Beetles that live with ants (Coleoptera, Carabidae, Pseudomorphini): A remarkable new genus and species from Guyane (French Guiana), Guyanemorpha spectabilis gen. n., sp. n.

Among the extensive collections currently being made in Guyane (French Guiana), adults of a large and colorful species of pseudomorphine were encountered. The adults present, for the first time in the Western Hemisphere, elytra with a marked color pattern, and in addition a size considerably beyond that of the rest of the members of all other known genera in the Western Hemisphere. Both of these attributes, however, are well known in the Australian pseudomorphine fauna. This new species is described and illustrated and a revised key to the Western Hemisphere genera is included. The type locality of Guyanemorpha spectabilis gen. n., sp. n. is Guyane,Risquetout, PK20, 4.916°N, 52.516°W, 12m altitude.

Introduction

Surprising taxa of Carabidae continue to surface as collections from remote places and new habitats are explored (e.g., Erwin 2000, 2004; Erwin and Geraci 2008). Another such taxon has been discovered in various parts of Guyane during ongoing biotic inventories in reserved areas of Guyane and exploration of that country’s insect biodiversity by The Entomological Society Antilles-Guyane (SEAG) (cf. Erwin et al. 2012). The species is remarkable because the adults (Fig. 1) present, for the first time in the Western Hemisphere, elytra with a marked color pattern, and in addition a size considerably beyond that of the rest of members of the other known genera in the Western Hemisphere. Both of these attributes, however, are well known in the Australian pseudomorphine fauna (Baehr 1992, 1997) and it is likely a greater variety of color forms will be found in the future in South America.

Figure 1.

sp. n., female holotype, ADP132101; Risquetout, PK20, Guyane. Habitus and female genital tract glued to card, dorsal aspect, ABL = 13.2mm.

Specimens and methods

Included in this study are a total of 4 specimens from other institutions and private collections (Appendix 1). “Methods and species concepts follow those previously described (Ball 1959; Erwin and Kavanaugh 1981; Kavanaugh and Erwin 1991). The species validation and diagnosis format follows as closely as possible that suggested in Erwin and Johnson (2000). Measurements of length (ABL, SBL) and width (TW) follow those of Ball (1972) and Kavanaugh (1979): ABL; SBL, PL, and LE; and TW.”

(apparent body length), measured from apex of labrum to apex of the abdomen

(standardized body length), equals the sum of the lengths of the head (measured from apex of clypeus to a point on midline at level of the posterior edge of compound eyes)

(pronotal length ), measured from apical to basal margin along midline

(elytron length), measured from apex of scutellum to apex of the longer elytron

(total width), measured across both elytra at their widest point with suture closed

“Habitus and attribute images of the adult beetles portray most of the character states referred to in the key provided. Male and female genitalic presentations are standard for descriptive taxonomy of carabid beetles, and in this case are digital photo-illustrations (Erwin 2011). The images of the adult and its parts were made with a Visionary DigitalTM high resolution imaging system. Figure captions include an ADP number, which is a unique identification number for the specimen that was illustrated PageBreakor imaged and links the specimen and associated illustrations and/or image to additional information in electronic databases at the NMNH.”

“Geographical data are presented based on all known specimens of each species available at the time of manuscript preparation. Georeferences have been determined from locality information provided on specimen labels. Latitude and longitude are reported in decimal degrees. A distribution map is provided for the species [Fig. 5]. Here, an English vernacular name is proposed, as vernacular names are becoming increasingly needed in conservation and/or agricultural and forestry applications, as well as for the Encyclopedia of Life (www.eol.org),” (Erwin and Amundson in press).

Figure 5.

Distribution dot map for known localities of sp. n.

