Pericalus (s. str.) gibbosus, Shi, Hongliang & Liang, Hongbin, 2018

Shi, Hongliang & Liang, Hongbin, 2018, Revision of genus Pericalus from China, with descriptions of four new species (Carabidae, Lebiini, Pericalina), ZooKeys 758, pp. 19-54 : 25-26

Pericalus (s. str.) gibbosus sp. n. Figs 1, 2, 19, 30, 33, 41, 52, 60

Type material.

Holotype (IZAS): male, body length = 7.2 mm, card-mounted, genitalia dissected and placed in micro vial pinned under specimen, "Myanmar, Kachin state, Putao distr., way btw. Upper Shankhaung to Wasandum; rain forest; 1075 m"; " N27.4765, E97.2060, 2016.XII.11, SHI H.L. lgt. in dead log, CAS-SEABRI exp. 2016"; "HOLOTYPE ♂ Pericalus gibbosus sp. n., des. SHI & LIANG 2018" [red label] (Fig. 19). Paratypes (2 ex.): 1 female (IZAS): same data as holotype. 1 female (IZAS), "Xizang, Mêdog; alt 800-1200 m, Chinese Academy of Science"; “1983.11.5– 10, Han Yinheng lgt."; "IOZ (E) 1891857".

Diagnosis.

Smallest species in the subgenus, body length 7.2-8.5 mm; elytra black with four round yellowish spots, posterior patch in the third and fourth intervals, sometimes expanded onto part of the second and fifth. Pronotum cordiform, lateral margins strongly sinuate before posterior angles; disc with strong wrinkles. Elytra distinctly convex; outer apical angles rounded; sutural angles blunt; third interval with three setigerous pores; striae with large but shallow punctures. Median lobe of aedeagus with apical lamella very long, approximately one-fourth length of median lobe; endophallus with six thumb tack-like spines (Fig. 33).

Comparison.

This species can be readily distinguished from other species in this subgenus. The elytral pattern is similar to that of P. dux and P. longicollis , all with four round yellowish spots, but differs from both species by the elytral posterior patch in intervals 3-4, sometimes also part of 2 and 5 (versus in intervals 4-6 or 4-7); elytra much more convex; pronotum strongly sinuate before posterior angles (versus weakly or moderately sinuate); and much smaller body size.

This species is sympatric with P. elegans sp. n., P. acutidens sp. n., and P. amplus . It can be easily distinguished from these species by the different elytra pattern, smaller size, and very convex body.

Description.

Body length 7.2-8.5 mm (male holotype 7.2 mm, female paratypes 8.2-8.5 mm). Coloration. Dorsal surface shiny blackish, with very faint violet hue on elytra; legs, antennae, mouthparts reddish brown; elytral anterior and posterior patches as single round spots, yellow or reddish yellow; the anterior one in intervals 4-7 or 4-6, the posterior one in intervals 2-5 or 3-4 (the male holotype with elytral spots smaller than those of the two females, Figs 1-2); ventral side black. Microsculpture faint and isodiametric on vertex and pronotal disc, distinct and linear on elytral intervals. Head with very strong and regular long wrinkles all through clypeus, frons and vertex, reaching or nearly reaching level of posterior margin of eyes, 6-8 wrinkles on each side; eyes strongly prominent; temporae abruptly constricted after eyes. Pronotum cordiform, PW/PL = 1.33-1.38, subequal to the width of head with eyes (PW/HW = 1.00-1.05); posterior margin a little narrower than anterior margin; lateral margins rounded in the middle, strongly sinuate and then straight before posterior angles; posterior angles sharp, nearly rectangular, projecting laterally, with a seta a little before posterior angles; lateral expansions wide; disc strongly convex and wrinkled, with a pair of faint pits on each side; sub-anterior impression distinct, median line strongly incised, not reaching posterior margin; basal fovea very deep, forming trifurcate incisions, extending medially forming W-shaped sub-posterior impression. Elytra ovate, strongly convex; EW/EL = 0.74-0.75; much wider than pronotum, EW/PW = 1.69-1.83; apical truncation weakly curved; outer apical angles rounded, sutural angles blunt, not pointed; striae deeply incised, with large but very shallow punctures; third interval with three setigerous pores, the first one at approximately basal tenth, the second near middle, the third one close to apex; the first one adjacent to the third stria, the other two close to the second stria; all intervals distinctly convex, seventh and eighth intervals tumid apically, eighth and ninth intervals with sparse fine setae aside of umbilical series; lateral expansions slightly widened at approximately basal third. Male genitalia (Fig. 33) with median lobe of aedeagus slender and bent, right margin slightly sinuate near middle; apical orifice very large, opened to the left; apical lamella very long, approximately one fourth length of median lobe, flat, in ventral view length approximately 2.8 times basal width, apex rounded; endophallus with six thumb tack-like spines, arranged in two groups, three near the base of apical orifice, the other three near base of median lobe. Right paramere short, apex truncate, not extended. Female genitalia. Internal reproductive system (Fig. 52): bursa copulatrix with a very long lobe (inferred to accommodate the large apical lamella of aedeagus); spermatheca digitiform, with weak whorl near middle, without basal pedicel, inserted on the joint of common oviduct and bursa copulatrix; spermathecal gland long, inserted near base of spermatheca, apex strongly dilated, base forming long pedicel. Gonocoxite 2 of ovipositor (Fig. 41) scimitar-shaped, abruptly bent to the outer side at apical fifth; length approximately six times basal width; outer margin with three dorsolateral ensiform setae, the basal one finer and distant from the rest two; inner margin with one doromedial ensiform seta near apex.

Distribution.

Only known from Putao (North Myanmar) and Mêdog (Southeast Xizang, China). (Fig. 60)

Etymology.

The name gibbosus is Latin, meaning humped, referring to the strongly convex elytra of the new species, which are rather flat in all the other species of this subgenus.

Habitat.

In north Myanmar (Putao), P. gibbosus sp. n. was collected under bark of a large fallen log next to a path in subtropical rainforest, elevation of 1075m. This species seems to be very rare, due to only two specimens were collected, cohabitates with P. acutidens and P. amplus . Pericalus acutidens was collected in exactly the same microhabitat together with the new species, but it has a wider elevational range and is much more common. Pericalus amplus is also rare in this area.

Remarks.

The form of the male genitalia makes P. gibbosus the most unique member in the subgenus, and in the genus as well. Unlike all other examined species, P. gibbosus has the apical lamella very long, approximately one-fourth length of median lobe (less than one tenth in the other species); and the endophallus with thumb tack-like spines (only finely scaled in other species). This species may represent an isolated lineage in the genus; however, from the external characters, P. gibbosus perfectly agrees with the subgenus Pericalus . Moreover, we suspect that Pericalus (s. str.) could be paraphyletic, because all diagnostic characters for the subgenus seem to be plesiomorphic. Nevertheless, phylogeny is not the task of the present paper, and this new species is placed in Pericalus (s. str.).