Scleropactoides curvatus, Schmidt, 2007

Schmidt, Christian, 2007, Revision of the Neotropical Scleropactidae (Crustacea: Oniscidea), Zoological Journal of the Linnean Society 151, pp. 1-339 : 38-39

SCLEROPACTOIDES CURVATUS SP. NOV.

Material examined

One ♂ holotype, two ♂, one ♀ m, one juvenile paratypes ( Venezuela, Bolivar, km 118, leg. F. Yoris, 25 September 1967, MNRJ 9677 ); one ♀ ( Venezuela, Bolivar, km 125, leg. F. Yoris, 26 September 1967, MNRJ 9678 ) .

Description ( Figs 92–97 )

Holotype male, 10.5 × 5.0 mm, cephalothorax 2.57 mm wide, 22/22 ommatidia; paratype female with marsupium, 11.5 × 6.5 mm, cephalothorax 3.08 mm wide, 24/26 ommatida; paratype male, cephalothorax 2.22 mm wide, 20/20 ommatidia.

With conglobating ability, as can be concluded from habitus, especially the latterally narrow coxal plates 4. The cephalothorax morphology allows the hypothesis that the second antennae are not included in the ball when the animal is rolled up. Cephalothorax behind the frontal shield with a deep, slightly curved transverse groove, extending to the midlength of the eyes. In the median portion, posterior margin of groove with a row of pectinate scales. Distinct lateral lobes about half as long as eyes and separated from median part of frontal shield by obtuse angles. In frontal view, linea supraantennalis medially downcurved and laterally upcurved before leading down towards the sockets of the second antennae. Eyes composed of 20–26 ommatidia. Tergites smooth. Anterior corner of first coxal plate with enlarged margin and ‘striate’ appearance. Colour not preserved. Noduli laterales small, all near the posterior margin of the tergites and all at the same distance to the lateral margin.

First antenna three-jointed, third article approximately as long as first and second together, with two large apical aesthetascs and some (exact number could not be counted) smaller subapical aesthetascs. Second antenna about as long as pereiopod 7, with three-jointed flagellum. Apical cone is longer than third flagellar article, with only one small lateral sensillum. Flagellar articles 2 and 3 with a transverse ‘row’ of two (?) aesthetascs each.

Mandibles both with four-cusped pars incisiva, and a pars molaris represented by a tuft of hairy setae. Left mandible with larger, three (or 3.5)-cusped lacinia mobilis and two hairy setae on the hairy lobe. Right mandible with smaller, two-cusped lacinia mobilis and one hairy seta on the hairy lobe (broken off in the specimen after which the drawing has been prepared). Both mandibles with one hairy seta between the hairy lobe and the pars molaris. Beside this seta, there are some fine hairs. First maxilla lateral endite on the distal margin with lateral group of four stout, simple tooth setae, and a fifth seta that is slightly longer than half of the smallest of the larger four setae. Beside the latter, there is a slender seta. Mesal group of six more slender tooth setae, five of which are apically cleft. One small subapical seta on caudal face near mesal group of tooth setae. Mesal endite of first maxilla with two penicils, laterodistal end rounded. Second maxilla apically bilobate, mesal lobe slightly narrower than the lateral lobe. Mesal lobe with a marginal field of small sensory setae, two (or three?) small sensory setae between the lobes. Both lobes hairy. Maxilliped base with scale setae and with scales that are distinct in the proximal part, and that form a ‘sulcus lateralis’ (cf. Leistikow, 2001). Maxilliped palp three-jointed, the proximal article bearing only one large seta. Second article on mesal margin with proximal tuft of three or four small setae and distal tuft of numerous (> 15) small setae on a socket, beside which there are two small setae; on lateral margin with one slender and one broad seta. Distal article with distal tuft of numerous (> 20) small setae, three single small setae on the lateral margin and a longitudinal crest on the frontal face. Maxilliped endite rounded rectangular, with a stout seta on the caudal face, one small seta on the laterodistal corner, and a subapical penicil on the frontal/distal face; otherwise densely hairy.

