Strandesia perakensis 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 : 22-23

Strandesia perakensis Victor & Fernando, 1981 ( Figs 12–15)

Material examined. Two females from 2 samples: 1) one from Kwan Phayao lake, Muang district , Phayao Province, 24 September 2005, coordinates: 19° 09´32.6˝ N and 99° 54´36.2˝ E (TH028); 2) one from Mae Peum reservoir, Maejai district , Phayao Province, 7 October 2007, coordinates: 19° 21´28.6˝ N and 99° 51´44.6˝ E (TH143) .

Diagnosis. Carapace in lateral view subovate, greatest height situated in front of mid-length, anterior margin broadly rounded, posterior margin bluntly pointed; valve surface set with tiny shallow pits, spines and long setae; LV overlapping RV, LV slightly longer than RV anteriorly and posteriorly; LV with internal groove along valve margin, inner lamella without inner list; Wouters organ small, Rome organ short, aesthetasc ya on terminal segment longer than short apical seta on A1; aesthetasc Y on A2 long, aesthetasc y2 long; two large bristles on third endite serrated; d seta on T1 present; length of distal claw of caudal ramus c. half of that of ramus, distal seta short, proximal seta short; caudal ramus attachment stout, with Triebel’s loop situated at middle of distal part of main branch, dorsal and ventral branches well-developed.

Differential diagnosis. See differential diagnosis for Strandesia sanoamuangae sp. nov. (above).

Measurements (in µ m). LV (n=1), L=784, H=456; RV (n=1), L=754, H=460; Carapace (n=1), L=744, W=414.

Ecology. Victor & Fernando (1981b) found this species in ponds and in a marsh in Malaysia and Indonesia. The present study expands the range of ecological habitats in which this species can be found. It is encountered in lakes and man-made reservoirs with a pH range of 6.79–7.20 and a temperature range of 28.4– 30° C in our study.

Abbreviated redescription. Carapace in lateral view ( Fig. 12A) subovate, with length c. 1.8 times height, dorsal margin arched, greatest height situated in front of mid-length, ventral margin straight, anterior margin broadly rounded, posterior margin bluntly pointed; valve surface ( Fig. 12B) set with tiny shallow pits, spines and long setae.

A2 ( Fig. 14B–C): exopodite with longest seta reaching tip of first endopodal segment; first endopodal segment with long aesthetasc Y, natatory setae long, length of shortest c. 1/3 of that of penultimate segment, apical seta long (reaching tip of terminal segment); penultimate segment distally with three serrated claws (length c. 1.25 times of that of penultimate segment), aesthetasc y2 long (reaching beyond tip of terminal segment); terminal segment with two serrated claws, long g seta and aesthetasc y3, the latter c. 3/4 of accompanying seta.

Md-palp as in Fig. 14D–E. Md-coxa as in Fig. 14F.

Lateral subapical seta on basal segment of Mx1-palp short ( Fig. 15A), two large bristles on third endite serrated, sideways directed setae on first endite unequal (short one c. 2/3 of that of long one) ( Fig. 15 B).

T1 ( Fig. 15C–D) with a-, b- and d-setae present.

T2 ( Fig. 15E) with d1 c. 1.4 times as long as d2.

T3 ( Fig. 15F) as in Fig. 15F.

Caudal ramus ( Fig. 15G) stout, with ventral margin serrated, distal and proximal claws long, serrated, length of distal claw c. half of that of ramus, distal seta short (c. half of that of distal claw), proximal seta short (not reaching tip of ramus). Caudal ramus attachment ( Fig. 15H) stout, with Triebel’s loop situated at middle of distal part of main branch, dorsal and ventral branches well-developed.

Remarks. Victor & Fernando (1981b) described Strandesia perakensis Victor & Fernando, 1981 , based on material from Malaysia and Indonesia. The morphology of both valves and soft parts of Thai specimens corresponds to that of the type material. Strandesia perakensis is a rare species. We found only two specimens from two localities. These are the first records after the original description of this species.