Anillinus depressus (Jeannel)

Sokolov, Igor M., Reddell, James R. & Kavanaugh, David H., 2014, Life beneath the surface of the central Texan Balcones Escarpment: genus Anillinus Casey, 1918 (Coleoptera, Carabidae, Bembidiini): new species, a key to the Texas species, and notes about their way of life and evolution, ZooKeys 417, pp. 71-101 : 82-84

Taxon classification Animalia Coleoptera Carabidae

Anillinus depressus (Jeannel) Figs 1C, 8

Micranillodes depressus Jeannel 1963a: 58. Holotype, a female, in NMNH, glued on cardboard and labeled as in Fig. 1C.

Anillinus depressus (Jeannel), Bousquet 2012

Recognition.

Adults of Anillinus depressus are distinguished easily from those of other Texan species of the genus by the following combination of external characters: small size, markedly elongated habitus, laterally oblique pronotal basal margin and simple (i.e., neither truncated nor incised elytral apex).

Redescription.

Small-sized for genus (SBL 1.45 mm).

Habitus. Body form (Fig. 1C) subdepressed, subparallel, elongate (WE/SBL 0.34), head large for genus compared to pronotum (WH/WPm 0.83), pronotum wide in comparison to elytra (WPm/WE 0.85).

Color. Body rufotestaceous, appendages testaceous.

Microsculpture. Present over all dorsal surfaces of head, pronotum and elytra, but much finer on head and pronotum than on elytra.

Head. Labium with mental tooth present; mentum and submentum separated by suture.

Prothorax. Pronotum relatively long (LP/LE 0.41) and slightly transverse (WPm/LP 1.29), with lateral margins almost rectilinear and strongly constricted posteriorly (WPm/WPp 1.33). Anterior angles indistinct, posterior angles slightly obtuse (100-110°). Width between posterior angles less than between anterior angles (WPa/WPp 1.10). Basal margin oblique laterally, so posterior angles noticeably shifted forward.

Elytra. Widely depressed along suture, of normal length (LE/SBL 0.57) and narrow for genus (WE/LE 0.61), with traces of 4-5 striae. Humeri distinct, rounded, in outline forming right angle with longitudinal axis of body. Lateral margins subparallel, slightly divergent at basal fourth, evenly rounded to apex in apical third, without subapical sinuation. Umbilicate series with 9 pores, 8th and 9th of which not geminate. Apex of elytron rounded with distinct sutural angle.

Genitalia not examined.

Geographical distribution.

The single known specimen of this species was collected in Travis County, Texas (Fig. 8, black diamond), in the vicinity of the Balcones Fault Zone.

Way of life.

No precise data provided in original description or on labels associated with the holotype.

Relationships.

Contrary to Jeannel’s description ( 1963a), the type specimen possesses a distinct mental-submental suture on the labium and normal, not shortened, elytra [although the apical half of the right elytron is missing]. Chaetotaxy of the elytra cannot be investigated because of their poor condition, but Jeannel cited and illustrated three discal setae for the specimen. If so, then this specimen can be treated as a representative of Anillinus , as was done by Bousquet (2012). Configuration of the last pores of the umbilicate series may be of low importance for a separate generic status of the specimen, because it is known that this character is variable within “good” genera of anillines ( Giachino and Vailati 2011). The small size and reduction of microsculpture on the foreparts of the body of its members make this species morphologically distinct from other Texan anillines. Perhaps, this combination of characters reflects adaptations for living in a rather different environment in comparison with the other species.