Pseudostrandesia mamarilorum (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 : 54-59

Pseudostrandesia mamarilorum (Victor & Fernando, 1981) ( Figs 35–37)

1981 Strandesia mamarilorum Victor & Fernando : 490, Figs 110–126.

2009 Pseudostrandesia mamarilorum — Savatenalinton & Martens: 19.

Material examined. Many females from several samples (see Table 3).

Diagnosis. Carapace in lateral view subelliptical (length c. 1.7 times height), greatest height situated slightly in front of mid-length, anterior and posterior margins broadly rounded; LV considerably overlapping RV anteriorly; valve surface weakly reticulated and set with dispersed setae; carapace in dorsal view subelliptical, with greatest width situated at mid-length; LV with internal groove along valve margin, with one inner list; RV with marginal selvage; A1 with Wouters organ small, Rome organ long, aesthetasc ya as long as short apical seta on terminal segment; two large bristles on third endite of Mx1 serrated; d seta on T1 absent; length of distal claw of caudal ramus less than half of that of ramus, distal seta c. 9/10 of length of distal claw; caudal ramus attachment with Triebel’s loop situated at middle of distal part of main branch, dorsal and ventral branches well-developed.

Differential diagnosis. Pseudostrandesia mamarilorum (Victor & Fernando, 1981) is closely related to P. thailandensis sp. nov. The species is characterized by a large anterior L/R overlap, a small posterior overlap, a rounded, symmetrical carapace in frontal view, a reticulated valve surface and a long proximal seta of the caudal ramus (reaching slightly beyond tip of ramus).

Measurements (in µ m). LV (n=3), L=1030–1050, H=596–602; RV (n=3), L=991–1010, H=585–594; Carapace (n=3), L=997–1010, W=577–599.

Ecology. The range of habitat types of this species is broad. It was recorded from ponds, ricefields, marshes, streams and lakes ( Victor & Fernando 1981b). It is now also found in man-made reservoirs, swamps, rivers, canals and natural springs (this study). The species’ range of pH and temperature are 6.31– 7.40 and 26.7–33.5° C, respectively.

Abbreviated redescription. Carapace in lateral view ( Fig. 35A) subelliptical (length c. 1.7 times height), dorsal margin arched, greatest height situated slightly in front of mid-length, anterior and posterior margins broadly rounded, ventral margin straight, LV large overlapping RV anteriorly. Valve surface reticulated and set with dispersed setae ( Fig. 35B).

Carapace in dorsal view ( Fig. 35C) subelliptical, with greatest width situated at mid-length, anterior extremity unequal, LV longer than RV anteriorly.

Carapace in posterior view ( Fig. 35E) rounded, LV slightly larger and lower than RV.

LV in interior view ( Fig. 35F) subelliptical, with groove along valve margin, greatest height situated slightly in front of mid-length, anterior margins broadly rounded, posterior margin more narrowly rounded; anterior calcified inner lamella wide, with one inner list, posterior calcified inner lamella more narrow.

RV in interior view ( Fig. 35G) with marginal selvage, without inner list, ventral margin slightly sinuous at third anterior.

A1 ( Fig. 36A): first segment with small proximal Wouters organ, short dorso-subapical seta, two long ventro-apical setae; Rome organ on second segment long; aesthetasc ya on terminal segment as long as short apical seta.

A2 ( Fig. 36B–C) with longest seta of exopodite short (length c. half of that of first endopodal segment); aesthetasc Y slender and long; natatory setae long, length of shortest seta c. 1/4 of that of penultimate segment; penultimate segment distally with 3 serrated claws (c. 1.1 times length of penultimate segment), aesthetasc y2 almost reaching tip of terminal segment.

Md-palp as in Fig. 36E–F, Md-coxa as in Fig. 36D.

Basal segment of Mx1-palp ( Fig. 37A) with long subapical seta (reaching beyond tip of terminal segment), two large bristles on third endite serrated, sideways directed bristles on first endite unequal, length of short one c. 2/3 of that of long one.

T1 ( Fig. 36G) with a-, b- setae, but without d-seta.

T2 ( Fig. 37B) with seta d1 c. 1.4 times as long as d2.

T3 as in Fig. 37C–D.

Caudal ramus ( Fig. 37F) stout, ventral margin moderately serrated, both proximal and distal claws serrated, length of distal claw less than half of that of ramus, proximal claw c. 3/4 of length of distal claw, distal seta long (c. 9/10 of length of distal claw), proximal seta considerably large, reaching slightly beyond tip of ramus. Caudal ramus attachment ( Fig. 37E) stout, with Triebel’s loop situated at middle of distal part of main branch, dorsal and ventral branches well-developed.

Remarks. Pseudostrandesia mamarilorum (Victor & Fernando, 1981) was previously recorded from the Philippines, Malaysia and Indonesia ( Victor & Fernando 1981b). In this study, we found this species in several localities. The morphology of valves and limbs of the Thai specimens corresponds to that of material from the Philippines, Malaysia and Indonesia, except for the d seta on T1, which is absent in our material, present in Victor & Fernando’s material. We here decide that the absence of this seta seems to be the normal pattern in this species as the last subapical seta of the T1-protopodite was misinterpreted as d-seta in their illustration.

Genus Bradleycypris McKenzie, 1982