Lucas Bustamante, Rita Hidalgo, Daniel Mideros, and Diana Troya, in the vicinity of Buenaventura Reserve (Fundación Jocotoco), near Piñas, El Oro Province, SW Ecuador, 874m above sea level (-3.65, -79.76; Fig. 5), in a narrow band of cloud forest on the Pacific versant of the Andes.

Paratype.

MZUTI 3355 (Fig. 3B), adult male collected a few minutes after the holotype, a few meters away.

Etymology.

Named after the preeminent Brazilian herpetologist Hussam El-Dine Zaher, for his innumerable contributions to South American herpetology and snake systematics.

Diagnosis.

can be differentiated from by an unmodified vertebral scale row with a single weak keel (versus a laterally expanded vertebral scale row, bicarinate or smooth); from by the presence of a loreal (versus absence); from by having 166–169 ventrals (versus 174–183) and 111–112 subcaudals (versus 129–143); from aff. by having 8 or 9 infralabials (versus 10 or 11) and lighter brown dorsal coloration in life (versus darker black); from cf. by having 166–169 ventrals (versus 184–193), 111–112 subcaudals (versus 127–131), and 8 or 9 infralabials (versus 10–12); from by having two postoculars (versus one typically) and internasals in contact (versus divided typically); from by having 166–169 ventrals (versus 144–165), 19 dorsal scale rows at midbody (versus 21–23 typically), 8 or 9 infralabials (versus 10 or 11), and by having the anteriormost dorsal scale rows smooth (versus keeled); and from by absence of a nuchal collar (versus presence) and two postoculars (versus one).

Description.

Small-sized snakes (351–372mm SVL, 184–194mm TL) with slender bodies and head distinct from neck. Eye large (>1/3 head height), bulbous, and black in life, with pupil not easily distinguishable from iris. Pupil round in preservative (though this may be an effect of fixation). Dorsum coloration grayish-brown with iridescent sheen in life and preservation, no light-colored nuchal collar in adults, and posterior supralabials mostly pigmented (>50%). Ventral coloration primarily bright yellowish-white, extending onto margins of ventral scales and supralabials. Posterior one-third of ventral surface anterior to vent becomes increasingly mottled, and ventral surface of tail color of dorsum. Squamation pattern includes 166–169 ventral scales, 111–112 subcaudals, 19-19-17 dorsal scale rows (scale-row reduction of 2 rows past midbody), anal single, no apical pits, mid-body dorsal scales with weak single keel (first few dorsal scale-rows smooth), vertebral scale row not enlarged, nuchal scales smooth, 8 supralabials, 8 or 9 infralabials, 2 postoculars, loreal present, nasal undivided, fused prefrontals, internasals in contact, and rostral concave. Condition of the vertebrae, which are heavily modified in and (Fritts and Smith 1969; Savitzky 1974; Hillis 1990) unknown, pending skeletal preparation or micro-CT scanning. Everted hemipenes are slightly bilobed, semicalyculate, and semicapitate, relatively stout and bulbous, covered in large spines or hooks, similar to that of and aff. and (Bogert 1964; Zaher 1999; Martinez 2011). Both specimens were active by night in primary evergreen foothill forest, with canopy cover between 70 and 100%. The holotype MZUTI 3353 was found on the ground, whereas the paratype MZUTI 3355 was found 50 cm above the ground in a bush. Neither were found close to water, but were active after a rainy day. In light of this new species and the updated material we have located and examined (Tables 1, 2), we have prepared updated accounts for the tribe and the other PageBreakspecies. Hopefully, these will serve as useful descriptive summaries for taxonomic boundaries, species delimitation, and the assignment of new specimens and populations to species-level groups. We focus primarily on the external morphological characters that will be of greatest use for identifying specimens in the field and from PageBreakpreserved collections. In some cases, more detailed information can be found in the original descriptions cited. The tribe name was introduced in the PhD thesis of Jenner (1981), for which availability as a published work is ambiguous. We conservatively continue to credit the name to her, rather than treat it as unavailable and re-describe it ourselves.

Jenner, 1981 Jan, 1863 (type genus by original designation) Fritts & Smith, 1969 Peracca, 1896 Apparently from the Greek diaphoros for “differentiated” and lepis for “scales,” likely referring to the enlarged vertebral scale row as compared to the rest of the dorsal scales. A group of relatively small-sized (<550mm SVL) dipsadine snakes restricted to the Darien of Panama and northern Andes of South America with fused prefrontals and either an expanded vertebral scale row () or expanded zygapophyses and neural spines in adults ( and ).

Notes.

