Bradleystrandesia weberi ( Moniez, 1892 )

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 : 64-69

Bradleystrandesia weberi ( Moniez, 1892) ( Fig. 42)

1892 Cypris weberi Moniez : 129, Figs 6–11.

1932 Eucypris weberi — Klie: 459.

1979 Strandesia weberi — Victor & Fernando: 7.

1979 Strandesia spinifera Hartmann — Victor & Fernando: 7.

2009 Bradleystrandesia weberi — Savatenalinton & Martens: 36.

Material examined. Many females from several samples (see Table 4).

Diagnosis. Carapace in lateral view elongated, greatest height situated at c. 1/3 of length, dorsal margin arched, anterior margin broadly rounded, with two spines on antero-dorsal margin of LV, posterior margin rounded, with one long spine at mid-height of RV; LV overlapping RV anteriorly; LV with internal groove along valve margin, with one inner list; RV with marginal selvage; Wouters and Rome organs on A1 long, aesthetasc ya longer than short apical seta; aesthetasc Y on A2 long; two large bristles on third endite of Mx1 serrated; d seta on T1 present; length of distal claw of caudal ramus c. 2/5 of that of ramus, length of proximal claw c. half of that of distal claw, distal seta less than half of that of distal claw, proximal seta short; caudal ramus attachment slender, with Triebel’s loop on dorsal branch, ventral branches slim, long.

Differential diagnosis. Bradleystrandesia weberi ( Moniez, 1892) is characterized by the presence of a posterior spine on the RV and two antero-dorsal spines on the LV. This species can not be confused with any other species in Bradleystrandesia . However, based on external morphology of carapace, Bradleystrandesia weberi is close to Bradleytriebella trispinosa (Pinto & Purper, 1965) . It can be distinguished by the generic characters and the different shape of valves and spines, as well as the morphology of soft parts.

Measurements (in µ m). LV (n=2), L=1140–1200, H=646–715; RV (n=2), L=1080–1170, H=632–677; Carapace (n=1), L=1020 (without spine), 1470 (with spine), W=448

Ecology. This species has so far been recorded from a wide range of habitats, including ponds, marshes, mining pools, ricefields, lakes, man-made reservoirs, swamps, rivers, canals and natural springs ( Victor & Fernando 1981b; this study). It was found in a pH range of 6.31–7.50 and a temperature range of 26.7–34.1° C.

Remarks: For drawings of limbs, see Keyser & Bhatia (1989).

Abbreviated redescription. Carapace in lateral view ( Fig. 42A) elongated, with length c. 1.8 times height (spines not included), greatest height situated at c. 1/3 of length, dorsal margin arched, anterior margin broadly rounded, with two spines on antero-dorsal margin of LV, posterior margin rounded, with one long spine at mid-height of RV, ventral margin almost straight; valve surface pitted ( Fig. 42A, C–D).

Carapace in dorsal view ( Fig. 42B) subelliptical, greatest width situated at mid-length, anterior extremity unequal, LV with two spines; posterior extremity unequal, RV with one long spine; LV overlapping RV anteriorly, ventrally and posteriorly.

LV in interior view ( Fig. 42E, G–H) elongated, with groove along valve margin, antero-dorsal margin with two (one long, one shorter) spines; calcified inner lamella wide anteriorly, with one inner list, posteriorly more narrow.

RV in interior view ( Fig. 42F) with marginal selvage, posterior margin with a long spine at mid-height; inner lamella without inner list.

A1: first segment with long dorso-subapical seta, two long ventro-apical setae, and long, tube-like proximal Wouters organ; second segment with long Rome organ and short dorso-apical seta, aesthetasc ya on terminal segment markedly long (more than twice the length of short apical seta).

A2: longest seta of exopodite reaching middle of first endopodal segment; aesthetasc Y slim, shortest natatory seta long (length c. 2/3 of that of penultimate segment); distal claws on penultimate segment serrated, long (length c. 1.2 times that of penultimate segment), aesthetasc y2 long (reaching tip of terminal segment).

Basal segment of Mx1-palp with short subapical seta (not reaching tip of terminal segment), two large bristles on third endite serrated, sideways directed bristles unequal, short one c. half of length of long one.

T1 with a, b, d setae.

T2 with d1 c. 1.8 times length of d2.

Caudal ramus with ventral margin serrated, claws serrated, length of distal claw c. 2/5 of that of ramus, length of proximal claw c. half of that of distal claw, distal seta less than half of length of distal claw, proximal seta short (not reaching tip of ramus). Caudal ramus attachment slender, with Triebel’s loop on dorsal branch, ventral branches slim, long.

Remarks. Bradleystrandesia weberi ( Moniez, 1892) was reported from Celebes ( Indonesia) ( Moniez 1892), Cambodia ( Hartmann 1964), India ( Victor & Fernando 1979), Malaysia, Indonesia and Philippines ( Victor & Fernando 1979, 1981b) and Thailand (this study). We here consider this species to be endemic to the Oriental region.

Genus Bradleytriebella Savatenalinton & Martens, 2009

Bradleytriebella decorata ( Sars, 1903)

( Figs 43–45)

1903 Cypris decorata Sars : 23, Pl. 2, Fig. 4.

1932 Eucypris decorata — Klie: 462.

1981 Strandesia decorata — Victor & Fernando: 477, Figs 39 –54.

2009 Bradleystrandesia decorata — Savatenalinton & Martens: 36.

2009 Bradleytriebella decorata — Savatenalinton & Martens: 46

Material examined. Eight females from 3 samples: 1) Maethang reservoir, 26 September 2005, coordinates: 18° 13´30.6˝ N and 100° 19´3.9˝ E (TH039); 2) Nong Naree swamp, Muang district, Phetchabun Province, 28 September 2005, coordinates: 16° 26´23.7˝ N and 101° 08´29˝ E (TH051); 3) Huai Prasatyai reservoir, Dankhuntod district , Nakhon Ratchasima Province, 10 November 2006, coordinates: 15° 07´22.7˝ N and 101° 33´22.8˝ E (TH119) .

