Amphicrossus adustipennis Dasgupta and Pal, 2019

Dasgupta, Jhikmik & Pal, Tarun Kumar, 2019, Three New Species of Amphicrossus Erichson, 1843 (Coleoptera: Nitidulidae: Amphicrossinae) from Northeast India, with a Review of the Genus in the Region, The Coleopterists Bulletin 73 (2), pp. 307-320 : 318-319

5. Amphicrossus adustipennis Dasgupta and Pal , new species

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Type Material. Holotype male, genitalia dissected and mounted on cover slip and pinned with the holotype. Original label: “ INDIA: Arunachal Pradesh, Namdapha Tiger Reserve, Zero Camp, 27.4455° N, 96.5358° E, 1 ex., 08.iv.1981, S. Biswas leg.”

Description. Oval, globose, ventrally subdepressed, dark brown, finely punctate dorsum ( Fig. 27 ); cuticle with moderately dense and long, golden, decumbent pubescence; elytra bearing a pair of dense, long, erect setal clusters near and slightly above the midpoint of elytral suture. Head: Transverse, about as broad as long, frons subdepressed; punctures on frons and vertex round and moderately deep, about size of an eye facet, separated from each other by 1–2 puncture diameters; eyes moderately large and moderately projected, about 0.3X as long as head, outer margin rounded, somewhat finely facetted; temple indistinct; golden yellow setae present on frons and vertex. Antenna about 1.3X as long as head; antennal club about 1.4X as long as broad, club segments compact, about 0.3X as long as antenna. Pronotum: Transverse (LP:WP = l.0:1.8), anterior margin broadly emarginate; lateral margins arcuate, posterior margin bisinuate, anterior angles sharply obtuse, posterior angles obtusely rounded, lateral margins bordered with a dense row of moderately long cilia about 1/3 as long as eye. Rather convex ( Fig. 31 ), surface distinctly punctate, punctures about as large as those on vertex of head, separated by 1–2 puncture diameters; moderately dense, decumbent setae on disc. Scutellum: Transverse, about 1.3X as broad as long, triangular with sides somewhat arcuate; punctures round, about size of an eye facet, separated by 1–2 puncture diameters; setae very fine, short, sparse. Elytra: About 1.2X as broad as long, humeral angles nearly right-angled, sides rather arcuate, borders somewhat explanate, apices separately rounded ( Figs. 34, 37 ); punctures round, about size of those on pronotum, separated by 1–2 puncture diameters; moderately dense, long, decumbent pubescence interspersed with somewhat short, fine, appressed setae. Abdominal tergites: Partially covered by elytra; pygidium with truncate apex ( Fig. 40 ). Venter: Uniformly reddish brown. Prosternal process subparallel with bulbous apex. Abdominal ventrite ( Fig. 43 ) with hypopygidium extended as a short process with truncate apex arising from the midpoint of the preceding abdominal ventrite. Anal sclerite as in Fig. 46 . Aedeagus: Broadly elongate, membranous median lobe with subparallel sides and a single median strut; tegmen with paired leg-like parameres, tuft of very long setae arising 1/3 distance from apices of parameres, tegminal struts arising from basal extremity of each paramere ( Figs. 52 , 57–58 ). In lateral view ( Fig. 49 ), parameres distinctly curved, gradually narrowing from base to apex; apex distinctly pointed, a tuft of setae arising from ventral margin of the parameres.

Measurements. TL = 4.83 mm; WH = 0.80; LA = 1.08 mm; LP = 1.54 mm; WP = 2.87 mm; LE = 2.46 mm; WE = 3.10 mm.

Etymology. The species name is derived from the Latin word ‘adustus’ meaning ‘brown (burnt)’ and ‘pennis’ meaning ‘wing’ referring to the brownish elytra of the species.

Distribution. INDIA: Arunachal Pradesh.

Comparative Notes. The species resembles Amphicrossus solodovnikovae Kirejtshuk, 2005 in the shape and position of the tuft of setae on the dorsal surface of the elytra, the last abdominal ventrite and hypopygidium, and the shape of the male genitalia, but it can be differentiated from the latter by the shape of the spiculum gastrale, the parameres widely spaced and somewhat parallel-sided in ventral view, bearing a short brush of setae on the ventral side of the apices, and the median lobe distinctly longer ( Fig. 52 ) (vs. parameres closely situated and distinctly broadened in the apical half in dorsal view and median lobe shorter in A. solodovnikovae ).

Figures

Figs. 21–28. Amphicrossus species in Northeast India. 21–22) A. discolor, dorsal and ventral views, respectively; 23–24) A. kabitae, dorsal and ventral views, respectively; 25–26) A. brunneus, dorsal and ventral views, respectively; 27) A. adustipennis, dorsal view; 28) A. densatus, dorsal view (photograph by Andrew Cline).

Figs. 29–46. Amphicrossus species. Pronota: 29) A. discolor; 30) A. brunneus; 31) A. adustipennis. Right elytron, dorsal view: 32) A. discolor; 33) A. brunneus; 34) A. adustipennis. Elytron, lateral view: 35) A. discolor; 36) A. brunneus; 37) A. adustipennis. Pygidium: 38) A. discolor; 39) A. brunneus; 40) A. adustipennis. Last abdominal ventrite: 41) A. discolor; 42) A. brunneus; 43) A. adustipennis. Anal sclerite: 44) A. discolor; 45) A. brunneus; 46) A. adustipennis.

Figs. 47–52. Amphicrossus species, male genitalia. 47) A. discolor, lateral view; 48) A. brunneus, lateral view; 49) A. adustipennis, lateral view; 50) A. discolor, ventral view; 51) A. brunneus, ventral view; 52) A. adustipennis, ventral view.

Figs. 53–60. Amphicrossus species, male genitalia, lateral and ventral views, respectively. 53–54) A. kabitae;