The tribe name has also been spelled ‘’ by Sheehy (2012), but is the correct spelling based on the suffix –lepis, for which the stem is –lepid + –ini. This is a greatly restricted definition of over the original description (Jenner 1981), which included , , , , , , , , and . Jan, 1863 Werner, 1923 Jan, 1863 (type species by monotypy) Apparently from the Greek diaphoros for “differentiated” and lepis for “scales,” likely referring to the enlarged vertebral scale row as compared to the rest of the dorsal scales. Relatively small-sized (<550mm SVL) dipsadine snakes restricted to the Darien in Panama and northern Andes of South America, with 16–25 maxillary teeth, 10–13 infralabials, 8 or 9 supralabials, fused prefrontals, internasals in contact, loreal present, 1–3 postoculars, 157–197 ventrals, 84–141 subcaudals, dorsal scales in (19–21)-19-17 rows, and expanded vertebral scale row with weak to strong double keeling. This genus was validly described by Jan (1863), and re-described by Werner (1897). Werner (1901) later incorrectly deemed Jan’s name a nomen nudum, and re-described the genus and type species, designating a neotype. However, this was an PageBreakerror of interpretation, later realized by Werner himself (Werner 1929), and neither the re-description or neotype designation have any nomenclatural validity (see Bogert 1964). The lower subcaudal counts for some specimens likely represent truncated tails. Werner, 1923 14860, locality given only as “Colombia.” Apparently from the Latin for “smooth,” referring to the anterior dorsal scales. Relatively small-sized snake (350mm SVL) with 10 infralabials, 8/9 supralabials, 2 postoculars, internasals in contact, fused prefrontals, loreal present, nuchal collar apparently present, 16/18 maxillary teeth, 157 ventrals, 84 subcaudals, 19-19-17 dorsal scale rows, vertebral scale row is enlarged, with single keels on lateral dorsal scale rows and double keels on enlarged vertebral scale row weak to absent anteriorly and weak posteriorly. Uniformly light-colored venter and dark-colored dorsum in preservative. Nothing is known of the hemipenes or vertebrae. Known only from the type specimen. The original description states that the dorsal scales are smooth, but weak keels are evident throughout the posterior portion of the body. A specimen at Harvard, reportedly from Leticia, Amazonas, Colombia, bears the identification (MCZ R-143839). Upon examination, this specimen is clearly not on the basis of divided prefrontals (versus united in ), lack of an enlarged bicarinate vertebral scale row (versus presence), and presence of an ocellated dorsal color-pattern (versus uniformly colored dorsum). The overall resemblance is of sp. Jan, 1863 ZSM 2708/0, locality given only as “Andes of Ecuador.” We revise this by subsequent restriction (sensu Smith 1953) to Milpé, Pichincha province, Ecuador (0.035, -78.87; 1076m), the locality of one of the specimens (MZUTI 3322) examined here. Relatively small-sized snakes (276–524mm SVL) with 23–25 maxillary teeth, 10–13 infralabials, 8 or 9 supralabials, 1–3 postoculars with the lower occasionally resembling a subocular and the middle occasionally resembling a temporal, fused prefrontals, internasals in contact, loreal present, incomplete nuchal collar present in juveniles (MZUTI 3322) fading ontogenetically, 181–197 ventrals, 131–141 subcaudals, (19–21)-19-17 dorsal scale rows, strong keels present on dorsal scales, and enlarged, bicarinate vertebral scale row. Uniformly cream-colored venter and dark-brown to black dorsum. Lumbar vertebrae are constricted near the middle, zygapophyses and neural spines are not expanded. The hemipenis has been briefly described (Bogert 1964), but prior to modern classifications of the organ PageBreak(Zaher 1999), and needs to be examined in more detail. Ranges at low to middle elevations (~300–1600m) along the Pacific versant from the Darien in Panama to central Ecuador. Most likely after Moritz Wagner, who collected the holotype (see Bauer 2013), and not Johann Andreas Wagner as suggested by previous authors (Beolens et al. 2011). The re-description and neotype designation ( 18915) of Werner (1901) have no nomenclatural validity (see Bogert 1964). Fritts & Smith, 1969 Fritts & Smith, 1969 (type species by monotypy) (Boulenger, 1898) From the Greek emmochlion for “a socket for a bar” and ophis for “snake,” referring to the unique interlocking vertebrae (Fritts and Smith 1969). Relatively small-sized (~250mm SVL) terrestrial snakes restricted to the Pacific Andean slopes of NW Ecuador, with a small number (<17) of maxillary teeth, 8 supralabials, 8 infralabials, fused prefrontals, internasals in contact, loreal absent, fewer than 150 ventrals, fewer than 100 subcaudals, dorsal scales in 19 rows without reduction, trunk vertebrae with lateral expansion of the zygapophyses, and expanded zygapophyses forming a rod-and-groove mechanism in , but not in . Both species are known only from the types. The hemipenis of has been briefly described (Fritts and Smith 1969), but prior to modern classifications of the organ (Zaher 1999), and needs to be examined in more detail. The organ is unknown in , as the sole known specimen is female (Sheil 1998). Fritts & Smith, 1969 UIMNH 78795, 4 km. E Río Baba bridge, 24 km. S Santo Domingo de los Colorados, Pichincha, Ecuador, ~600 m. After Dr. Charles Fugler, who collected the holotype. A terrestrial snake from the Pacific Andean slopes of NW Ecuador, diagnosable by 16 maxillary teeth, 8 infralabials, 8 supralabials, 2 postoculars, internasals in contact, loreal absent, nuchal collar absent, 140 ventrals, 97 subcaudals, dorsal scales in 19 rows without reduction, strong keels, and zygapophyses expanded laterally forming rod–and–bar assembly. Type locality is surrounded by banana plantations. Little else is known about the habits or habitat of the species. Known only from the type specimen, a male, collected by C. Fugler in February 1966. (Boulenger, 1898) Boulenger, 1898 BMNH 1946.1.12.30, Paramba, Ecuador (=Parambas, Imbabura fide Lynch and Duellman 1997) None given by Boulenger (1898); likely from the Greek for “myopia,” in reference the species’ small eyes, given as diagnostic by Boulenger. Relatively small-sized (~250mm SVL) terrestrial snake from the Pacific Andean slopes of NW Ecuador, diagnosable by 13 maxillary teeth, 8 infralabials, 8 supralabials, 1 postocular, internasals in contact, loreal absent, nuchal collar present, 145 ventrals, 93 subcaudals, dorsal scales in 19 rows without reduction, strong keels, and lateral expansion of the zygapophyses. Type locality is humid subtropical lower montane forest. Little else is known about the habits or habitat of the species. Stomach of type specimen contains remains of a gymnophthalmid lizard (Sheil 1998). Known only from the type specimen, a female, collected by W. F. H. Rosenberg in October 1897. The type specimen was re-described in great detail by Sheil (1998). Peracca, 1896 Peracca, 1896 (type species by monotypy) Hillis, 1990 (Nicéforo-Maria, 1950) Sheil & Grant, 2001 Pyron, Guayasamin, Peñafiel, Bustamante, & Arteaga, 2015 None given by Peracca (1896); presumably from the Greek syn- for “with” or “together” and ophis for “snake,” though the intended meaning of “with snake” is unclear. Relatively small-sized (~300mm SVL) dipsadine snakes of the Andes and Chocó of Colombia and Ecuador, with 16–27 maxillary teeth, 7–11 infralabials, 7–9 supralabials, fused prefrontals, loreal present, 1 or 2 postoculars, 144–184 ventrals, 88–138 subcaudals, dorsal scales in (19–21)-(17–21)-(17–20) rows, neural spine expanded and flattened, laterally expanded zygapophyses, and hemipenes slightly bilobed, semicalyculate, and semicapitate, relatively stout and bulbous, covered in large spines or hooks. On the basis of similar scale counts, but apparently without examining specimens, Amaral (1929) considered the holotype of (at the time, the only known specimen from the only known species) to be synonymous with . These snakes are extremely rare, accounting for the paucity of knowledge and unclear species-boundaries. Numerous undescribed species from many new localities are known, and await description (pers. comm., T. Grant, E. Meneses-Pelayo, O. Torres-Carvajal, and J. Arredondo). Peracca, 1896 257, locality given only as “South America.” None given by Peracca (1896); presumably from the Greek bi-color for “two colors,” referring to the dark dorsum and light venter. Small-sized (~200–400mm SVL) dipsadine snakes of the Andes and Chocó of Colombia and Ecuador, diagnosable by 16–27 maxillary teeth, 9–12 infralabials, 8 or 9 supralabials, fused prefrontals, loreal present, 2 postoculars, 152–193 ventrals, 96–143 subcaudals, dorsal scales in (19–21)-(17–19)-(17–18) weakly keeled rows, neural spine expanded and flattened, laterally expanded zygapophyses, and hemipenes slightly bilobed, semicalyculate, and semicapitate, relatively stout and bulbous, covered in large spines or hooks. Populations of this species are found in both lowland Chocóan rainforest and Andean cloud forests. Individuals are often found in leaf litter or in bushes, active at night. One collection from the Pacific Andean slopes of Ecuador (UMMZ 185886–185891) represents clutches of 2, 2, and 8 eggs, with hatchlings 125–132mm SVL. Nothing is known of diet. This is a species complex comprising at least three species-level taxa, which are distinct genetically, geographically, and morphologically (Figs 1, 3D, 4, 7, 9; Tables 1–3).
Figure 7.

