Dolichoctis dilatata, Hunting, Wesley & Yang, Man-Miao, 2019

Hunting, Wesley & Yang, Man-Miao, 2019, A taxonomic review of the pericaline ground-beetles in Taiwan, with descriptions of new species (Coleoptera, Carabidae, Lebiini), ZooKeys 816, pp. 1-164 : 89-91

Dolichoctis dilatata sp. n. Figs 64, 65 A–D, 66, 71B, 72

Etymology.

From Latin dilatata , in reference to the distinctively wide and explanate pronotum.

Types and other material examined.

Holotype (male) labeled “Holotype” [circular, ringed with red]; "TAIWAN: Taichung Co./Dakeng Scenic Area/ base of hiking trail 4/ 24.1737N, 120.7882E"; "veg. nr. lights on trail/night. Acc. Ti-85/May 25, 2011, 475m/Coll. W. M. Hunting"; " NCHU# 101168". Two paratypes of D. dilatata : one male and one female. For further details see EH Strickland Virtual Entomology Museum Database.

Type locality.

Taiwan. Dakeng Scenic Area, Nantou county.

Diagnosis.

Specimens of this species are easily distinguished from other species of Dolichoctis by a combination of the lack of elytral maculae and the striking contrast of testaceous pronotum with rest of dorsal surface.

Description.

OBL 4.92 - 5.08 mm. Length (n = two males, one female): head 0.48 - 0.50, pronotum 0.82 - 0.92, elytra 3.00, metepisternum 0.64 - 0.72 mm; width: head 1.04 - 1.08, pronotum 1.60 - 1.68, elytra 2.33, metepisternum 0.40 - 0.44 mm.

Body proportions. HW/HL 2.08 - 2.25; PWM/PL 1.78 - 1.95; EL/EW 1.29; ML/MW 1.45 - 1.70.

Color. Fig. 64. Dorsum of head rufo-brunneous, clypeus and labrum brunneo-testaceous, lighter that head, antennae and palpi testaceous to brunneous; disc of pronotum testaceous, strikingly lighter in coloration than head and elytra, margins translucent; elytral disc rufo-brunneous, hint of iridescence in basal 1/4, margins, suture, and apical area diffuse, rufous; ventral surface testaceous; legs with trochanter and femora testaceous to brunneo-testaceous, tibia with dorsal surface partially piceous.

Microsculpture. Dorsum of head with microsculpture granulate, isodiametric, sculpticells smallest on disc, between eyes, becoming gradually larger towards base, easily visible at 50 × magnification; pronotum with transverse to somewhat transverse mesh pattern.

Macrosculpture and pilosity. Ventral surface of head distinctively rugulose; elytra with intervals somewhat convex, with several randomly scattered setigerous punctures, hardly visible at 50 ×; striae faintly punctate.

Fixed setae. Elytra with interval 3 with two punctures bearing fine setae, first near mid-length and second ~2/3 to apex.

Luster. Head capsule and pronotum moderately dull; elytra moderately glossy; ventral thoracic sterna and abdominal sterna moderately glossy.

Head. Mandibles almost entirely covered by pronotum; labrum more or less rectangular.

Pronotum. Anterior transverse impression shallow; posterior transverse impression shallow; median longitudinal impression moderately shallow; lateral margins widely explanate, apical margin deeply emarginate, forming distinctive apico-lateral lobes, posterio-lateral margins broadly rounded, obtuse.

Elytra. Hind angles slightly sinuate.

Male genitalia. Figs 65 A–D, 66. Length 0.88 - 0.96 mm. Ostium left pleuropic. Phallus cylindrical, narrowing from mid-length to apex, apex somewhat elongate and slightly spatulate, rounded at apex and with slight constriction before apex, in ventral view; endophallus, short, slightly curved just above mid-length, with two large spine fields present, one row of vertical spines basally on side closest to phallus base, one larger, vertical spine field on apical side from below mid-length to endophallus apex.

Female genitalia. Fig. 71B. Width 0.76 mm. One spermatheca (sp1), elongate and domed at the apex; spermathecal ring sclerite (srs) dividing spermatheca from spermathecal duct; one spermathecal accessory gland (sg) with spermathecal gland duct (sgd) attachment site on relatively large lobe (srsl) coming off of right side of ring sclerite when viewed from ventral aspect.

Habitat, habits, and seasonal occurrence.

The known elevational range of D. dilatata is from 475 to 740 meters. This species in only known from three specimens. One specimen was collected during the day while sweeping vegetation along a walking trail. The other two were collected at night from live tree trunks. Adults of this species are found in mixed forest of montane areas. Specimens have been collected in May, July, and October in Taiwan. Methods of collecting include sweep netting and hand collecting.

Geographical distribution.

Dolichoctis dilatata is known only from Taiwan. See Figure 72.