Lathrobium (Abletobium) lapidum Haberski & Caterino, 2024

Haberski, Adam & Caterino, Michael S., 2024, A review of Nearctic Lathrobium (Coleoptera, Staphylinidae), with revision and descriptions of new flightless species from the mountains of the southeastern U. S., ZooKeys 1198, pp. 193-277 : 193

Lathrobium (Abletobium) lapidum Haberski & Caterino sp. nov.

Type material.

Holotype ♂ (FMNH): "USA: VA: Dickenson Co., 37.2724°N, 82.2956°W, Breaks Interstate Park, Camp Branch Trail, VI.09.2022, C. Harden, under large rock in sandy soil nr rock face, mesic stream hollow." / "Caterino DNA voucher, Ext. MSC-11164"/ "CLEMSON ENT [QR CODE] CUAC000169038". Paratypes (1, VMNH): "USA: VA: Scott Co., 36.8584°N, 82.4477°W, Jefferson NF, N of Dungannon, VI.09.2022, C. Harden, On rock face under root/soil mat on base of boulder." / "Caterino DNA voucher, Ext. MSC-11165" / "CLEMSON ENT [QR CODE] CUAC000169039".

Diagnosis.

This species’ range might overlap with L. absconditum , L. shermani , and L. hardeni . Compared to these, it has a more rounded head, square elytral margins, and glabrous bases of the gonocoxites. It can be further distinguished from L. absconditum by its smaller size and transverse black setae on male sternite VIII. Males of L. shermani are approximately the same size but have a single setal comb on sternite VIII. Lathrobium hardeni is most similar and distinguishing the two requires comparison of genitalia. Males of L. hardeni have more-or-less symmetrical spines on the internal sac of the aedeagus, and females have a subgenital plate.

Description.

Habitus (Fig. 17A ). Large species, total body length ~ 8 mm long, FL 3.5 mm long. Coloration: body and appendages pale reddish.

Similar to L. hardeni , except posterior angles of head more strongly rounded. Eyes smaller, reduced to small white membranes occupying 1/9 lateral width of head.

Pronotum with punctures spaced one diameter apart, no line visible down midline. Posterior margin of elytra quadrate; punctures small and shallow, relatively sparse, irregularly spaced 2 × their diameters apart.

♂: Posterior margin of sternite VIII with a broad, shallow, V-shaped emargination and three transverse combs of irregularly spaced thick black setae either side of midline (Fig. 17D ). Aedeagus 1.3 mm long; ventral process long, reaching dorsal plate in lateral view, apex curved, asymmetrical (Fig. 17E, F ); dorsal plate short and oval, distal end with a curved spine; internal sac with four spines, one bulbous and covered with short spikes.

♀: Sternite VIII oblong, apex notched with micropubescence (Fig. 17C ); paraprocts undivided anteriorly, apices longer than basal portion; proctiger conical; sternum IX with valvifers and coxites fused, setose in apical 2/3 with a dense patch of thick setae at base (Fig. 17B ); subgenital plate absent.

Etymology.

The specific name is from Latin, meaning stone, because both specimens were found on or under rocks.

Distribution and ecology.

Lathrobium lapidum is known from two specimens collected in Jefferson National Forest, Virginia (Fig. 18 ). One was collected under an embedded rock, and the other beneath a root and soil mat on top of a boulder. Collected in June.

Figures

Figure 17. Lathrobium lapidum A habitus B female terminalia C female sternite VIII D male sternite VIII E aedeagus in ventral view F aedeagus in lateral view. Scale bars: 1 mm.

Figure 18. Distribution of Lathrobium lapidum (star), L. shermani (triangle), L. solum (square), L. thompsonorum (circle)