Map of vouchered localities for populations: sensu stricto (purple circles), western aff. (blue circles), eastern aff. (yellow circles), and cf. (teal circles).

First are the Ecuadorean Andean highlands populations ( aff. ), which occur both on both the Pacific and Andean versants (~800–1700m). These are diagnosable by number of ventrals (152–166), subcaudals (96–122), infralabials (10 or 11), and supralabials (8 or 9), in combination. One individual (UMMZ 91550) has 24/27 maxillary teeth. The southernmost individual we examined (MZUTI 4180) has a very low number of ventral scales (152) compared to the remaining populations (160–166). Populations east and west of the Andes may also be a distinct species (O. Torres-Carvajal, pers. comm.), and are presented separately here. Most records from the Pacific versant north of the Río Toachi appear to represent (see below); one specimen reported from north of the river (BMNH 1940.2.30.31) may be mis-labeled, mis-identified, or the locality mis-referenced, or the species may be sympatric at some localities north of the river. Second are the Chocóan populations from NW Ecuador, and presumably SW Colombia (~200–300m). These match the holotype in having 174–183 ventrals, 129–138 subcaudals, 8 supralabials, and typically 9 infralabials, though one specimen from further south (MZUTI 4175) has 11. We revise the type locality of by subsequent restriction (sensu Smith 1953) to Tobar Donoso, Carchi Province, Ecuador (1.19, -78.50), locality of several specimens examined here (Tables 1, 2; Figs 1, 4, 7, 9), to cement this association. Thus, this population represents sensu stricto in the case of future revision. Third are the Colombian Andean highland populations (~1400–1500m; see Nicéforo-Maria 1970), which differ from the holotype in having 184–193 ventrals (versus 180), 127–131 subcaudals (versus 136), and 10–12 infralabials (versus 9). This group likely represents a third species, cf. . While we refrain from describing these additional -group species here based on limited current sampling, the PageBreakpopulations described above likely represent at least two (Ecuadorean Andean highland and Colombian Andean Highland) if not three (E and W Ecuadorean and Colombian Andean highland) species. Hillis, 1990 KU 197107, 4 km SE Tandayapa, Pichincha Province, Ecuador. Paratype. KU 164208, 9km SE Tandayapa, Pichincha Province, Ecuador. From the Latin for “calamity,” referring to accidents that befell the original collectors (Hillis 1990). A group of relatively small (~450mm SVL) dipsadine snakes of the cloud forests of the Pacific versant of the Andean highlands of Ecuador diagnosable by 9–11 infralabials, 7–9 supralabials, fused prefrontals, internasals separated, loreal present, 1 or 2 postoculars, 163–166 ventrals, 110–125 subcaudals, dorsal scales in (21–23)-19-17 weakly keeled rows, neural spine expanded and flattened, and laterally expanded zygapophyses. Known from middle to high-elevation (~1900–2200m) cloud forests north of the Río Toachi. Nothing is known of diet or reproduction. A detailed description was also provided by Hillis (1990). The hemipenes have likely not been examined. Easily confused with ; at least one specimen (QCAZ 11931) from near the type locality was originally mis-identified (O. Torres-Carvajal, pers. comm.). We suggest that all populations north of the Río Toachi are likely to represent . As mentioned above, one specimen apparently matching (BMNH 1940.2.30.31) is known from Río Soloya near Mindo north of Río Toachi, but this may have been mis-labeled, or mis-referenced PageBreakgeographically. The specimen of “ examined by Zaher (1999), QCAZ 452, cannot be located (O. Torres-Carvajal, pers. comm.), but originates from Chiriboga, Pichincha Province, Ecuador, north of Río Toachi, and thus may represent an . If this is the case, the hemipenes of and are nearly identical (Zaher 1999; Martinez 2011). Finally, one specimen sequenced here from Tambo Tanda (MZUTI 3694) appears to have aberrantly subdivided head scales, possessing PageBreakone extra postocular, and 2 extra supralabials and infralabials (Fig. 8), which are misshapen and abnormally small. The badly damaged paratype also appears to have two postoculars on one side (O. Torres-Carvajal, pers. comm.). Thus, we concur with Hillis (1990) that one postocular, 7 or 8 supralabials, and 9 infralabials (along with the divided internasals and smooth anterior dorsal scale-rows) are generally diagnostic of the species, but with rare individual variation. (Nicéforo-Maria, 1950) Nicéforo-Maria, 1950 /CJSP uncat., from N of Albán, cen. Cundinamarca Dept., cen. Colombia. After the Instituto de La Salle, in Bogotá (Nicéforo-Maria 1950). Smaller (~300mm SVL) dipsadine snakes of the Amazonian versant of the Andes of Ecuador and Colombia, diagnosable by 24 maxillary teeth, 10 or 11 infralabials, 7–9 supralabials, fused prefrontals, internasals in contact, loreal present, 1 or 2 postoculars, nuchal collar absent, 144–165 ventrals, 101–126 subcaudals, dorsal scales in (19–23)-(19–22)-(17–21) strongly keeled rows even on head and neck, venter dark in some populations, neural spines expanded and flattened, and laterally expanded zygapophyses. Known from low to high elevations (~500–2000m) along the Amazonian versant of the Andes from central Colombia to central Ecuador. Nothing is known of diet or reproduction. The hemipenes are very similar to both and (Bogert 1964; Zaher 1999; Martinez 2011). Much like , this species as currently described has a large geographic and elevational range, with wide variation in phenotype. There is significant variation in the number of dorsal scale rows and reduction thereof. One specimen from Ecuador (MCZ R-156873) has only one postocular and 7 supralabials, but otherwise matches the species. All other specimens have 2 and 8, respectively. Another specimen from Ecuador (MECN 2220) has 165 ventrals and 117 subcaudals with 19-19-17 scale rows, and is thus indistinguishable from aff. , with the exception of the strong keels on the nuchal scales and geographic distance from the nearest highland populations of aff. . All other specimens of have 144–156 ventrals, and most have (21–23)-(21–22)-(19–21) dorsal scale rows. Thus, it seems exceptionally likely that this is a species complex, possibly divided between highland and lowland, or northern and southern populations. Sheil & Grant, 2001 UVC 11858, from Hacienda San Pedro, about 6 km south El Queremal, Municipio Dagua, Departamento del Valle del Cauca, Colombia. UVC 11580, from type locality. From the Latin plecto- for “braided” or “woven” and veretbralis for “vertebrae,” referring to the appearance of the interlocking zygapophyses viewed from above (Sheil and Grant 2001). Relatively small (~200mm SVL) dipsadine snakes of the Pacific versant of the Andean Highlands of W Colombia, diagnosable by 24 maxillary teeth, 7 or 8 infralabials, 7 or 8 supralabials, fused prefrontals, internasals in contact, loreal present, 1 postocular, nuchal collar present, 144–147 ventrals, 79–91 subcaudals, dorsal scales in 19-19-17 weakly keeled rows, neural spines expanded and flattened, and laterPageBreakally expanded zygapophyses forming a partially interlocking complex. The type locality is a middle elevation (~1800m) cloud forest. Both known specimens were collected in moist leaf litter; one was active at night. The stomach of the holotype contained a (: ). Known only from the holotype and paratype (apparently juveniles), though other material has apparently been collected in Colombia, near the type locality (T. Grant and E. Meneses-Pelayo, pers. comm.). The hemipenes have not been examined. A more detailed description of the two specimens is provided by Sheil and Grant (2001). Given our restriction of the name, we also provide the following re-description of the re-delimited . Note that we have not performed a comparative examination of a large series of preserved material, and these data are summarized from the literature (Dunn and Dowling 1957; Savage 2002; Kohler 2008; McCranie 2011) to provide a basis for future revisions. Cope, 1871 Cope, 1871 (type genus by monotypy) Cope, 1871 Boulenger, 1895 (Holotype BMNH 1946.1.15.62, “Salidero, NW Ecuador, 350ft”) [subjective junior synonym of Taylor, 1951 (Holotype KU 28710, “’Morehead’ Finca, 5 miles southwest of Turrialba, Costa Rica”) [subjective junior synonym of USNM 12427, type locality “Isthmus of Darien [Panama]” From the Greek nothos for “bastard” and opsis for “appearance,” with Cope (1871) apparently referring to putative mimicry of . A relatively small-sized (<350mm SVL) dipsadine snake, ranging in Central and South America from Honduras to Colombia and Ecuador, in lowland and middle-elevation rainforests, 250-900m, distinguishable from nearly all other similar or related snakes in the area by the rugose, granular nature of the dorsal scales, in particular lacking differentiation of the cephalic scales with the exception of well-defined internasals and poorly defined frontal and parietals, which are separated by rows of irregular, undifferentiated scales. Color pattern consists of irregular and poorly defined blotches of blackish or light, dark, and yellowish brown. With respect to the characters described here for diaphorolepidine species, typically exhibits 19–21 maxillary teeth, 9–13 supralabials, 11–16 infralabials, 149–162 ventrals, 81–112 subcaudals, dorsal scales in (24–30)-(26–30)-(22–26) rows, SVL of 151–320mm, and tail length of 61–133mm (see Dunn and Dowling 1957). This taxon has historically been divided up into as many as three species (see Dunn and Dowling 1957), though only a single species is currently recognized. There may be cryptic variation or undiscovered diversity within this group. Note that PageBreakthe family name was originally spelled by Cope (1871), but –ops– is the correct stem from –opsis, and (and ) is thus the correct spelling, as adopted by later authors.

Discussion

Systematics of and

Corroborating previous results, we find that current supra-generic classification in does not accurately reflect the phylogeny and describe natural groups in many cases (Pyron et al. 2011; Grazziotin et al. 2012). Support for monophyly and placement of many genera is low, and many other genera are apparently non-monophyletic. Efforts to clarify this situation are underway, sampling more taxa and characters (F. Grazziotin, pers. comm.). Only ~250 out of ~900 dipsadine species (Wallach et al. 2014) are sampled here for a few genes, but cryptic and undiscovered diversity is likely much higher in the group, and will require extensive additional sampling of taxa and characters to arrive at a stable phylogenetic and taxonomic resolution. The taxonomy of has been contentious for quite some time (Cadle 1984a,b,c; Zaher 1999; Zaher et al. 2009; Grazziotin et al. 2012; Sheehy 2012), and will likely require extensive additional sampling of taxa and characters to provide a stable taxonomic resolution. In particular, we find that is not monophyletic as historically defined, but that is strongly nested within a primarily Central American clade, with and . We restrict tribe Cope, 1871 to . We resurrect and re-delimit Jenner, 1981 to include only , , and . Whereas remains unsampled in the molecular phylogeny, it appears to be the sister-taxon of based on morphological data (Hillis 1990). However, our phylogeny suggests that many of the morphological characters previously used to define supra-generic groups in (see Savitzky 1974; Wallach 1995) are subject to strong and rapid convergence. Thus, future studies may find an alternative placement for this genus. Finally, the genus is weakly nested within a primarily South American clade, and remains incertae sedis.

