Thoasia rugifrons Liebke, 1939

Erwin, Terry L. & Aldebron, Charlotte, 2018, Neotropical Thoasia Liebke, 1939 and Straneotia Mateu, 1961 of the Cryptobatida group, subtribe Agrina: Taxonomic revisions with notes on their ways of life (Insecta, Coleoptera, Carabidae, Lebiini), ZooKeys 742, pp. 57-90 : 63-65

Thoasia rugifrons Liebke, 1939 Rough-headed pentagonal arboreal carabid Figs 1A , 3A , 7

Thoasia rugifrons Liebke, 1939:129

Holotype.

(sex unknown): Type area. Venezuela. Not seen by us; however, Mroczkowski (1960) indicates that the holotype is in the Polish Academy of Sciences in Warsaw. We have determined that Liebke’s translated description is good enough for us to recognize the species without seeing the type. Our redescription is based on newly acquired specimens (see below).

Derivation of specific epithet.

The epithet, Thoasia rugifrons , is a Latinized singular feminine adjective meaning "rugose forehead."

Proposed English Vernacular Name.

Rough-headed pentagonal arboreal carabid.

Diagnosis.

With the attributes of the genus and rugifrons species group as described above and adults with elytra metallic dark blue.

Description.

(Figs 1A , 3A ). Habitus: (Fig. 1A ). Size: See Appendix 1. Length (SBL) long for genus, ABL = 4.30-4.55 mm, SBL = 4.11-4.16 mm.

Color: See diagnosis above. Luster: Elytra shiny metallic; forebody and head shiny. Microsculpture: Mostly isodiametric, well-impressed. Head: Rugae moderately coarse, mostly transverse on occiput, longitudinal adjacent to eye, slightly angulate on frons. Eye very large, sub-hemispheric, and evenly rounded anteriorly, subtly more prolonged posteriorly. Antenna moderately long, reaching humerus. Labrum very large, somewhat cordate, shallowly convex at middle. Neck constricted, width coequal to anterior margin of pronotum. Prothorax: Pronotum moderately narrow, disk centrally convex, with dense transverse rugae and two dark stripes extending longitudinally, occasionally converging at the base. Lateral margins at apical third explanate and sharply acute, becoming constricted at basal third. Hind angles moderately acute and subtly narrower than lateral margin at widest point. Pterothorax: Normal for Agrina , fully winged, wings smoky translucent. Elytron intervals 3, 5, and 7 with numerous discal setae, intervals slightly convex, side margin markedly explanate. Elytron narrow and short, moderately wider than the pronotum at the broadest part, apex truncate, slightly sinuate with distal corner obtusely rounded, disc not significantly convex, basal third not depressed. All interneurs well-impressed. Legs: Normal for Agrina , no unique modifications. Abdomen: Sparsely setiferous; normal ambulatory setae on sterna 3-5; female with three pairs of ambulatory setae on sternum 6; males with two pairs of longer setae on sternum 6. Male genitalia: Phallus (Fig. 3A .) broad with phallobase ⅓ of its length, ostium 1/3 of its length, catopic, apex short, markedly broad and shallowly rounded; endophallus moderately complex without flagellum. Parameres asymmetric, right very small, left larger, broad, apically rounded. Female genitalia: (cf. Fig. 2B ). Unstudied, but likely similar to T. manu , new species.

Dispersal potential.

These beetles are macropterous and capable of flight. They are likely moderately swift and agile runners. The two specimens were collected in flight intercept traps (FITs), one located at ground level and the other at 20 m up in the canopy.

Way of life.

The specimens were collected in January and February, where the climate is tropical, hot and humid throughout the year, with a relatively dry and slightly warmer season from July to November, and a rainy season from December to June.

Other specimens examined.

French Guiana: Cayenne , Commune de Roura, RN 2, PK22, Montagne des Chevaux, 4.7127°N, 52.3966°W, 90 m, 12 February 2012 (S. Brûlé, PH. Dalens, E. Poirier)(NMNH: ADP152522, male), 9 January 2016 (S. Brûlé, PH. Dalens, E. Poirier)(NMNH: ADP148165, female) .

Geographic distribution.

(Fig. 7 ). This species is currently known from the type locality in Venezuela and in the lowlands of French Guiana.

Note.

In Liebke’s description, his specimen measures 5.5 mm. This would mean that the range of ABL for T. rugifrons is greater than one millimeter, a significant enough variation both within this and among other species of this genus to warrant the consideration of error in measurement on his part.

Figures

Figure 1. Digital Photo-illustrations. Habitus, dorsal aspect: A Thoasia rugifrons Liebke, female, ADP 148165 B Thoasia pterosmaragdos Aldebron & Erwin, sp. n., female, ADP 148174 C Thoasia manu Erwin & Aldebron, sp. n., female, ADP 100320. Scale bar: 1.00 mm.

Figure 2. Digital Photo-illustrations. A Habitus, dorsal aspect: Thoasia surinamensis Erwin & Aldebron, sp. n., female, ADP 112239. Scale line = 1.00 mm B Female reproductive system dorsal aspect: Thoasia manu, Erwin & Aldebron, sp. n., ADP 100301. Legend, bc, bursa copulatrix; sg, spermathecal gland; sgd, spermathecal gland duct; sp., spermatheca; lt, laterotergite; co, common oviduct; gc 1, gonocoxite 1; gc 2, gonocoxite 2, des, dorsal ensiform seta, b, base of gonocoxite 2; bl, blade of gonocoxite 2. Scale bar: 0.50 mm.

Figure 3. Digital Photo-illustrations, male aedeagus in repose, dorsal, ventral, left lateral aspects: A Thoasia rugifrons Liebke, ADP 152522 B Thoasia pterosmaragdos Aldebron & Erwin, sp. n., ADP 13748 C Thoasia manu Erwin & Aldebron, sp. n., ADP 100336. Legend, lp, left paramere; rp, right paramere; pb, phallobase; bo, phallobase orifice; ps, phalloshaft; a, phalloapex; ml, median lobe. Scale bar: 0.50 mm.

Figure 7. Distribution map for known localities of Thoasia and Straneotia species.