Bradleytriebella lineata (Victor & Fernando, 1981)

Savatenalinton, Sukonthip & Martens, Koen, 2010, On the subfamily Cypricercinae McKenzie, 1971 (Crustacea, Ostracoda) from Thailand, with the description of six new species 2379, Zootaxa 2379, pp. 1-77 : 70-73

Bradleytriebella lineata (Victor & Fernando, 1981) ( Fig. 46)

1981 Strandesia lineata Victor & Fernando : 487, Figs 91–109.

2009 Bradleystrandesia lineata — Savatenalinton & Martens: 36.

2009 Paracypretta amati Martens — Savatenalinton & Martens: 36.

2009 Bradleytriebella lineata — Savatenalinton & Martens: 46.

Material examined. Many females from several samples (see Table 5).

Diagnosis. Carapace in lateral view subtriangular (length c. 1.5 times height), greatest height situated slightly in front of mid-length, dorsal margin highly arched, anterior and posterior margin broadly rounded; valve surface set with striations and dispersed tiny setae; carapace in dorsal view ovate, greatest width situated slightly behind mid-length, anterior extremity asymmetrical, with LV strongly overlapping RV, posterior extremity symmetrical, broadly rounded; LV slightly overlapping RV; LV with internal groove along valve margin, with one inner list; RV without selvage; Wouters and Rome organs on A1 long; aesthetasc Y on A2 long; two large bristles on third endite of Mx1 serrated; length of distal claw of caudal ramus slightly longer than half of that of ramus, length of proximal claw c. 2/3 of that of distal claw, distal seta short (c. 1/3 of that of distal claw), proximal seta short; caudal ramus attachment slender, with Triebel’s loop on dorsal branch, ventral branches thin, long.

Differential diagnosis. Bradleytriebella lineata (Victor & Fernando, 1981) is rather unique because of the valve ornamentation, mainly the striations, and cannot be confused with other species in this genus.

Measurements (in µ m). LV (n=1), L=590, H=365; RV (n=1), L=568, H=360; Carapace (n=2), L=579– 583, W=366–368.

Ecology. This species was previously recorded from lakes, ponds, washing pools and roadside ditches ( Victor & Fernando 1981b) as well as in temporary ponds in a temporary river of Chor Amat (Red Sea Hills, Sudan) ( Martens 1984). In the present study, several specimens of this species were found in 17 localities, ranging from lakes, man-made reservoirs, ponds, swamps, rivers, canals, ricefields and natural springs. It occurs in a pH range of 6.50–7.20 and a temperature range of 23.4–34.5° C.

Abbreviated redescription. Carapace in lateral view ( Fig. 46A) subtriangular (length c. 1.5 times height), greatest height situated slightly in front of mid-length, dorsal margin highly arched, anterior and posterior margins broadly rounded, ventral margin almost straight; valve surface set with striations and dispersed tiny setae ( Fig. 46B).

Carapace in dorsal view ( Fig. 46C) ovate, greatest width situated slightly behind mid-length, LV overlapping RV strongly at anterior side, and moderately along ventral and posterior margins.

Carapace in ventral view ( Fig. 46D): ventral margin of LV slightly sinuous at mid-length.

LV in interior view ( Fig. 46E) subtriangular, with groove along valve margin; calcified inner lamella anteriorly wide, with one inner list, posteriorly more narrow.

RV in interior view ( Fig. 46F) without selvage, ventral margin slightly sinuous at mid-length, inner lamella without inner list.

A1: first segment with long, tube-like proximal Wouters organ, long dorso-subapical seta and two unequal, long ventro-apical setae; second segment with long Rome organ and a short dorso-apical seta, aesthetasc ya on terminal segment shorter than short apical seta.

A2: longest seta of exopodite long (reaching far beyond tip of first endopodal segment); aesthetasc Y long, length of shortest natatory seta c. 1/4 of that of penultimate segment; distal claws on penultimate segment serrated, long (length c. 1.5 times that of penultimate segment), aesthetasc y2 long (reaching tip of terminal segment).

Basal segment of Mx1-palp with long subapical seta (reaching tip of terminal segment), two large bristles on third endite serrated, sideways directed bristles unequal, length of short one slightly less than half of that of long one.

T1 with a, b setae, without d-seta.

T2 with length of seta d2 c. 2/3 of that of d1.

Caudal ramus with ventral margin serrated, claws serrated, length of distal claw slightly longer than half of that of ramus, length of proximal claw c. 2/3 of that of distal claw, distal seta short (c. 1/3 of that of distal claw), proximal seta short (not reaching tip of ramus). Caudal ramus attachment slender, with Triebel’s loop on dorsal branch, ventral branches thin, long.

Remarks. The morphology on both valves and soft parts of the Thai specimens of Bradleytriebella lineata (Victor & Fernando, 1981) is almost identical to that of the original description, except for two aspects: 1) the length of some setae. This is to be expected as the type specimens (from the Phillipines) are all last juvenile stages, while the Thai specimens are all adult (for more discussion, see Savatenalinton & Martens 2009b). 2) the occurrence of the d-seta on T1. There is no d-seta on T 1 in our specimens, while Victor & Fernando (1981b) mentioned the presence of this seta in their original description. However, their illustration clearly shows that the last subapical seta of the T1-protopodite was misinterpreted as d-seta. Thus, the absence of this seta in Thai specimens seems to be the normal pattern in this species.

This species has thus far been recorded from the Philippines ( Victor & Fernando 1981b), Sudan ( Martens 1984) and Thailand ( Savatenalinton & Martens 2009b, this study).