Sphaeroniscus pilosus, VANDEL, 1972

Schmidt, Christian, 2007, Revision of the Neotropical Scleropactidae (Crustacea: Oniscidea), Zoological Journal of the Linnean Society 151, pp. 1-339 : 62

SPHAERONISCUS PILOSUS VANDEL, 1972

Sphaeroniscus pilosus Vandel, 1972 – Leistikow & Wägele (1999 *); Schmalfuss (2003 *).

Material examined

Type specimens: One ♂, one ♀, syntypes ( Colombia, Bogotá, Montserrate montane forest, c. 3 km east of eastern border of the city, approximately in the prolongation of Calle 45; altitude c. 3150 m, in raw humus under moss; leg. H. Sturm, 7 February 1969, CV) .

Other samples: One ♂, three ♀ m ( Colombia, Valle de la Quebrada, Chico , near Bogotá, montane forest, altitude c. 3500 m, under sandstones, leg. W. Joost, 8 November 1987) .

Description ( Figs 182–184 )

Adult males 4.8 × 2.0 mm (syntype) to 8.7 × 3.5 mm, adult females 8.7 × 3.6 mm to 8.4 × 3.7 mm. Coloration brown, with pale muscle insertion spots and also slightly paler towards the coxal plates and posterior margins of the tergites; coxal plates 2–4 pale, coxal plates 5–7 and pleon-epimera centrally pale but marginally darker. All pereion tergites with a dorsofrontal paler area. Pleon medially somewhat lighter, so that it has two darker longitudinal stripes. Pereiopods weakly pigmented. Uropods dark. Second antenna also pigmented, only flagellum pale (all specimens seem to be somewhat faded). Endoantennal conglobation ability. Hairy or spiny appearance due to the long and strong tricorn setae. Noduli laterales, if present, cannot be distinguished from tricorns when viewing the whole animal. Frontal lamina tightly appressed to vertex. Eyes composed of 12 ommatidia. First coxal plate with a schisma near the posterior corner. Fifth coxal plate with slightly concave lateral margin.

First antenna three-jointed. Second antenna with three-jointed flagellum and apical cone that is longer than the distal article. Maxilliped consisting of large and quadrangular basipodite, endite, palp, epipodite. Endite distally rounded-truncate, hairy, with a simple seta on the caudal face and a small penicil on the frontal face, near the mesodistal corner. Basis covered with scales and scale setae. Maxilliped palp proximal article with one large seta in mesal position. Second article on mesal margin with proximal ‘tuft’ consisting of one seta and distal tuft of more than ten setae on a socket, two setae beside socket, and on lateral margin with one broad and one slender seta. Distal article with apical tuft of> 15 setae, and a single seta on the lateral margin.

Pereiopod 1 carpus with antennal brush of rather long scales. Male pereiopod 7 basipodite on frontal side with several longitudinal rows of scales of waterconducting system, merus with distofrontal tubercle. Dactyli with inner claw half as long as outer claw. Ungual seta with small seta beside it, which is somewhat less than half as long as the ungual seta. Dactylar seta in distal quarter fringed with setules. One smaller seta on frontal and caudal face of dactylus, and some further scales and setae.

Male pleopod 1 endopodite distally slightly curved laterally, on lateral margin with two small tubercles; row of 25 small setae along the dorsal spermatic furrow; distalmost five setae cleft into several fine hairs in their distal half. Pleopod 1 exopodite with distinct mesodistal lobe, a narrow respiratory field at the lateral margin, and small hairs on the mesal margin; no marginal setae. Male pleopod 2 endopodite slender, slightly exceeding exopodite; exopodite with strip of hairy pectinate scales along mesal margin, and some (six) marginal setae on lateral margin.

Autapomorphies

Enlarged tricorn setae producing a pilose appearance (convergency with Scleropactes pilosus ).

Remark

The syntype male is adult, despite its small size compared with the other male, as in the genital papilla, a bundle of collagen stalks can be seen.

Sphaeroniscus pilosus clearly belongs to the genus Sphaeroniscus , as defined above. Coxal plate 5 is enlarged and has a slightly concave lateral margin; both features are more weakly developed than in the other two species, but clearly visible. Moreover, a tubercle on the merus of male pereiopod 7 constitutes the second synapomorphy.

Remarkable is the superficial similarity with Scleropactes pilosus . Both are comparatively small and have a strongly pilose tergal surface. Probably this can be correlated with their habitat, but the data on the latter are too scarce.

Biology

All six specimens were collected in montane forest between 3100 and 3500 m altitude. Three females collected in November 1987 have a marsupium, which is empty in two females and contains eight embryos in the third.

Figures

Figure 182. Sphaeroniscus pilosus Vandel, 1972: syntype ♂, 4.8 × 2.0 mm, habitus, pleon dorsal, cephalothorax dorsal (Colombia, Bogotá, Montserrate montane forest, altitude c. 3150 m, leg. H. Sturm, 7 February 1969, MNHN).

Figure 183. Sphaeroniscus pilosus Vandel, 1972: syntype ♂, 4.8 × 2.0 mm, pereiopods 1 and 7 (Colombia, Bogotá, Montserrate montane forest, altitude c. 3150 m, leg. H. Sturm, 7 February 1969, MNHN).

Figure 184. Sphaeroniscus pilosus Vandel, 1972: syntype ♂, 4.8 × 2.0 mm, maxilliped, pleopods 1 and 2 (Colombia, Bogotá, Montserrate montane forest, altitude c. 3150 m, leg. H. Sturm, 7 February 1969, MNHN).