Accounts of taxa

Western Hemisphere genera of Pseudomorphini Newman 1842

Erwin, gen. n. Guyane (French Guiana)

Erwin & Geraci, 2008. Brazil, Ecuador, Guyane, Perú

(Baehr, 1997). Middle and South America

(s. str.) Kirby, 1825. USA south to Argentina (incl. Caribbean islands)

Erwin & Geraci, 2008. Perú

Erwin & Geraci, 2008. México, Honduras

Erwin & Geraci, 2008. Ecuador

Key to the Western Hemisphere genera of Pseudomorphini Newman 1842

Newman, 1842

http://species-id.net/wiki/Pseudomorphini

Pseudomorphini Newman, 1842: 365 (as Pseudomorphites)

Proposed english vernacular name.

False-form beetles.

Taxonomy.

Stable at the generic level.

Classification.

According to Ober and Maddison (2008), Pseudomorphini appears as a branch of the higher Carabidae and associated with Graphipterini and Orthogonini; according to Erwin and Geraci (2008), the adelphotaxon is the tribe Orthogonini. All three tribes are associated in some way with ants or termites. Male genitalia of pseudomorphines have a bonnet-shaped phallobase as in the lebiomorphs, yet their accompanying parameres are large and nearly symmetrical (and in some species the parameres are sparsely setiferous), as in some primitive lineages of the family. Many known lineages of Pseudomorphini have been so highly selected for life with ants (and possibly termites) that external structures do not help much in discovering more normal carabid relatives (cf. Erwin and Amundson, in press).

Taxonomy references.

Baehr (1992, 1997); Erwin and Amundson (in press); Erwin and Geraci (2008); Notman (1925), Ogueta (1967).

Larval references.

Erwin (1981); Lenko (1972); Liebherr and Kavanaugh (1985), Moore (1964, 1974, 1983).

Erwin gen. n.

http://zoobank.org/66A2E5B7-0831-4E1E-8AD2-ECE683F0AD8D

http://species-id.net/wiki/Guyanemorpha

Type species.

Erwin, sp. n.

Proposed english vernacular generic name.

Guyane False-form beetles

Adelphotaxon.

Probably (Baehr, 1997) (see Erwin and Geraci 2008 for phylogeny).

Description.

Head (Fig. 2) without supraorbital setigerous punctures, nor any accessory setae; frontal impressions absent. Labrum barely visible with anterior margin shallowly emarginate, quadrisetose; clypeus markedly wide, nearly obscured in dorsal aspect by protruding frons, with obtuse setiferous lateral corners. Eyes slightly convex; small gena with numerous stout setae. Antenna short, just reaching anterior coxa in repose; antennomeres 3-9 slightly wider than 1-3, and appearing slightly flattened. Mandible markedly flattened with a very short and acute apex; outer margin ventral of the scrobe without short PageBreakstout setae. Maxillary palpi markedly short, 3-segmented, palpomeres slightly depressed, palpomere 3 truncate apically. Labial palpus with short bisetose palpomere 2; palpomere 3 markedly securiform and robust, its distal margin mostly membranous with sensory organs.

Figure 2–3.

2 sp. n., female holotype, ADP132101; Risquetout, PK20, Guyane. Head, dorsal planar aspect 3 sp. n., female paratype, ADP132105; Nouragues, Saut Pararé, Guyane. Left flight wing, dorsal aspect.

Prothorax. Pronotum (Fig. 1) much wider than head, transverse, with narrowly beaded margins; without a pair of setigerous punctures each side, apical, lateral and posterior margins with fringe of short stout setae; hind angles obtuse, broadly rounded. Prosternal process unisetiferous subapically, intercoxal process feebly beaded.

Pterothorax. Metepisternum elongate and markedly narrowed posteriorly, the outer margin about 2 times greater in length than the anterior margin, posterior margin about 0.2 times anterior margin.

Elytra. Elytron (Fig. 1) tapered, markedly narrower apically, width of elytra about equal to that of pronotum at widest point, apical margin truncate with evenly rounded humerus, interneurs and intervals effaced; parascutellar stria absent, scutellum hidden, parascutellar puncture present, marked; without fixed discal setae, surface glabrous. Lateral marginal (umbilical) series of 10 setae, arrayed throughout and widely spaced; lateral margin with fringe of short stout setae.

Hind wings. Macropterous. Venation (Fig. 3).