Species limits in

Larger sample sizes reveal expanded ranges of diagnostic characters previously used to delimit species in . These will hopefully assist future researchers in describing new taxa, and re-delimiting species boundaries. In particular, both and may comprise multiple distinct species. Additional DNA sequencing and meristic and mensural measurements of more specimens should help clarify taxonomic boundaries. In the case of , the Chocóan populations in Ecuador and presumably nearby Colombia match the description of the holotype, and thus likely represent the source of the original specimen, which remains to be re-described in detail. Contrastingly, highland populations in the Andean Highlands of Ecuador and Colombia are morphologically and genetically distinct, and both likely represent undescribed species. In the Ecuadorean Andes, populations of this taxon occur on both the Pacific and Amazonian versants, which may also be distinct from each other. The sampled specimen of is weakly nested within the sampled specimens of . A wide range of squamation and color pattern is observed in , which may represent cryptic species, as well as potential mis-identification of examined specimens. Finally, a cloud-forest population from the Pacific versant in SW Ecuador represents a new species described here as , allied to . Understanding the geographic distribution and genetic diversity in these taxa will require additional genetic sampling, which is hampered by the rarity of these species. One of the most distinctive features of diaphorolepidine species is the highly modified condition of the vertebrae, in which the prezygapophyses and postzygapophyses are broadly expanded, forming ridges, and occasionally interlocking (Bogert 1964; Fritts and Smith 1969; Hillis 1990). Given the difficulty of preparing the skeletal material and the extreme rarity of specimens, this was not examined for or any additional specimens examined here. However, this may be a crucial character for future systematic revisions in the group, possibly utilizing micro-CT scanning or radiography. Another possible source of information for delimiting species are the hemipenes. The organs are highly similar in and most species (Bogert 1964; Jenner 1981; Hillis 1990; Zaher 1999). Our observations agree with previous authors that the hemipenes are not strongly differentiated among species, though larger comparative series may reveal characters that serve to better diagnose species-level groups. In particular, the hemipenes are “nearly identical” in and (Zaher 1999; Martinez 2011), and our examination of shows no obvious qualitative differences. It is possible that speciation is primarily ecological or allopatric in this group, and thus there is little physical reproductive isolation.

Conclusions

Higher-level taxonomy in is still partially unresolved, and many genera and supra-generic groups are either non-monophyletic, or poorly supported and weakly placed. This includes Cope, 1871, which must be restricted to , if it is used at all. We resurrect and re-delimit Jenner, 1981 to include only , , and . The genus remains incertae sedis. Revised and expanded diagnoses in support the distinctiveness of all currently recognized taxa. Cryptic species are likely present in and A new population from the cloud forest of SW Ecuador is morphologically and genetically distinct, and we here name it . We hope that these PageBreakdata will provide a robust platform for future researchers to examine species boundaries in , as additional work clearly remains to be done. This is hampered, however, by the extreme rarity of these species.

GenBank accession numbers for and outgroup species analyzed here.

