Selasia sp.

Parekar, Harshad, Rosa, Simone Policena, Packova, Gabriela, Patwardhan, Amol & Kundrata, Robin, 2025, The first immature snail-eating soft-bodied click beetle (Elateridae: Agrypninae: Drilini) from the Oriental realm: A putative larva of Selasia Laporte from India, Zootaxa 5666 (1), pp. 115-124 : 116-119

? Selasia sp. (active larva)

( Figs 1–5 ; Supplementary Video 1: https://doi.org/10.5281/zenodo.13923861)

Material examined. One larval specimen: INDIA: Maharashtra, Mumbai, Versova , 22.xi.2022, leg. Meet Kaskar (ZKJSSC) .

Diagnosis. The here-examined larva can be easily distinguished from all known larvae of Drilini by the mostly yellowish brown to light brown body with major portions of meso- and metathoracic tergites, abdominal tergites I–VI and an anterior portion of tergite VII dark brown to black ( Figs 1 , 5 ), and by the urogomphi apically with three thick spines ( Figs 1A , 2E ). See Discussion for the comparison of this larva with other known active Drilini larvae.

Description. Mature active larva. Body about 13 mm long, dorsoventrally flattened. Head and prothorax light brown, except darker tips of mandibles and contour of stemmata; tergites of mesothorax, metathorax dark brown to black, except posterior angles which are light brown; abdominal tergites I–VI dark brown to black, except lateral processes which are light brown; tergite VII and lateral processes yellowish brown, except anterior margin which is dark brown; tergite VIII and lateral processes yellowish brown; ventral surface, legs and lateral pleural processes yellowish brown, except bases of lateral processes and sternal patches on segments I–VII which are dark brown; urogomphi brown. Vestiture consisting of long ferruginous setae, stiff and increasing in density from mesothorax to urogomphi.

Head ( Figs 2A, B ; 4A ) prognathous, heavily sclerotized, 1.7 times wider than long, sides rounded, posterior margin almost straight medially, weakly emarginated lateroventrally; lateral margin near antennifer with short to long setae; dorsal surface with short to long setae lateroventrally and medially near clypeolabrum, anterior ventrolateral lobes (adnasalia) obliquely truncate with 2–3 setae, clypeolabrum depressed, about 0.3 times as wide as head, anterior margin almost straight, anterior angles rounded, edges paler, translucent anteriorly, fused to frons, frontoclypeal suture vaguely indicated; one stemma on each side, epicranial sutures absent; ventral surface glabrous, gular sutures absent. Antennifer membranous, antenna ( Figs 2A , 4B ) entirely retractable, with stiff long setae; antennomere I with sides divergent apicad, setae near apex, 1.7 times longer than antennomere II; antennomere II subparallel-sided, setae distributed throughout; ventrolateral sensorium with base sclerotized, parallel-sided, apex membranous conical. Mandible ( Fig. 3E ) falcate, about 3 times longer than wide, unidentate, incisor edge smooth, outer margin with short to long setae on basal half, channel opening dorsally near apex. Maxilla ( Figs 2B , 3A–D ) with stipes about twice longer than wide, parallel-sided, anterior margin obliquely truncate, inner angle produced, posterior margin rounded, row of short to long setae along lateral margin, a few setae on ventral surface; cardines absent, corresponding area membranous; maxillary palp 4-segmented, slightly flattened, palpomeres I and III very short, ring-shaped, palpomere II about 5 times longer than IV, covered with short setae, apical palpomere wedge-shaped; galea 1-segmented, suboval, as large as maxillary palp. Labium ( Figs 2B , 3A–D ) with prementum trapezoidal, about 1.5 times wider than long, three lateral pairs of long setae on anterior half, one pair of shorter, finer setae parasagittally on anterior margin; postmentum parallel-sided, divergent posterad, 6.0 times as long as wide, with several short setae, denser anteriorly, one pair of longer setae posteriorly; labial palp as long as prementum, apical palpomere 0.3 times as long as basal; ligula weakly produced.

Thorax ( Figs 1 , 2A–D ) with tergites well sclerotized; prothorax ( Fig. 2A ), 2.2 times wider than long; mesothorax and metathorax subequal, each one 4.0 times wider than long, 0.7 times as long as prothorax, sides divergent posterad, posterior angles produced in dorsal view; leg ( Fig. 2C, D ) short, densely covered with stiff long setae and short spiniform darker setae; pretarsus with one or two long setae at base.

Abdomen ( Fig. 1 ) with sides widened up to segment V, then gradually narrowed to segment IX; with tergites evenly sclerotized and pigmented, except tergite VII, each with anterior margin darker; with lateral tergal and pleural processes on segments I–VIII; pleural processes about twice longer than tergal processes; spiracles biforous, between tergal and pleural processes; sternites less sclerotized than tergites, with sublateral elongate darker stains. Urogomphi ( Fig. 2E ) about 3 times longer than wide, apex with three distinct spines (one apically, one submedially, and one laterally before apex; visible in dorsal view).

Biology and ecology. The here-examined larva was active in the second half of November. Although it was collected in the washroom, it probably came there through the window from an undisturbed plot of forested patch which was just behind the washroom window. To observe and record the predatory behaviour of the larva in the laboratory, it was offered a live snail ( Tanychlamys sp. ) collected from that nearby forest. The larva gradually reached the snail and then captured it. After some time, the larva actively preyed on the snail (Supplementary Video 1: https://doi.org/10.5281/zenodo.13923861). Attempts to keep the larva alive were unsuccessful.

Figures

FIGURE 1. Habitus of active larva of?Selasia sp. from India. A, dorsal view; B, ventral view; C, lateral view. Scale bars = 3.0 mm (A–C).

FIGURE 2. Morphology of active larva of?Selasia sp. from India. A, head and pronotum, dorsal view; B, head and prosternum, ventral view; C, thorax, lateral view; D, thorax, ventral view; E, urogomphi, dorsal view. Scale bars = 1.0 mm (A–E).

FIGURE 3. Mouthparts of active larva of?Selasia sp. from India. A, maxillolabial complex, dorsal view; B, close-up of anterior half of maxillolabial complex, dorsal view; C, maxillolabial complex, ventral view; D, close-up of anterior half of maxillolabial complex, ventral view; E, right mandible. Scale bars = 0.5 mm (A–E).

FIGURE 4. Morphology of active larva of?Selasia sp. from India. A, drawing of head, dorsal view; B, drawing of antenna. Scale bars = 1.0 mm (A), 0.25 mm (B).

FIGURE 5. Active larva of?Selasia sp. from India with its snail prey, Tanychlamys sp. A–B, larva approaching the snail; C, larva preying on the snail. Not to scale.