Legs. Short and depressed, femur posteriorly channeled for reception of tibia in repose; antennal comb notch very shallow; tibial spurs normal; anterior tarsi of male with tarsomeres 2–4 dilated slightly, ventrally each with two laterally placed rows of adhesive articulo-setae.

Abdomen. Abdominal sterna III–VII with patches of short setae and each of IV–VII with a single row of erect ambulatory setae numbering 2 to 8 setae; V and VI in male each with dense row of yellowish robust setae separated medially.

Male genitalia (Fig. 4). Phallobase hooded with small orifice, dorsum not crested; phalloshaft arched throughout its length, diameter sub-rounded to somewhat depressed dorso-ventrally; phalloapex produced, sharp, rounded, markedly depressed dorso-ventrally; endophallus orifice elongate, endophallus with dense patches of microtrichia. Parameres (C) moderately short compared to those of genus , nearly equal in length, left slightly longer and much broader than right, each apically glabrous. Ring sclerite (E) normal for family.

Figure 4.

sp. n., male paratype, ADP132103; Risquetout, PK20, Guyane. Male genitalia, median lobe and parameres labeled as in repose in male A ventral aspect B right lateral aspect C left lateral aspect D dorsal aspect.

Female ovipositor and genital tract (Fig. 1). Gonocoxite 2 falcate, base about as long as blade, latter relatively short, pointed distally; margins without ensiform setae; with short preapical nematiform seta.

Erwin sp. n.

http://zoobank.org/B86F564C-10FD-43CD-B257-DDE8425CF0D7

http://species-id.net/wiki/Guyanemorpha_spectabilis

Figures 1 –5

Holotype.

Guyane (French Guiana): Risquetout, PK20, 4.916°N, 52.516°W, 12m, 13 December 2010 (SEAG) (NMNH, held in trust, see below: ADP132101, female). Paratypes are listed below under other specimens examined.

Derivation of specific epithet.

The epithet “spectabilis” is a Latin adjective describing the very large and colorful beetle species.

Spectacular Guyane False-form beetle.

Diagnosis.

With the attributes of the genus as described above and color black and rufous with elytral spots (Fig. 1), color tone of head and pronotum uniform black; form broad and stout with tapered elytra; head with preapical lobe prominent but hidden in dorsal aspect beneath the frons, about 2/3 the length of the anterior margin of eye; pronotum (Fig. 1) coequal at base to elytra across humeri; elytron markedly tapered from humerus to narrower truncated apex and without interneurs or intervals, surface glabrous except parascutellar seta and 8 ombilicate setae near lateral margin.

(Figs 1, 2, 3, 4; Appendix 3). Size: Very large for a Western Hemisphere species, ABL = 13.18 to 13.51 mm, SBL = 11.05 to 12.18 mm, TW = 6.36 to 6.86 mm. PageBreakPreocular lobe-eye ratio (L/L): 0.49 to 0.54. Pronotum ratio (L/W): 1.99 to 2.16. Pronotum ratio (W/L): 2.20 to 2.29. As described for genus above and the diagnosis.

Dispersal potential.

These beetles are macropterous and have been recorded from flight intercept traps (FITs), hence fully capable of flight; they are likely swift and agile runners as other species in the Tribe. Accordingly, this species may be expected to be more broadly distributed across a wider geographical range than current records indicate.

Way of life.

Adults of other pseudomorphines in the Western Hemisphere are found in ant nests and the surrounding vicinity and possibly in termite nests (Ogueta 1967); female adults of species of PageBreak are ovoviviparous (Liebherr and Kavanaugh 1985); and larvae are ant nest inquilines (Erwin 1981, Lenko 1972). Members of occur at lowland rainforest sites and most likely live with ants. They have been found in July and December.

Other specimens examined.

Guyane: Réserve Trésor, 4.610°N, 52.279°W, 225m, 11 July 2009 (S. Brule) (BMNH, ADP124772, male paratype); Risquetout, PK20, 4.916°N, 52.516°W, 12m, 13 December 2010 (J.L. Giuglaris) (MNHP: ADP132103); Nouragues, Saut Pararé, 4.02°N, 52.41°W, 51m, 14 July 2010 (SEAG) (MNHP, ADP132105, female paratype).