Species12S16SCYTBND4CMOS
Adelphicos quadrivirgatum--GQ895853-GQ895796
Alsophis antiguaeAF158455AF158524---
Alsophis antillensisFJ416691FJ416702FJ416726FJ416800-
Alsophis manselli-AF158528FJ416727FJ416801-
Alsophis rijgersmaeiFJ416697FJ416708FJ416729FJ416803-
Alsophis rufiventrisFJ416698FJ416709FJ416730FJ416804-
Alsophis sajdaki--FJ416731FJ416805-
Alsophis siboniusFJ416692FJ416703FJ416728FJ416802-
Amastridium sapperi--GQ334479GQ334580-
Apostolepis albicollarisJQ598793JQ598856--JQ598965
Apostolepis assimilisGQ457781GQ457724--GQ457843
Apostolepis cearensisJQ598794JQ598857--JQ598966
Apostolepis dimidiataGQ457782GQ457725JQ598917-GQ457844
Apostolepis flavotorquataJQ598795JQ598858GQ895854-GQ895798
Arrhyton dolichuraAF158438AF158507FJ416721FJ416795-
Arrhyton procerumAF158452AF158521FJ416723FJ416797-
Arrhyton redimitumAF158439AF158508FJ416720FJ416794-
Arrhyton supernumAF158436AF158505FJ416718FJ416792-
Arrhyton taeniatumAF158453AF158522FJ416717FJ416791-
Arrhyton tanyplectumAF158446AF158516FJ416722FJ416796-
Arrhyton vittatumAF158437AF158506FJ416719FJ416793-
Atractus aff. iridescens MZUTI4122-KT944037KT944049KT944056-
Atractus albuquerqueiGQ457783GQ457726JQ598918-GQ457845
Atractus badiusAF158425AF158485---
Atractus duboisi MZUTI62-KT944041-KT944059-
Atractus dunni MZUTI2650-KT944038KT944050KT944057-
Atractus elaps--EF078536EF078584-
Atractus flammigerusAF158402AF158471---
Atractus gigas MZUTI3286-KT944043KT944053KT944061-
Atractus iridescens MZUTI3758--KT944052--
Atractus iridescens MZUTI3759-KT944039KT944051KT944058-
Atractus major ANF1545-KT944045---
Atractus resplendens MZUTI3996KT944036KT944042KT944055KT944060-
Atractus reticulatusJQ598798JQ598886--JQ598970
Atractus schachJQ598799AF158486--JQ598971
Atractus sp. MZUTI4178-KT944040--KT944066
Atractus trihedrurusGQ457784GQ457727JQ598919-GQ457846
Atractus typhon MZUTI3284-KT944044KT944054KT944062-
Atractus wagleri--GQ334480GQ334581-
Atractus zebrinusJQ598800JQ598861--JQ598972
Atractus zidokiAF158426AF158487---
Boiruna maculataGQ457785JQ598862GQ895855-GQ895799
Borikenophis portoricensisFJ416696AF158517AF471085U49308AF471126
Borikenophis variegatusFJ416700FJ416711FJ416734FJ416808-
Caaeteboia amaraliGQ457807GQ457747JQ598921-GQ457867
Calamodontophis paucidensGQ457786GQ457728--GQ457848
Caraiba andreaeAF158442AF158511FJ416743FJ416817-
Carphophis amoenusAY577013AY577022AF471067-DQ112082
Carphophis vermis--KP765656--
Clelia cleliaAF158403AF158472--JQ598973
Coluber constrictorL01765L01770EU180432AY487040AY486937
Coniophanes fissidens--EF078538EF078586-
Conophis lineatusGQ457788JQ598865JQ598924-JQ598975
Conophis vittatus--GQ895861-GQ895805
Contia longicaudae--GU112407GU112427-
Contia tenuisAY577021AY577030GU112401AF402658AF471134
Crisantophis nevermanniGU018152GU018169---
Cryophis hallbergi--GQ895863EF078544GQ895807
Cubophis cantherigerusAF158405AF158475AF544669FJ416818AF544694
Cubophis caymanusFJ416693FJ416704FJ416745FJ416820-
Cubophis fuscicaudaFJ416695FJ416706FJ416747FJ416822-
Cubophis ruttyiFJ416699FJ416710FJ416746FJ416821-
Cubophis vudiiAF158443AF158512FJ416744FJ416819-
Diadophis punctatusAF544765AY577024EU193700EU193987AF471122
Diaphorolepis wagneri MZUTI3322-KR814752-KR814775KR814764
Diaphorolepis wagneri MZUTI3752-KR814753-KR814777KR814766
Diaphorolepis wagneri MZUTI3901-KR814754-KR814778KR814767
Dipsas albifronsJQ598803JQ598866JQ598925--
Dipsas articulataJQ598804JQ598867---
Dipsas catesbyiJQ598805Z46496JQ598926EF078585JQ598977
Dipsas indicaGQ457789GQ457730--GQ457850
Dipsas neivaiGQ457790GQ457731--GQ457851
Dipsas pratti--GQ334482GQ334583-
Dipsas variegataAF158406AF158476---
Drepanoides anomalusGQ457791GQ457732GQ895866-GQ895810
Echinanthera melanostigmaJQ598806GU018174JQ598928--
Echinanthera undulataJQ598807JQ598870JQ598929-JQ598978
Elapomorphus quinquelineatusGQ457794GQ457735JQ598930-GQ457855
Erythrolamprus aesculapiiGQ457795GQ457736GQ895871-GQ895814
Erythrolamprus almadensisJQ598808JQ598871--JQ598979
Erythrolamprus atraventerJQ598809JQ598872--JQ598980
Erythrolamprus brevicepsAF158464AF158533---
Erythrolamprus ceiiJQ598810JQ598873--JQ598981
Erythrolamprus cursorJX905310JX905314---
Erythrolamprus epinephelusGU018158GU018176---
Erythrolamprus jaegeriGQ457809GQ457749--GQ457869
