Pselaphomorphus Motschulsky, 1855 : 15

Vásquez-Vélez, Laura M., 2016, Revision of the genus Pselaphomorphus Motschulsky, 1855 (Staphylinidae, Pselaphinae: Jubini), Zootaxa 4107 (1), pp. 1-48 : 4-8

Pselaphomorphus Motschulsky, 1855: 15

Type species. Pselaphomorphus sculpturatus Motschulsky, 1855: 15 .

Diagnosis. The genus Pselaphomorphus is characterized among members of the Jubini by the presence of the antennal tubercle cordate at its base ( Fig. 1 A) and a longitudinal sulcus on the vertex of the head ( Figs. 1 B–1E).

Description. Body length 1.5–3.3 mm. Body flattened, light brownish to reddish or dark brown in color, with yellowish pilosity, integument glabrous.

Head. Triangular to elongate, anteriorly truncate with antennal tubercle cordate at base; always with complete medial sulcus between eyes. Shape of sulcus may vary from fusiform to rectangular. Eye position anterior to medial. Clypeus rectangular, labrum bearing 14 to 16 apical setae ( Fig. 2 A). Mandibles with inner edge serrate ( Fig. 2 B). Labial palp with two palpomeres ( Fig. 2 C). Maxillary palp with four palpomeres, second elongate, third triangular and similar in length to second, fourth acuminate, as long as previous two ( Fig 2 D). Antennae 11-jointed, long and slender, with inconspicuous clava of five antennomeres in most species (‘antennal clava’ refers to antennomeres 7 to 11 progressively widening).

Pronotum. Shape pentagonal, with two longitudinal sulci and two lateral lobes, one on each side; basally with transverse sulcus separating basal lobe. Junction of pronotum and mesonotum narrow. Central portion of the pronotal disc quadrate to rectangular or oval. Presence and size of basolateral teeth variable. In some species basal lobe divided by median stria and bearing punctures ( Fig. 3 C).

Elytra and metathoracic wings. Elytra rectangular, longer in males than females. Humerus with basal suture and complete stria. Humeri dentate in females and tuberculate in males of some species. Subhumeral fovea and stria present, deeply marked in most species. Two basal elytral discal foveae ( Fig. 3 C): sutural fovea and associated sutural stria present on each elytron; basal discal fovea located more laterally and with or without discal depression. Metathoracic wings only present in males, with indistinct venation, anterior and posterior margins lined by long alar setae.

Pro-, meso- and metasternal foveal system (sensu Chandler 2001) ( Figs. 3 A and 3B). Prosternum with lateral procoxal foveae located at anterior margins of procoxal cavities. Mesoventrite with fused median mesosternal foveae (mmsf), lateral mesosternal foveae (lmsf) near anterior margin of mesoventrite and obscured by posterolateral margins of procoxae in some species; anterolateral mesosternal foveae (almsf) located between ventral margins of elytra and anterior margin of mesoventrite.

Abdomen. Five visible segments dorsally, first abdominal segment longer and wider than remaining segments in both sexes. Ventrally with six segments in males and five in females. Last ventral segment in males (VI) with a variously round or elongate depression, or depression absent.

Legs. Long and slender, with femur thicker than other segments, tarsi 3-segmented (two segments apparent). Two equal tarsal claws.

Male genitalia. Asymmetric and consisting of base (phallobase) and median lobe. Phallobase varies from symmetric (with two arms that can be long or short, or without arms) to asymmetric with arms of different size, and/or with several sclerites articulated to membranous area. Median lobe of aedeagus may be linear, either divided or entire (basally, medially or apically); in some species median lobe composed of two different lobes articulated to interior of aedeagal base. Length of median lobe from 0.1 mm to 1.0 mm. Some species with 1–2 accessory lobes that vary in shape, position and size.

Biological and collection information. Specimens of Pselaphomorphus have been collected by sifting and berleseing leaf litter, flight intercept traps, and at ultraviolet light. Habitat records list forest litter, especially in secondary forest, gallery forest and dry oak forest.

Distribution. The genus is distributed from central Mexico to northern Argentina in an altitudinal range from 0 to 3400 m a.s.l.

Figures

FIGURE 1. Head of Pselaphomorphus species in lateral (A) and dorsal (B – E) view. A. P. sculpturatus. B. P. macrommatus n. sp., C. P. iguazuensis n. sp., D. P. longissimus n. sp. E. P. carenobothrus n. sp.

FIGURE 2. Mouthparts and legs of Pselaphomorphus sculpturatus: A. Labrum. B. Dorsal view of the mandible. C. Labium: expanded mentum, prementum, labial palpi. D. Maxilla. F. Front leg. G. Middle leg. H. Hind leg.

FIGURE 3. Details of Pselaphomorphus sculpturatus, male: ventral (A ̶ B) and dorsal (C) views. A. Prothorax. B. Ventral foveae of meso- and metathorax: lpcf = lateral procoxal fovea, mmsf = median mesosternal foveae, lmsf = lateral mesosternal foveae, almsf = alnterolateral mesosternal foveae, lmcf = lateral mesocoxal foveae. C. Pronotum and elytral foveae and sulci.