Colomboniscus regressus, VANDEL, 1972

Schmidt, Christian, 2007, Revision of the Neotropical Scleropactidae (Crustacea: Oniscidea), Zoological Journal of the Linnean Society 151, pp. 1-339 : 22-23

COLOMBONISCUS REGRESSUS VANDEL, 1972

Colomboniscus regressus Vandel, 1972 – Leistikow & Wägele (1999 *); Schmalfuss (2003 *).

Material examined

Type specimens: Two ♀ [ Colombia, montane forest (Robles) between La Mesa and Mosquera, altitude 2600–2700 m, leg. Sturm, 28 June 1967, MNHN-CV]; slides with cephalothorax, second antenna, maxilliped, tergites 1 and 2, pleotelson + uropod of ♀ ( CV 5818-1 to 5818-6 ) and pleopods 1 and 2 of ♂ ( CV 5819 ) [it is not indicated from which of the five samples mentioned by Vandel (1972) the dissected specimens were taken); one anterior half, two juveniles, two mancas [ Colombia, montane forest (Robles) between La Mesa and Mosquera, altitude 2600–2700 m, leg. Sturm, 28 June 1967, SMF 12453]. All these specimens are syntypes (Map Fig. 36 ).

Description ( Figs 31–35 )

Tergites hirsute. Pale yellowish white, with only some patches of reticulate pigment of pale brown colour. Cephalothorax slightly more pigmented, with distinctly visible muscle insertion spots. Eyes absent, but with a concentration of pigment in the place where the eyes usually are. Cephalothorax with upper margin of

KEY TO SPECIES OF COLOMBONISCUS

1. In frontal view, the upper margin of the frontal shield is evenly curved; in dorsal view, it is distinctly bent backwards..................................................................................... 2

1.* In frontal view, the upper margin of the frontal shield is medially straight; in dorsal view, it is straight and not bent backwards.................................................................. Colomboniscus species 2

2. Second antenna not inflated. Tergal face with traces of reticulate pigment, especially in the region of the eyes............................................................... Colomboniscus regressus Vandel, 1972

2.* Fifth peduncular article of second antenna strongly inflated; very small, unpigmented animals about 1 mm in width; coxal plate 1 without schisma.................................... Colomboniscus tristani ( Arcangeli, 1930) .

frontal shield in frontal view evenly curved, in dorsal view medially somewhat bent backwards. Noduli laterales distant from the lateral margin but near the posterior margin of the tergites, as small as scale setae, differing from them by the shorter sheath and the more protruding sensory seta.

First antenna three-jointed, distal article as long as first and second articles together, and bearing one or two subapical and two apical aesthetascs. Second antenna of the two females from Robles and of the male (on slide) with three-jointed flagellum; the distal two articles delimited by a weak but visible suture.

Maxilliped base approximately rectangular, with some scale setae on the surface and some hairs on the laterodistal corner. Endite long and rectangular, two large setae and one lobe (or one seta and two lobes?). Maxilliped palp proximal article with two large setae, the lateral seta being somewhat smaller than the mesal seta. Second article on the mesal margin with distal tuft of one large and about five slender setae on a common socket, one smaller seta beside the socket, and one seta representing the proximal ‘tuft’. Lateral margin with one broad and one slender seta. Distal article with apical tuft of one large and more than five slender setae, and two slender setae on the lateral margin.

Male genital papilla distally truncate, with subapical orifices. Male pleopod 1 endopodite weakly curved, with a row of small setae along the dorsal spermatic furrow. In the single male examined, the row has nine setae and ends before reaching the tip. Probably this is an artefact, and the more distal setae were lost, so more specimens need to be examined. Exopodite shorter than wide, without any marginal setae or respiratory field, longer mesally than laterally. Male pleopod 2 endopodite straight, exceeding the exopodite.

Pleotelson with convex distal margin. Uropod sympodites laterally rounded, exopodites as long as visible part of the sympodites, exceeding the latter by half of their length; endopodites protruding slightly more than sympodites.

Habitat

Montane forest and Páramo. The specimens were found in moss, grass, and Espeletia , and in leaf litter ( Vandel, 1972).

Remark

The first-mentioned two females are different from the single female specimen from Tibabita. Whereas the weak pigmentation and the somewhat hirsute surface are identical, the frontal shield has a very different shape: in the two females from Robles, the upper margin is strongly curved in frontal view, as illustrated by Vandel (1972), and medially bent backwards in dorsal view; in contrast, in the female from Tibabita, the upper margin of the frontal shield is medially straight in both frontal and dorsal views. Differences like this are otherwise not known to occur within one species, and so both are provisionally regarded as distinct. Unfortunately, it is not known from which sample the male preparations were taken.

Figures

Figure 31. Geographical distribution of Neosanfilippia venezuelana (1) and N. zoiai (2): circles, material examined; squares, literature data.

Figure 32. Neosanfilippia zoiai Manicastri, 1991: ♀, 4.5 × 1.9 mm, cephalothorax 1.21 mm wide, habitus lateral; ♂, 4.1 × 1.9 mm, cephalothorax 1.21 mm wide, ventral view, cephalothorax and pleon dorsal, both paratypes (Ecuador, Esmeraldas District, Borbon, Valdez, at sea level, leg. S. Zoia, 28 July 1984, MZUF 2740).

Figure 33. Colomboniscus regressus Vandel, 1972: ♀ syntype, 3.2 mm, cephalothorax width 0.85 mm [Colombia, montane forest (Robles) between la Mesa and Mosquera, altitude 2600–2700 m, leg. H. Sturm, 28 June 1967, MNHN].

Figure 34. Colomboniscus regressus Vandel, 1972: ♀, second antenna, first antenna, maxilliped (Colombia, exact locality unknown, leg. H. Sturm MNHN CV 5818).

Figure 35. Colomboniscus regressus Vandel, 1972: ♀, coxal plates 1 and 2, ♂, pleopods 1 and 2, pleotelson and uropods (Colombia, exact locality unknown, leg. H. Sturm MNHN CV 5818–5819).

Figure 36. Geographical distribution of Colomboniscus: 1, C. regressus; 2, C. tristani.