Erythrolamprus juliaeAF158445AF158514---
Erythrolamprus miliarisJQ598811AF158480JQ598931-JQ598982
Erythrolamprus mimusGU018157GU018175---
Erythrolamprus poecilogyrusJQ598812JQ598875---
Erythrolamprus pygmaeusGU018154GU018172---
Erythrolamprus reginaeJQ598813JQ598876--JQ598983
Erythrolamprus typhlusGQ457811GQ457751--GQ457871
Farancia abacuraZ46467Z46491U69832DQ902307AF471141
Farancia erytrogrammaAY577017AY577026KP765663--
Geophis carinosus--GQ895872-GQ895815
Geophis dubius--KC917319--
Geophis godmaniJQ598814JQ598877JQ598932--
Geophis juarezi--KC917315--
Geophis latifrontalis--KC917322--
Geophis occabus--KC917323--
Geophis turbidus--KC917321--
Gomesophis brasiliensisGQ457796GQ457737---
Haitiophis anomalusFJ666091FJ666092---
Helicops angulatusGQ457797GQ457738AF471037-AF471160
Helicops carinicaudusJQ598815---JQ598984
Helicops gomesiGQ457798GQ457739--GQ457858
Helicops hagmanniJQ598816JQ598878--JQ598985
Helicops infrataeniatusGQ457799GQ457740JQ598933-GQ457859
Heterodon nasicusGQ457801AY577027KP765664-GQ457861
Heterodon platirhinosAY577019AY577028GU112412AF402659JQ598986
Heterodon simusAY577020AY577029AF217840DQ902310AF471142
Hydrodynastes bicinctusGQ457802GQ457742JQ598935-GQ457862
Hydrodynastes gigasGQ457803GQ457743GQ895873-GQ895816
Hydromorphus concolor--GQ895874-GQ895817
Hydrops triangularisGQ457804GQ457744AF471039-AF471158
Hypsiglena affinis--GU353241EU363055-
Hypsiglena chlorophaeaEU728577EU728577EU728577EU728577-
Hypsiglena janiEU728592EU728592EU728592EU728592-
Hypsiglena ochrorhynchaEU728578EU728578EU728578EU728578-
Hypsiglena sleviniEU728584EU728584EU728584EU728584-
Hypsiglena tanzeri--EU728588EU363044-
Hypsiglena torquataEU728591EU728591EU728591EU728591AF471159
Hypsirhynchus callilaemusAF158440AF158509FJ416737FJ416811-
Hypsirhynchus feroxAF158447AF158515GQ895875FJ416816GQ895818
Hypsirhynchus funereusAF158451AF158520FJ416739FJ416813-
Hypsirhynchus parvifronsAF158441AF158510FJ416740FJ416814-
Hypsirhynchus polylepisAF158450AF158519FJ416738FJ416812-
Hypsirhynchus scalarisAF158449AF158518FJ416741FJ416815-
Ialtris dorsalisAF158456AF158525FJ416735FJ416809-
Ialtris haetianusAF158458AF158527FJ416736FJ416810-
Imantodes cenchoaEU728586EU728586EU728586EU728586GQ457865
Imantodes chocoensis--KC176250--
Imantodes gemmistratus--GQ334487EF078557-
Imantodes inornatus--GQ334489EF078559-
Imantodes lentiferusAF158463AF158532KC176252EF078561-
Leptodeira annulataGQ457806GQ457746FJ416713FJ416787AF544690
Leptodeira bakeri--GQ334518GQ334618-
Leptodeira frenata--EF078532EF078580-
Leptodeira maculata--GQ334524GQ334623-
Leptodeira nigrofasciata--GQ334526EF078581-
Leptodeira polystictaEU728590EU728590EU728590EU728590-
Leptodeira punctata--EF078530EF078577-
Leptodeira rubricata--GQ334527GQ334631-
Leptodeira septentrionalisGU018148GU018163KC176243KC176255-
Leptodeira splendida--EF078521EF078569-
Leptodeira uribei--EF078531EF078579-
Lygophis anomalusJQ598817JQ598879---
Lygophis elegantissimusGQ457808GQ457748--GQ457868
Lygophis flavifrenatusJQ598818JQ598880---
Lygophis lineatus----DQ469789
Lygophis meridionalisGQ457810GQ457750--GQ457870
Lygophis paucidensJQ598819---JQ598987
Magliophis exiguumFJ416694AF158526AF471071FJ416798AF471117
Magliophis stahli--FJ416725FJ416799-
Manolepis putnamiJQ598820JQ598881JQ598936-JQ598988
Mussurana bicolorGQ457787GQ457729--GQ457849
Ninia atrataGQ457814JQ598882JQ598937GQ334659GQ457874
Nothopsis rugosus ASL493GU018159GU018177---
Nothopsis rugosus MZUTI3682-KR814760KR814770KR814779KR814768
Oxyrhopus clathratusGQ457815GQ457754--GQ457875
Oxyrhopus formosusJQ598821AF158482---
Oxyrhopus guibeiJQ598822JQ627291JQ598938-JQ598989
Oxyrhopus melanogenysJQ598823AF158489--JQ598990
Oxyrhopus petolariusGU018144GU018170GQ334554GQ334660-
Oxyrhopus rhombiferGQ457816GQ457755--GQ457876
Oxyrhopus trigeminusJQ598824JQ598884JQ598939--
Paraphimophis rusticusJQ598802JQ598864JQ598923-JQ598974
Phalotris bilineatusJQ598827JQ598887JQ598943--
Phalotris lativittatusJQ598825JQ598885--JQ598991
Phalotris lemniscatusGQ457817GQ457756JQ598941-GQ457877
Phalotris mertensiJQ598826----
Phalotris nasutusGQ457818GQ457757GQ895880-GQ895822
Philodryas aestivaGQ457819GQ457758--GQ457879
Philodryas agassiziiGQ457823GQ457762GQ895883-GQ457883