Geographic distribution.

(Fig. 5). This species is currently known only from Guyane.

Note.

The holotype is currently held in trust at the National Museum of Natural History, Smithsonian Institution, Washington, DC until the planned Natural History Museum of Guyane is established, and at that time the specimen will be transferred there. See details of SEAG carabid collections in Erwin et al. 2012.

Concluding statement

Adults of share attributes with those of both (Baehr) and Erwin & Geraci. This surprising large and colorful pseudomorphine came as a shock to the author, as all other species of the Tribe in the Western Hemisphere are quite dull fulvous, rufous, or black with no, or little, color contrast on the dorsal surface. Since little in the way of life information is available for the four specimens reported herein except seasonality of adult activity and lowland habitation, only speculation based on fogging samples in Perú and Ecuador can add much to this conclusion. “The pseudomorphines are a very interesting evolutionary off-shoot of the normal carabid morphotype in both form and function and are only just now beginning to be understood in North America. The fact that species of related genera in South America are living with arboreal ants will make learning about them far more difficult. Insecticidal fogging gets adults of these species, but only tearing apart arboreal ant nests while suspended in a tree will produce their larvae, and that is not for carabidologists faint of heart.” Erwin and Amundson (in press).

1	Mouthparts not visible in dorsal aspect. Preocular lobe absent	2
1’	Mouthparts visible in dorsal aspect. Preocular lobe present	3
2(1)	Dorsal surface glabrous, markedly shiny	Notopseudomorpha (Baehr, 1997)
2’	Dorsal surface finely setiferous, not shiny	Samiriamorpha Erwin & Geraci, 2008
3(1’)	Elytron with only scutellar and ombilicate setae; with elytra markedly tapered to apex	4
3’	Elytron multisetiferous; body form rather broad and subdepressed with elytra not or barely tapered to broadly round apex	5
4(3’)	Body form narrow, somewhat cylindrical	Yasunimorpha Erwin & Geraci, 2008
4’	Body form very broad, not cylindrical	Guyanemorpha gen. n.
5(3)	Dorsal surface with dense vestiture, of very long thick erect setae equal in length at least to basal 4 antennomeres, but no pubescence; body form subconvex, elytra tapered posteriorly	Manumorpha Erwin & Geraci, 2008
5’	Dorsal surface with sparse or no long vestiture, longer setae equal in length only to at most basal 3 antennomeres, also usually with short pubescence; body form subconvex, elytra slightly tapered posteriorly or not	6
6(5’)	Major setae of dorsal surface erect or slightly curved posteriorly	Pseudomorpha Kirby, 1825
6’	Major setae of elytra posteriorly directed and markedly decumbent	Tuxtlamorpha Erwin & Geraci, 2008

Table 1.

Measurements and ratios for sp. n., all measurements are in millimeters.

Total length (sbl)
Males			Females
N	Range	Mean	N	Range	Mean
2	12.079–12.135	12.107	2	11.053–12.185	11.844
Maximum width (tw)
Males			Females
N	Range	Mean	N	Range	Mean
2	6.356–6.378	6.367	2	6.41–6.864	6.637
W of head/w of left elytron
Males			Females
N	Range	Mean	N	Range	Mean
2	1.041–1.069	1.055	2	0.980–0.991	0.986
Pronotum: width (at widest part)/length
Males			Females
N	Range	Mean	N	Range	Mean
2	2.193–2.220	2.207	2	2.253–2.327	2.29
Length of pronotum / length of head
Males			Females
N	Range	Mean	N	Range	Mean
2	1.959–2.027	1.993	2	2.040–2.285	2.163
Apparent body length (abl)
Males			Females
N	Range	Mean	N	Range	Mean
2	13.510–14.480	13.995	2	13.180–14.180	13.68
Pre-ocular length / eye length
Males			Females
N	Range	Mean	N	Range	Mean
2	0.435–0.554	0.494	2	0.520–0.551	0.535