Pereiopod 1 of male with antenna-grooming scalebrush on carpus and propodus. The part on the propodus consists of a scale-field occupying about half length of propodus, the part on carpus extends about half length of carpus and is somewhat oblique; distal margin is formed by a row of larger hyaline scales. Carpus also with scale-field on frontal face, along the ventral margin, merus with smaller scale-field along ventral margin. Male pereiopod 2 carpus with less dense scale-field on distal and ventral part of frontal face, and small group of scales on ventral face of merus. On all pereiopods, the largest, distal seta of the carpus is distinctly longer than half length of the propodus (0.65–0.75). Male pereiopod 7 base with several scale-rows, but no distinct groove, ischium with ventral margin almost straight, merus bearing a small lobe on the frontal face. Merus, ischium and carpus with distal scale-fields on the caudal face. Pereiopod dactyli with inner claw longer than outer claw, ungual seta with very acute tip, smaller seta beside the ungual seta, dactylar seta enlarged medially and fringed with long hairs in its distal half. One smaller seta each on frontal and caudal faces. Besides these setae, the proximal portion of the dactylus bears many long, tongue-shaped scales.

Pleopod exopodites 1 and 2 with with very narrow differentiation at lateral margin (probably vestigial respiratory fields). Pleopod exopodites 3–5 without distinct respiratory fields. Male pleopod 1 exopodite of nearly semicircular shape, with lateral margin straight, and few very small marginal setae on medial margin; endopodite twice as long as exopodite, its distal part very slender and slighly curved laterally. Row of small setae along the spermatic furrow (34 setae in the holotype). Male pleopod 2 exopodite only slightly shorter than endopodite, with hairy area along the median margin, and five marginal setae on the lateral margin; the distalmost seta is larger and spaced further than the others. Pleopod 3 exopodite with seven marginal setae, pleopod 4 exopodite with five marginal setae, the distal one larger. Pleopod 5 exopodite with two equally small marginal setae and broad transverse band of pectinate scales on the caudal face. Medial margin of male pleopod 5 exopodite simple, without any groove. Pleopod 3–5 endopodites distally concave.

Uropod sympodite laterally projecting beyond the insertion of the exopodite, laterodistally rounded. Beside exopodite, insertion with few gland pores (? not distinctly visible). Endopodite as long as exopodite, with inner face hairy, exopodite shorter than endopodite, elongate conical.

Differences from Scleropactoides guianensis are the linea supraantennalis, which is medially downcurved, and the less developed respiratory areas at the margins of pleopod exopodites 1 and 2.

Remark

The specimens were labelled as Scleropactes guianensis ( Van Name, 1936) , but this identification obviously had not been published.

The species curvatus, guianensis , curvatus and bonitanus are all very closely related. Future research may lead to the decision on whether they can be regarded as distinct species or whether they represent slightly different forms of one widespread species. On the basis of the available material, this cannot be decided, and I prefer to formally describe the above specimens as belonging to a new species. If the alternative interpretation proves to be correct, then the correct name will be Scleropactoides guianensis , and the other three will fall into its synonymy.

SCLEROPACTOIDES GUIANENSIS ( VAN NAME, 1936)

Figures

Figure 92. Scleropactoides curvatus sp. nov.: ♂ c. 10.5 × 5.0 mm, cephalothorax 2.57 mm wide, habitus and pleon dorsal, cephalothorax dorsal, frontal and lateral (Venezuela, Bolivar, leg. F. Yoris, 25 September 1967, MNRJ 9677).

Figure 93. Scleropactoides curvatus sp. nov.: ♂, c. 10.5 × 5.0 mm, cephalothorax 2.57 mm wide, mouthparts and first antenna (Venezuela, Bolivar, 118 km, leg. F. Yoris, 25 September 1967, MNRJ 9677).

Figure 94. Scleropactoides curvatus sp. nov.: ♂, c. 10.5 × 5.0 mm, cephalothorax 2.57 mm wide, pereiopods 1–3 frontal, pereiopod 1 dactylus caudal, uropod ventral (Venezuela, Bolivar, 118 km, leg. F. Yoris, 25 September 1967, MNRJ 9677).

Figure 95. Scleropactoides curvatus sp. nov. (Van Name, 1942): ♂, c. 10.5 × 5.0 mm, cephalothorax 2.57 mm wide, pereiopods 4–6 and dactylus 4 frontal, uropod dorsal (Venezuela, Bolivar, 118 km, leg. F. Yoris, 25 September 1967, MNRJ 9677).

Figure 96. Scleropactoides curvatus sp. nov.: ♂, c. 10.5 × 5.0 mm, cephalothorax 2.57 mm wide, pereiopod 7 frontal and caudal, second antenna (Venezuela, Bolivar, 118 km, leg. F. Yoris, 25 September 1967, MNRJ 9677).

Figure 97. Scleropactoides curvatus sp. nov.: ♂, c. 10.5 × 5.0 mm, cephalothorax 2.57 mm wide, pleopods 1–5 (Venezuela, Bolivar, 118 km, leg. F. Yoris, 25 September 1967, MNRJ 9677).