Philodryas argenteaGQ457842GQ457780JQ598944-GQ457899
Philodryas baroniJQ598828JQ598888---
Philodryas georgeboulengeri--GQ895898-GQ895838
Philodryas mattogrossensisGQ457820GQ457759--GQ457880
Philodryas nattereriJQ598829JQ598889AF236806-JQ598992
Philodryas olfersiiJQ598830AF158484JQ598945-JQ598993
Philodryas patagoniensisGQ457821JQ627296AF236808-GQ457881
Philodryas psammophideaGU018149GU018168---
Philodryas viridissimaAF158419AF158474AF236807--
Phimophis gueriniGQ457822GQ457761--GQ457882
Pseudalsophis dorsalisJQ598832JQ598892JQ598946-JQ598994
Pseudalsophis elegansAF158401AF158470JQ598947-JQ598995
Pseudoboa coronataGQ457824GQ457763--GQ457884
Pseudoboa neuwiediiAF158423AF158490GQ895884-GQ895825
Pseudoboa nigraAF544775GQ457764JQ598948-AF544729
Pseudoeryx plicatilisGQ457826GQ457765GQ895885-GQ895826
Pseudoleptodeira latifasciataEU728579EU728579EU728579EU728579-
Pseudotomodon trigonatusGQ457827GQ457766--GQ457887
Psomophis genimaculatusGQ457828GQ457767--GQ457888
Psomophis jobertiGQ457829GQ457768GQ895887-GQ895828
Psomophis obtususJQ598836JQ598896---
Ptychophis flavovirgatusGQ457830GQ457769--GQ457890
Rhachidelus braziliJQ598837JQ598897JQ598952--
Rhadinaea flavilata--AF471078-AF471152
Rhadinaea fulvivittis--EF078539EF078587-
Rodriguesophis iglesiasiJQ598831JQ598891GQ895881-GQ895823
Sibon nebulatusEU728583EU728583EU728583EU728583AF544736
Sibon noalamina-KP209376---
Sibynomorphus mikaniiGQ457832JQ627297JQ598954-GQ457892
Sibynomorphus neuwiediJQ598838JQ598898---
Sibynomorphus turgidusJQ598839JQ598899---
Sibynomorphus ventrimaculatusJQ598840JQ598900--JQ598997
Siphlophis cervinusJQ598841JQ598901GQ895888-JQ598998
Siphlophis compressusGQ457833GQ457772--GQ457893
Siphlophis longicaudatusJQ598842JQ598902--JQ598999
Siphlophis pulcherGQ457834GQ457773JQ598955-GQ457894
Sordellina punctataJQ598843JQ598903JQ598956-JQ599000
Stichophanes ningshaanensisKJ719252KJ719252KJ719252KJ719252KJ638718
Synophis bicolor MZUTI4180-KT944048-KT944065KT944069
Synophis bicolor MHUA14577KR814751KR814758KR814773-KR814769
Synophis bicolor MZUTI3529-KR814759KR814771KR814780KR814762
Synophis bicolor MZUTI4175-KT944046-KT944063KT944067
Synophis bicolor UTA R-55956--JX398697JX398557-
Synophis calamitus KU197107KR814622KR814640KR814697KR814711KR814663
Synophis calamitus MZUTI3694-KR814755KR814772KR814774KR814765
Synophis lasallei MZUTI4181-KT944047-KT944064KT944068
Synophis zaheri MZUTI3353-KR814756-KR814776KR814761
Synophis zaheri MZUTI3355-KR814757-KR814781KR814763
Tachymenis peruvianaGQ457835GQ457774--GQ457895
Taeniophallus affinisJQ598844JQ598905JQ598957-GQ457853
Taeniophallus brevirostrisGQ457793GQ457734JQ598958-GQ457854
Taeniophallus nicagusJQ598845JQ598906--JQ599001
Tantalophis discolor--EF078541EF078589-
Thalesius viridisAF158468AF158538---
Thamnodynastes hypoconiaJQ598846----
Thamnodynastes laneiGQ457836GQ457775---
Thamnodynastes pallidusGU018155GU018166---
Thamnodynastes rutilusGQ457837GQ457776--GQ457896
Thamnodynastes strigatusJQ598847JQ598907JQ598959--
Thermophis baileyi--EU864148KF595097EU496922
Thermophis zhaoermiiGQ166168GQ166168GQ166168GQ166168KF514882
Tomodon dorsatumGQ457838GQ457777GQ895892-GQ895833
Tretanorhinus nigroluteus--GQ895893-GQ895834
Trimetopon gracileGU018160GU018178---
Tropidodipsas sartorii--EF078540EF078588-
Tropidodryas serraJQ598848JQ598908JQ598961--
Tropidodryas striaticepsGQ457839GQ457778AF236811--
Uromacer catesbyiAF158454AF158523FJ416714FJ416788-
Uromacer frenatusAF158444AF158513FJ416715FJ416789-
Uromacer oxyrhynchusFJ416701FJ416712FJ416716FJ416790-
Xenodon dorbignyiGQ457812GQ457752--GQ457872
Xenodon guentheriJQ598849JQ598909---
Xenodon histricusGQ457813GQ457753JQ598962-GQ457873
Xenodon matogrossensisJQ598850JQ598910---
Xenodon merremiGQ457840JQ598911JQ598963-GQ457898
Xenodon nattereriJQ598851JQ598912---
Xenodon neuwiediiGQ457841GQ457779AF236814--
Xenodon pulcherJQ598852JQ598913---
Xenodon semicinctusGU018156GU018173GQ895877--
Xenodon severusJQ598853Z46474JQ598964--
Xenopholis scalaris GFM825-JQ598915---
Xenopholis scalaris JPVGU018145GU018164---
Xenopholis scalaris KU222204--GQ895897-GQ895837
Xenopholis scalaris WED57797JQ598854---JQ599002
Xenopholis undulatus R6955JQ598855JQ598916--JQ599003
  9 in total

