Vestalenula, 2003

Pinto, R. L., Rocha, C. E. F. & Martens, K., 2003, On two new species of the genus Vestalenula Rossetti & Martens, 1998 (Crustacea, Ostracoda, Darwinulidae) from semiterrestrial habitats in São Paulo State (Brazil), Zoological Journal of the Linnean Society 139, pp. 305-313 : 306-308

VESTALENULA BOTOCUDA SP. NOV.

( FIGS 1A–E , 3I–P )

Type locality

Sítio da Colônia, Mulungu, near Araçoiaba da Serra, São Paulo State, Brazil. Approximate GPS coordinates: 23∞32¢2≤S, 47∞39¢ 41.1≤W.

Muddy patches in a dry streamlet in a rain forest remnant. The mud was moist at the time of collecting; during wet season standing or running water might be present. Material collected on 15.08.2001 by CEFR and RLP.

Type material

Holotype: an ovigerous, dissected female, with valves stored dry in a micropalaeontological slide and dissected soft parts kept in a sealed slide ( MZUSP 15041).

Paratypes: an ovigerous female dissected and stored like the holotype ( MZUSP 15043); 2 ovigerous, dissected females, with valves used for SEM and stored in micropalaeontological slides, and dissected soft parts kept in sealed slides ( MZUSP 15042, MZUSP 15044); 3 carapaces used for SEM and stored in micropalaeontological slides ( MZUSP 15045, MZUSP 15046, MZUSP 15047); 4 ovigerous females kept in toto in ETOH ( MZUSP 15048).

Derivation of name

Botocudos is the designation of several South American Indian tribes that use a device to enlarge the lower lip. The present species is characterized by the fact that the LV forms an enlarged anterior ‘lip’, greatly overlapping the RV.

Abbreviated diagnosis

Valves elongated (L/H = c. 2.1), with straight parts of dorsal margin slightly sloping towards the front; anterior overlap LV> RV unusually pronounced and typical; ms relatively large; keel on RV short and rounded and positioned rather posteriorly; third segment of A1 with ventro-apical seta. First endopodal segment of A2 with 2 apical setae; seta z on penultimate segment claw-like. Md-palp with seta x longer than w.

Description

Cp ( Fig. 3I- P ) with whitish, smooth surface covered with long, widely spaced setae; elongated, in lateral view, with straight parts of dorsal (c. 30% of total length) and ventral (c. 55%) margins subparallel, dorsal margin slightly sloping. LV overlapping RV along anterior, ventral and posterior margins; anterior overlap very pronounced, LV extending significantly beyond RV. Both valves asymmetrical in dorsal and ventral views, widest in the posterior quarter of the carapace, LV bulging over RV on the posterior side, anteriorly extending significantly beyond RV; central part with a weak constriction. Ventral margin in ventral view strongly sinuous; keel short and rounded, effectively blocking LV in tightly closed carapaces.

LV in lateral (internal) view with caudal margin nearly evenly rounded, slightly everted towards the dorsal side, anterior margin everted towards the ventral side; anterior internal tooth short and small, situated c. 15% of total length from the anterior margin; ms large, positioned nearer the anterior side and consisting of c. 8 scars arranged in a rosette; mandibular scar rounded.

RV in lateral (internal) view with caudal margin asymmetrically twisted, ventrally everted towards the median rather than dorsal side, anterior margin everted towards the ventral side; postero-ventral keel short and rounded, situated rather posteriorly, ms large, situated nearer the anterior side, consisting of c. 8 scars arranged in a rosette.

Both valves with an internal rim along the anterior margin (= calcified inner margin?); in LV this rim seals the closure of the carapace when overlapping the RV.

A1 ( Fig. 1A ). First segment stout with dorsal seta, the second with 2 unequal ventral setae (one c. 2.5 times as long as the other); third segment with 1 ventral and 1 dorsal setae (s 1); fourth segment with 1 dorsal seta (s 2) and small alpha-seta; fifth podomere bearing 4 apical setae, 2 subequal, ventral setae (with an alpha-seta near their insertion) and 2 longer ones in dorsal position; last podomere with subapical aesthetasc, 2 long apical setae, the ventral seta about half as long as the dorsal, and a dorso-apical ‘alpha’ seta.

