Strandesia sexpunctata Klie, 1932

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 : 27-30

Strandesia sexpunctata Klie, 1932 ( Figs 16–18)

Material examined. A few females from four localities (five samples): 1) a roadside canal, Muang district, Phitsanulok Province, 27 September 2005, coordinates: 16° 48´28.8˝ N and 100° 19´53.4˝ E (TH043); 2) Bung Sifai lake, Muang district , Pichit Province, 27 September 2005, coordinates: 16° 25´25.7˝ N and 100° 20´35.4˝ E (TH047); 3) Huai Pao river , Konsarn district , Chaiyaphum Province, 28 September 2005 (TH055), 9 October 2007 (TH152), coordinate: 16° 23´2.9˝ N and 101° 58´46.9˝ E; 4) Rice field, Konsarn district , Chaiyaphum Province, 9 October 2007, coordinates: 16° 23´2.9˝ N and 101° 58´46.9˝ E (TH153) .

Diagnosis. Carapace in lateral view elongated (length c. twice the height), dorsal margin slightly arched, bluntly angulated at c 4/5 of length, greatest height situated at c 1/3 of length; valve surface set with shallow pits; LV with internal groove along valve margin, with small antero-ventral inner list; RV with large marginal selvage on anterior margin; Wouters organ on A1 small, Rome organ long, aesthetasc ya on terminal segment markedly long; aesthetasc Y on A2 short; length of distal claws on penultimate segment c. 1.1 times of that of penultimate segment, aesthetasc y2 long; two large bristles on third endite of Mx1 serrated; d seta on T1 present; length of distal claw of caudal ramus c. 1/3 of that of ramus, distal seta c. 2/3 of that of distal claw, proximal seta long; 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. Strandesia sexpunctata Klie, 1932 is similar to S. complexa Victor & Fernando, 1981 . It can be distinguished from S. complexa by the absence of a lip-like flange, the more pointed posterior margin, the absence of tubercles on the external surface of the valves and by a shorter distal claw of the caudal ramus.

Measurements (in µ m). LV (n=1), L=736, H=352; RV (n=1), L=727, H=356.

Ecology. This taxon was previously found in ponds and ricefields ( Victor & Fernando 1981b). Several specimens were observed in our samples collected from lakes, roadside canals, rivers and also ricefields. It was recorded in pH ranges of 6.58–7.20 and a temperature range of 26.6–33.5° C.

Abbreviated redescription. Carapace in lateral view elongated, with length c. twice the height, dorsal margin slightly arched, bluntly angulated at c 4/5 of length, greatest height situated at c 1/3 of length, ventral margin slightly sinuous at 1/3 of length, anterior margin broadly rounded, posterior margin bluntly pointed; valve surface ( Fig. 16C–D) set with shallow pits.

Carapace in dorsal view subelliptical, LV overlapping RV along anterior, ventral and posterior margins.

LV in interior view ( Fig. 16A) elongated, with groove along valve margin, dorsal margin slightly arched, anterior margin broadly rounded, posterior margin bluntly pointed; inner lamella anteriorly broadly calcified, with short antero-ventral inner list, posteriorly more narrow.

RV in interior view ( Fig. 16B) with selvage along the margin, anteriorly large; inner lamella without inner list.

A1 ( Fig. 17A): first segment with small proximal Wouters organ, short dorso- lateral seta and two long, subequal ventro-apical setae; second segment with large and stout Rome organ and short dorso-apical seta; aesthetasc ya on terminal segment more than twice as long as short apical seta.

A2 ( Fig. 17B–C): exopodite with longest seta reaching slightly beyond middle of first endopodal segment; first endopodal segment with relatively short aesthetasc Y, natatory setae long, length of shortest c. 1/3 of that of penultimate segment, ventro-apical seta long (reaching tip of terminal segment); penultimate segment distally with three serrated claws (length c. 1.1 times of that of penultimate segment), aesthetasc y2 long (reaching beyond tip of terminal segment); terminal segment with 2 serrated claws, long g seta and aesthetasc y3, the latter c. 3/4 of accompanying seta.

Md-palp as in Fig. 17E–H. Md-coxa as in Fig. 17D.

Lateral subapical seta on basal segment of Mx1-palp ( Fig. 18A) long (reaching tip of terminal segment), two large bristles on third endite serrated, sideways directed setae on first endite unequal (short one c. 3/4 of that of long one).

T1 ( Fig. 18B–C) with a-, b- and d-setae present.

T2 ( Fig. 18D–E) with d1 2.4 times the length of d2.

T3 as in Fig. 18F–G.

Caudal ramus ( Fig. 18H) stout, with ventral margin serrated, distal and proximal claws long, serrated, length of distal claw c. 1/3 of that of ramus, distal seta long (c. 2/3 of that of distal claw), proximal seta long (almost reaching tip of ramus). Caudal ramus attachment ( Fig. 18H) stout, with Triebel’s loop situated at middle of distal part of main branch, dorsal and ventral branches well-developed.

Remarks. Strandesia sexpunctata Klie, 1932 appears to be a very rare species. We found only a few specimens in a roadside canal in Phitsanulok Province. This species was described from Java ( Klie 1932) and later reported from Sulawesi and Philippines ( Victor & Fernando 1981b). Thus far, there is no record of this species outside of Southeast Asia.

Genus Pseudostrandesia Savatenalinton & Martens, 2009