Indiacypris chalakkudensis, George & Martens, 2004

George, Sunny & Martens, Koen, 2004, On the taxonomic position of Indiacypridinae (Crustacea, Ostracoda), with the description of a new species of Indiacypris Hartmann, 1964 from Chalakkudy River (Kerala, India), Journal of Natural History 38 (5), pp. 537-548 : 542-547

publication ID	https://doi.org/ 10.1080/0022293021000013870
DOI	https://doi.org/10.5281/zenodo.4675507
persistent identifier	https://treatment.plazi.org/id/03F587F6-FFE5-3341-9122-FF67FD10FD85
treatment provided by	Carolina
scientific name	Indiacypris chalakkudensis
status	sp. nov.

Treatment

Indiacypris chalakkudensis n. sp.

( figures 1E, I–K View FIG , 3–5 View FIG View FIG View FIG )

Type locality. Chalakkudy River , about 50 m downstream of the confluence of Kannankuzhi Thodu and the main river, Kerala, India .

Type material. All type specimens, along with the specimens of I. dispar , were collected with a hand net on 4 July 1999 from the benthic region along the river bank.

HOLOTYPE: a female, with soft parts dissected in glycerine in a sealed slide and with valves stored dry in a micropalaeontological slide (OC.2427). Most illustrations in the present paper are made from this specimen.

PARATYPES: one female (OC.2428) and two males (OC.2429, 2432) dissected and stored as the holotype; four females (OC.2430, 2431, 2433, 2434) and one male (OC.2439) stored dry in a micropalaeontological slide. Four females preserved in ethanol (OC.2426).

Deposition. All types specimens are presently curated in the Ostracod Collection of the Royal Belgian Institute of Natural Sciences (Brussels, Belgium) .

Derivation of name

The species is named after its type locality, the beautiful Chalakkudy River , Kerala, India .

Diagnosis

RV with anterior margin slightly produced and evenly rounded. LV with posterior margin nearly straight, not asymmetrically rounded as in the preceding species, posterior overlap L> R in dorsal and ventral views therefore less pronounced. Longest natatory seta on A2 (seta 3) reaching beyond tips of end claws, other seta reaching about halfway along the claws. Female T1 with palp with a very weak division. T2 with seta d1 about one-quarter of length of d2. T3 with length of penultimate segment approximately three times the maximal width. Caudal ramus with proximal seta inserted near the middle of the ramus. Prehensile palps (=T1 of male) asymmetrical, with distal segment of right palp sickle-shaped, wider; distal segment of left palp distally tapering, with apical crest on the distal margin, this margin indented near the attachment. Hemipenis with largest lobe boot-shaped, distal margin of lesser lobe straight.

Description of female

Valves strongly asymmetrical ( figures 1E, I View FIG , 3M, N, I View FIG ), with LV overlapping RV on all sides. RV ( figure 3D, E, H View FIG ) with anterior margin slightly produced and evenly rounded, without indentation, and with ventral margin straight. LV ( figure 3C, F, G View FIG ) with caudal and ventral margins nearly straight, calcified inner margins narrow, especially caudally.

Natatory setae on A1 ( figure 4A View FIG ) long, Rome organ small. Longest natatory seta (3) on A2 ( figure 4B, C View FIG ) reaching beyond tips of end claws, other setae reaching less than halfway along these claws; z-setae unequal, z1 being the largest and reaching beyond tips of end claws, shortest claws (z3) reaching middle of claws; claw Gm only slightly shorter than GM.

Md with coxa ( figure 4I View FIG ) well-developed. Palp ( figure 4D, D View FIG ∞) with alpha-seta with broad base and narrow tip; four plumose setae near the base of the elongated penultimate segment; gamma-seta small and not hirsute; terminal segment rectangular and with at least one claw-like seta, two long setae and short short setae.

Mx1 ( figure 4G View FIG ) with palp large, first segment distally widely dilated, with a group of four subapical lateral setae and two hirsute subapical medial setae; second segment short and broad, with three apical claws and four apical setae. Third endite with two unequal and smooth Zahnborsten.

T1 ( figure 5E, E View FIG ∞, F) with a stout base, set with rows of unequal setae, a respiratory plate with five plumose rays and a short palp, the latter with a weak division (or a chitinous fold?) and with one long apical seta, flanked on either side by a short seta.

T2 ( figure 5D View FIG ) with seta d1 about one-quarter of the length of seta d2; penultimate segment divided, end claw rather short.

T3 ( figures 5A, B View FIG ) with first segment carrying three setae, second segment with one long apical seta; penultimate segment approximately three times as long as its greatest width, distally clearly dilated, and with a medio-lateral seta; terminal segment well-developed and not fused, carrying two subequal apical setae and a slightly longer subapical seta.

Caudal ramus ( figure 4J View FIG ) with proximal seta inserted close to the middle of the ramus.

Description of male

Valves ( figures 1J, K View FIG , 3A–D, K, L View FIG ) equally asymmetrical as in the female, with roughly the same shape but significantly smaller. Most appendages as in the female, with the following exceptions.

A2 ( figure 5C View FIG ) with seta z3 transformed into a short claw, claw Gm on terminal segment about one-third of the length of GM.

Prehensile palps (=T1 of male) asymmetrical. Distal segment of right palp ( figure 5H View FIG ) sickle-shaped, and relatively wide with margins running parallel, apical sensory organ small, two short apical sensory organs on first segment, the latter subquadrate. Distal segment of left palp ( figure 5G View FIG ) subtriangular, distally tapering, with apical crest on the distal margin, this margin indented near the attachment; apical sensory organ even smaller than in right palp; first segment subquadrate, with two long apical setae.

Hemipenis ( figure 5F View FIG ) with largest lobe boot-shaped, with clear corner, not smoothly rounded; distal margin of lesser lobe straight, thumb-like expansion large, elongated; internal anatomy with an additional coil in the post-labyrinthal spermiduct.

Measurements (all in µm)

Female. RV: Le=862–880, H=449–478. LV: Le=904–952, H=495–5570. Cp: Le=909–925, W=288–301 (N =2).

Male. RV: Le=750–819, H=391–420. LV: Le=774–861, H=407–443. Cp: Le=817–855, W=263–269 (N =2).

Relationships

The new species is closely related to I. dispar , but can be distinguished from it by the morphology of the valve margins (see above), especially by the smoothly rounded anterior margin of the RV (without indentation) and the posterior margin of the LV (not produced), by the shape of the hemipenis lobes, with larger lobe boot-shaped (with evenly rounded heel in I. dispar ) and lesser lobe straight (concave in I. dispar ), of the prehensile palps, especially the right one (very narrow terminal segment in I. dispar ), and by the position of the proximal seta on the caudal ramus. Indiacypris chalakkudensis n. sp. can be clearly distinguished from I. luxata , especially by the shape of the penultimate segment of the T3 (which is much more elongated in I. luxata ) and by the shape of the hemipenis lobes (the largest is evenly rounded, the lesser lobe concave in I. luxata ).

Ecology

The new species is known from its type locality only, namely from shallow, sandy sediments of the Chalakkudy River. Although Hartmann (1964) initially stressed that I. dispar is most likely a subterranean species, he later also mentions that he found single specimens of it in ponds and rivers. The riverine habitat thus seems a likely habitat for a species of Indiacypris . Neale and Victor (1978) do not mention the habitat of I. luxata .