Leptochromus laselva Lord, Carlton, and Leschen, 2014

Lord, Nathan P., Carlton, Christopher E. & Leschen, Richard A. B., 2014, A New Species ofLeptochromusMotschulsky (Coleoptera: Staphylinidae: Scydmaeninae) from Costa Rica, with Notes on Morphology and Natural History, The Coleopterists Bulletin 68 (1), pp. 119-125 : 119-125

Leptochromus laselva Lord, Carlton, and Leschen , new species

( Figs. 1–10 )

Diagnosis. Leptochromus laselva is distinguished from all other members of the genus by the larger body size, the well-developed, elongate postgenal process, the elongate, distinctly forked cuticular process on maxillary palpomere II, and the male genitalic characters given below.

Description of Male Holotype. Length 3.74 mm; body uniformly light orange to amber in color; vestiture consisting of long, suberect, golden setae, fairly dense over vertex, pronotum, and elytra ( Figs. 1–2 ). Head width 0.95 mm cuticular postgenal process well-developed, greatly elongate, longer than lateral width of eye at widest, narrow, parallel-sided; apex of postgenal process bearing 3 stout, spine-like setae, 2 posterior setae abutting, projecting postero-ventrally, single anterior seta projecting antero-ventrally ( Fig. 4 ). Antennae ( Figs. 5–6 ) nearly as long as body; antennomere I 6–7X as long as wide, 0.90 mm long, as long as antennomeres II–IV combined, gradually swollen apically; antennomeres II–XI elongate, subcylindrical, slightly swollen apically; antennomere II shorter than III, 2.7X as long as wide, antennomeres III-XI subequal in length, 4.0–4.6X as long as wide; antennomere XI subcylindrical, widest near middle, 4X as long as wide, narrowing to rounded point apically. Maxillary palpi ( Fig. 7 ) elongate, 1.98 mm long, nearly as long as antennomeres I–V; maxillary palpomere II sinuate at base, gradually expanding apically, bearing 1 elongate cuticular process at basal 1/3, process as long as horizontal diameter of eye; cuticular process forked apically, subsymmetrical, branches of fork well-developed, each branch bearing 1 stout bristle apically; maxillary palpomeres III+IV slightly longer than palpomere II; palpomere III elongate, gradually expanded apically, subequal to palpomere IV; palpomere IV elongate, subcylindrical, swollen apically on outer margin, widest at apical 1/3. Pronotum widest anteriorly, 0.95 mm long, 0.90 mm wide at widest; anterior angles gradually curved, lateral margins concavely sinuate. Protrochanter with 1 midventral spine. Profemur with 3 ventral spines in basal half ( Fig. 8 ). Elytra 2.19 mm long, 1.43 mm wide. Distal margin of ventrite 6 of males with broad V-shaped notch and median longitudinal groove. Aedeagus ( Figs. 9–10 ) slightly arched in lateral view; dorsal and ventral portions of median lobe lightly sclerotized, base moderately sclerotized, ventral apex rounded; parameres wide, apices not enlarged, with 1 large apical point and 1 distinct outer subapical point; basal opening quadrate, nearly twice as long as wide.

Female Paratypes. Female genitalia similar to those described and illustrated for the genus by O’ Keefe (2002). No secondary sexual characteristics are apparent.

Variation. Size (n = 6) (ranges given with means in parentheses): Females: Antennomere I, 0.88–1.00 mm (0.92 mm); maxillary palpus, 1.86–2.02 mm (1.99 mm); head width, 0.90–1.00 mm (0.98 mm); head length, 0.57–0.71 mm (0.68 mm); pronotal width, 0.95–1.00 mm (0.97 mm); pronotal length, 0.95–1.14 mm (1.03 mm); elytral width, 1.36–1.43 mm (1.41 mm); elytral length, 2.19–2.38 mm (2.25 mm); total length, 3.81– 4.00 mm (3.91 mm). Males: Antennomere I, 0.79–0.90 mm (0.85 mm); maxillary palpus, 1.66–1.90 mm (1.84 mm); head width, 0.83– 0.95 mm (0.91 mm); head length, 0.48–0.71 mm (0.61 mm); pronotal width, 0.86–1.00 mm (0.92 mm); pronotal length, 0.95–1.04 mm (0.98 mm); elytral width, 1.26–1.43 mm (1.34 mm); elytral length, 1.98–2.26 mm (2.14 mm); total length, 3.55– 3.86 mm (3.73 mm).

One female paratype possesses four femoral spines on the left profemur, three on the right profemur (standard condition is three); one female paratype has four femoral spines on the right profemur, three on the left profemur (standard condition is three); one male paratype has four spines at the apex of the left postgenal process (anteriormost directed antero-ventrally, three posterior together, directed postero-ventrally), three on right postgenal process (standard condition is three).

The degree of sinuation of the inner margin of the parameres appeared to vary slightly among specimens, but closer inspection revealed this to be an artifact of cover slip compression on slidemounted specimens. The presence of dorsal and ventral internal marginal lines of the paramere gives a bisinuate appearance when slightly deformed, while they appear straight or gently curved on unmounted specimens.

Distribution. Thus far, L. laselva is known only from La Selva Biological Station, Costa Rica (10.43053°N, 84.0064°W), at an elevation of 68 m.

Type Material. H o l o t y p e: C O S TA R I C A: Prov. Heredia, nr. Puerto Viejo, La Selva Biol. Station, 10.43053°N, 84.0064°W, 68m. Colr: N.P. Lord, C. Carlton, J-S. Park, R. Leschen, 19 June 2012, ♂ (deposited FMNH) . Fifty-two paratypes (26♂♂, 26 ♀♀) same data as holotype ; 7♂♂ (1 dissected), 8♀♀ (1 dissected) ( LSAM) ; 3♂♂ (1 dissected), 2♀♀ (1 dissected) ( NPLC) ; 2♂♂, 1♀ ( MSBA) ; 3♂♂, 3♀♀ ( INBio) ; 2♂♂, 3♀♀ ( PJ) ; 2♂♂, 2♀♀ ( FMNH) ; 2♂♂, 2♀♀ ( NHM) ; 3♂♂, 1 ♀ ( NZAC) ; 1♂, 2♀♀ ( SOK) ; 1♂, 2♀♀ ( AMNH) ; one additional paratype (♂), as follows: Costa Rica, Heredia: Est. Biol. La Selva 50–150m 10°26′N 84°01′W INBio-OET // Canopy fog / 43 / 1-40 30-Dec-1999 Minquartia guianensis ( Arthropods of LaSelva Project , ALAS) ( INBio) .

Figures

Figs. 1–4. Leptochromus laselva, habitus. 1) Dorsal view; 2) Lateral view; 3) Ventral view; 4) Frontolateral oblique view of forebody.

Figs. 5–8. Leptochromus laselva, diagnostic details. 5) Right antennomeres 1–5; 6) Right antennomeres 6– 11; 7) Right maxillary palpus; 8) Right prothoracic leg.

Figs. 9–10. Leptochromus laselva, aedeagus.9) Dorsal view; 10) Lateral view.