A2 ( Fig. 1B ). Protopodite two-segmented, first segment with 2 setae and dorsal hook (h), second segment with long seta. Exopodite (exo) with long, apical seta and short, lateral conical spine. Endopodite three-segmented; first podomere with ventral aesthetasc clump (Ac) in proximal position and 2 setae on the expanded ventro-apical corner; second podomere with 2 ventral aesthetascs (y 1 and y 2) and short, claw-like ventro-apical seta (t), subapical seta (z) and 4 distal claws: 2 long, 1 intermediate and 1 short (x); third endopodite short and slender, with one ventral aesthetasc (y 3) and 2 apical claws, one short and about half the length of the second one, the latter reaching beyond the tips of the long claws of the penultimate segment.

Md with palp ( Fig. 1C ) three-segmented, consisting of basis and two-segmented endopodite; basis typical of Darwinulidae , i.e. set with branchial plate and fan of large setae (possibly used in filter-feeding – not illustrated). First podomere of endopodite distally widened, medial seta x about 1.5 times as long as the external, subapical seta (w); two internal setae present: y very short, z very long, reaching halfway the apical claws on the terminal segment; this podomere narrow, with 5 apically hirsute, unequal claws (3 long, 1 intermediate, 1 short), 1 short internal seta (c), and a subapical external seta (b).

Mx (not illustrated). Palp two-segmented; proximal segment with an external, subapical seta, 3 terminal setae (2 straight and 1 curved, the latter shorter and plumose), and 2 short setae inserted on either side of the terminal segment; terminal segment small, with 1 thin median seta and 2 subequal, stout setae set with a double row of setulae.

T1 (not illustrated). Protopodite with branchial plate, 2 isolated, unequal setae close to the articulation with the endopodite. Three-jointed endopodite; first segment with 2 subapical setae; second segment with 1 subapical seta; third segment smaller, with 2 lateral, subequal setae and a strong terminal claw.

T2 (not illustrated). Protopodite one-segmented, rather stout, with 3 ventral setae, 1 short proximal and 2 long, unequal distal ones. Endopodite four-segmented; first segment with 2 unequal ventro-apical setae and 1 long seta, slightly exceeding the tip of the next segment; second and third segment with 1 stout ventro-apical seta each; terminal segment short, with 1 strong apical claw, flanked by 2 subapical claws, the ventral longer than the dorsal one.

T3 (not illustrated). Protopodite one-segmented, short, with 2 unequal ventro-apical setae. Endopodite four-jointed; first segment with 1 distal seta approximately as long as the segment itself; second and third segments bearing 1 apical seta each, reaching beyond the tip of the next segment; fourth segment with a long, curved apical claw and 2 subapical setae, the ventral longer than the dorsal one.

Caudal rami consisting of a slender base, a shorter proximal and a longer apical seta. Postabdomen elongated, lobed and twisted, and bearing a long subapical seta ( Fig. 1D, E ).

Measurements

L = 540–560 Mm; H = 250–260 Mm (n = 3)

Ecology and distribution

Thus far, the species is known from its type locality only, where it occurs on patches of moist mud in a remnant of the Atlantic Forest in south-eastern Brazil.

Differential diagnosis

This species is at once recognizable by its unique combination of valve and soft part characters, namely short anterior tooth on the LV and the short keel on the RV, typical of the pagliolii -lineage, and the postabdomen with seta, thus far only found in a representative of the danielopoli -lineage. The large anterior LV> RV overlap is unique amongst extant Darwinulidae .

Figures

Figure 1. Vestalenula botocuda sp. nov. A. A1, lv (MZUSP 15044). B. A2, lv (MZUSP 15041). C. Md-palp, lv (idem). D. CR and postabdomen, vv (MZUSP 15042). E. CR and postabdomen, lv (MZUSP 15041). Scale bars = 20 Mm.

Figure 3. A-H: Vestalenula irajai sp. nov. I-P: Vestalenula botocuda, sp. nov. A. LV, iv (MZUSP 15052). B. RV, iv (idem). C. LV, iv, detail of ms (idem). D. LV, iv, detail of anterior tooth (arrow) (idem). E. RV, iv, detail of ms (idem). F. RV, iv, detail of posterior keel (arrow) (idem). G. Cp, dv (MZUSP 15054). H. Cp, right lv (MZUSP 15053). I. Cp, right lv (MZUSP 15045). J. LV, iv (MZUSP 15042). K. RV, iv (idem). L. Cp, dv, detail of anterior overlap (MZUSP 15046). M. Cp, right lv, detail of anterior overlap (MZUSP 15045). N. Cp, vv, detail of posterior tooth (arrow) blocking LV (MZUSP 15047). O. RV, iv, detail of posterior keel (arrow) (MZUSP 15042). P. Cp, dv (MZUSP 15046). Scale bars: A, B, G-K, P = 100 Mm; F, L-O = 20 Mm; C-E = 10 Mm.