Diagnosis. Carapace in lateral view subtriangular, greatest height situated at c. mid-length, dorsal margin highly arched, anterior and posterior margins broadly rounded; valve surface smooth, set with dispersed setae; carapace in dorsal view ovate, greatest width situated at mid-length, anterior extremity unequal with LV longer than RV, posterior extremity equal, rounded, LV overlapping RV; LV with internal groove along valve margin, with one inner list; RV without selvage; Wouters and Rome organs on A1 long, aesthetasc ya longer than short apical seta; aesthetasc Y on A2 long; two large bristles on third endite of Mx1 serrated; d seta on T1 absent; length of distal claw of caudal ramus c. 1.7 times that of ramus, length of proximal claw c. 2/3 of that of distal claw, both proximal and distal setae short; caudal ramus attachment slender, with Triebel’s loop on dorsal branch, ventral branches well-developed.

Differential diagnosis. Bradleytriebella decorata ( Sars, 1903) is similar to B. parva ( Hartmann, 1964) and B. umbonata (Victor & Fernando, 1981) . It can be distinguished from the former by the more tumid carapace, the morphology of the caudal ramus and by the absence of marginal setae on the ventral margin of LV and RV and from the latter by the absence of the tuberculate ornamentation and of marginal fine tubercles along anterior, posterior and ventral margins on both valves.

Measurements (in µ m). LV (n=3), L=599–614, H=351–378; RV (n=3), L=575–596, H=351–378; Carapace (n=3), L=563–608, W=330–371.

Ecology. Sars (1903) described this species from samples raised from dried mud, which were taken from fishponds and inundated ricefields. Subsequently, it was recorded fom ponds, marshes, man-made reservoirs, freshwater lagoons and ricefields ( Victor & Fernando 1981b). We found this species in two man-made reservoirs and a swamp in a pH range of 6.79–7.0 and a temperature range of 26.7–38.3° C.

Abbreviated redescription. Carapace in lateral view ( Fig. 43A) subtriangular (length c. 1.7 times height), greatest height situated at c. mid-length, dorsal margin highly arched, anterior and posterior margins broadly rounded, ventral margin slightly sinuous at mid-length; valve surface smooth, set with dispersed setae.

Carapace in dorsal view ( Fig. 43B) ovate, greatest width situated at mid-length, anterior extremity unequal, LV longer than RV, posterior extremity equal, rounded; LV overlapping RV along anterior, ventral and posterior margins.

LV in interior view ( Fig. 43D) subtriangular, with groove along valve margin; calcified inner lamella anteriorly wide, with one inner list, posteriorly more narrow.

RV in interior view ( Fig. 43E) without selvage, inner lamella without inner list.

A1 ( Fig. 44A): first segment with long, tube-like proximal Wouters organ, long dorso-subapical seta and two long ventro-apical setae; second segment with long Rome organ and short dorso-apical seta, aesthetasc ya on terminal segment long (slightly longer than short apical seta).

A2 ( Fig. 44B) with longest seta of exopodite reaching far beyond tip of first endopodal segment; aesthetasc Y long, length of shortest natatory seta c. 1/3 of that of penultimate segment; distal claws on penultimate segment serrated, long (length c. 1.4 times that of penultimate segment), aesthetasc y2 long (reaching tip of terminal segment).

Md-palp as in Fig. 44C–D, Md-coxa as in Fig. 44E.

Basal segment of Mx1-palp ( Fig. 44F) with long subapical seta (reaching tip of terminal segment), two large bristles on third endite serrated, sideways directed bristles unequal, short one slightly longer than half of long one.

T1 ( Fig. 45A) with a, b setae, without d-seta.

T2 ( Fig. 45B) with d1 c. 1.7 times length of d2.

T3 as in Fig. 45C–D.

Caudal ramus ( Fig. 45F) with ventral margin serrated, claws serrated, length of distal claw slightly more than half of that of ramus, length of proximal claw c. 2/3 of that of distal claw, distal seta short (c. 1/4 of that of distal claw), proximal seta short (not reaching tip of ramus). Caudal ramus attachment ( Fig. 45E) slender, with Triebel’s loop on dorsal branch, ventral branches well-developed.

Remarks. Bradleytriebella decorata ( Sars, 1903) was described from China ( Sars 1903). Subsequently, it was recorded from Java ( Klie 1932), Malaysia, Indonesia, Philippines ( Victor & Fernando 1981b) and now from Thailand. The identification of this species is hampered by the incomplete (re-) descriptions: only the carapace shape in dorsal and lateral view and the caudal ramus were illustrated in the original description. Whereas the specimens from Thailand are very similar to the type material in carapace shape, there are some small differences in the morphology of the caudal ramus: the proportion between the distal seta and the ramus is 1: 7 in the Thai specimens, while it is 1: 9 in Chinese specimens. In our specimens, the length of the distal seta is 1/4 of that of the distal claw, while it is 1/ 3 in Sars’s specimens. Additionally, the proximal claw is also slightly longer in the Thai specimens.