1.  Partitionfinder: combined selection of partitioning schemes and substitution models for phylogenetic analyses.

Authors:  Robert Lanfear; Brett Calcott; Simon Y W Ho; Stephane Guindon
Journal:  Mol Biol Evol       Date:  2012-01-20       Impact factor: 16.240

2.  The phylogeny of advanced snakes (Colubroidea), with discovery of a new subfamily and comparison of support methods for likelihood trees.

Authors:  R Alexander Pyron; Frank T Burbrink; Guarino R Colli; Adrian Nieto Montes de Oca; Laurie J Vitt; Caitlin A Kuczynski; John J Wiens
Journal:  Mol Phylogenet Evol       Date:  2010-11-11       Impact factor: 4.286

3.  Dissecting the major American snake radiation: A molecular phylogeny of the Dipsadidae Bonaparte (Serpentes, Caenophidia).

Authors:  Nicolas Vidal; Maël Dewynter; David J Gower
Journal:  C R Biol       Date:  2010-01-22       Impact factor: 1.583

4.  Phylogeny of the Colubroidea (Serpentes): new evidence from mitochondrial and nuclear genes.

Authors:  R Lawson; J B Slowinski; B I Crother; F T Burbrink
Journal:  Mol Phylogenet Evol       Date:  2005-09-19       Impact factor: 4.286

5.  A phylogeny and revised classification of Squamata, including 4161 species of lizards and snakes.

Authors:  R Alexander Pyron; Frank T Burbrink; John J Wiens
Journal:  BMC Evol Biol       Date:  2013-04-29       Impact factor: 3.260

6.  Mitochondrial DNA phylogeography of the polytypic North American rat snake (Elaphe obsoleta): a critique of the subspecies concept.

Authors:  F T Burbrink; R Lawson; J B Slowinski
Journal:  Evolution       Date:  2000-12       Impact factor: 3.694

7.  MAFFT multiple sequence alignment software version 7: improvements in performance and usability.

Authors:  Kazutaka Katoh; Daron M Standley
Journal:  Mol Biol Evol       Date:  2013-01-16       Impact factor: 16.240

8.  A new Andean species of Philodryas (Dipsadidae, Xenodontinae) from Ecuador.

Authors:  Hussam Zaher; Juan C Arredondo; Jorge H Valencia; Ernesto Arbeláez; Miguel T Rodrigues; Marco Altamirano-Benavides
Journal:  Zootaxa       Date:  2014-04-04       Impact factor: 1.091

9.  MrBayes 3.2: efficient Bayesian phylogenetic inference and model choice across a large model space.

Authors:  Fredrik Ronquist; Maxim Teslenko; Paul van der Mark; Daniel L Ayres; Aaron Darling; Sebastian Höhna; Bret Larget; Liang Liu; Marc A Suchard; John P Huelsenbeck
Journal:  Syst Biol       Date:  2012-02-22       Impact factor: 15.683

  9 in total
  2 in total

1.  Large-scale molecular phylogeny, morphology, divergence-time estimation, and the fossil record of advanced caenophidian snakes (Squamata: Serpentes).

Authors:  Hussam Zaher; Robert W Murphy; Juan Camilo Arredondo; Roberta Graboski; Paulo Roberto Machado-Filho; Kristin Mahlow; Giovanna G Montingelli; Ana Bottallo Quadros; Nikolai L Orlov; Mark Wilkinson; Ya-Ping Zhang; Felipe G Grazziotin
Journal:  PLoS One       Date:  2019-05-10       Impact factor: 3.240

2.  Molecular phylogeny of Atractus (Serpentes, Dipsadidae), with emphasis on Ecuadorian species and the description of three new taxa.

Authors:  Alejandro Arteaga; Konrad Mebert; Jorge H Valencia; Diego F Cisneros-Heredia; Nicolás Peñafiel; Carolina Reyes-Puig; José L Vieira-Fernandes; Juan M Guayasamin
Journal:  Zookeys       Date:  2017-03-15       Impact factor: 1.546

  2 in total

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