Parasterope singula, Pham & Karanovic, 2022

Pham, Huyen T. M. & Karanovic, Ivana, 2022, Four new Parasterope (Ostracoda, Myodocopina) from the Northwest Pacific and their phylogeny based on 16 S rRNA, ZooKeys 1095, pp. 13-42 : 13

Parasterope singula sp. nov.

Figs 8 , 9

Specimens examined.

Holotype female dissected on one slide, shells on SEM stub (NIBR IV 0000887835). Paratypes: two females dissected on one slide each, shells on SEM stub (NIBR IV 0000879835_2&3). The sample was collected from the type locality: South Korea, Chuja Island by Ho Young Soh on 29 November 2012 .

Etymology.

The name is a Latin noun, Parasterope singula , because only a female has been collected. The name is in nominative, feminine singular, agreeing in gender with the genus.

Diagnosis.

Surface of the shell completely smooth. Anterior end with a deep incisure and posterior infold of the carapace with a broad shelf. Posterior end wider than anterior. Dorsal margin rounded. Lateral eye well developed with black pigmented ommatidia. Uropodal lamellae with nine claws.

Description.

Female. Shell (Fig. 8 ). Carapace oval, broadening at posterior, greatest height near middle, carapace length 1.25 mm, height 0.9 mm. Carapace smooth and without ornamentation.

A1 (Fig. 8a ). 1st joint: with no hair on broad surface. 2nd joint: one spinous dorsal seta, one short lateral bristle, and small proximal dorsal spines. 3rd joint: seven setae (one short ventral and six dorsal). 4th joint: three bristles (one long dorsal bristle and two short ventral bristles). 5th joint: sensory bristle with six filaments without short proximal terminal. 6th joint: one medial seta, attached to bottom of 7th joint boundary. 7th joint: a-bristle claw-like, bare; b-seta with marginal filaments; c-seta with marginal filaments. 8th joint: d-bristle absent; e-bristle bare with blunt tip; f- and g-bristles with marginal filaments.

Bellonci orange (Fig. 9b ). Elongate with rounded tip with unclear constriction.

Eyes. Lateral eye with 18 ommatidia.

A2 (Fig. 9c, d ). Protopodite: rounded without medial bristle. Endopodite (Fig. 9c ): not strongly jointed, with long terminal bristle. Exopodite (Fig. 9d ): 9-jointed; bristle of 2nd segment along ventral margin and spines along dorsal margin reaching 8th joint; 3rd-8th joints with natatory hairs and spines along proximal part of ventral margin. 9th article: four bristles (two long natatory and two short bristles). 4th-8th joints with minute spines at inner terminal corner.

Md (Fig. 9e-g ). Coxale endite (Fig. 9e ) same as that on P. busanensis . Basale (Fig. 9f ): Basale endite with three spinous end bristles, four triaenid bristles with three spines excluding terminal pair, and two equal-length bare bristles. Basale dorsal margin with two long terminal setae, without mid-bristle; five rows of small spines on the broad surface near dorsal margin. Exopodite with hirsute tip and two small subterminal setae, exopodite almost same length as dorsal margin of first endopodite article. Endopodite (Fig. 9g ): 1st joint: ventral margin with three bristles (two long with long marginal spines, and one shorter without spine or hair); 2nd joint: ventral margin: with three terminal bristles; dorsal margin: with stout a-, b-, c-, and d-bristles and without bristle proximal to a-bristle; one long e-bristle between b- and c-bristles; four medial bristles forming an oblique row adjacent to c-bristle; f-bristle between c- and d-bristles, long, bare; g-bristle longer than f-bristle. 3rd segment with a strong dorsal claw-like bristle without marginal spines, three juxtaposed stout bristles of equal length, and two thin bristles.

Mxl. Endite I with three bristles. Endite II with three bristles. Basale: one dorsal medial distal bristle, two ventral medial proximal bristles. Endopodite: 1st with one short α-seta and one hairy β-seta; 2nd article with two terminal bristles.

L5 (Fig. 9h ). Ventral section with fan of long setae. Comb with spinous exopodal bristle just reaching past distal end of comb, one short slender bristle just ventral to base of stout bristle, one bristle near exopodal bristle stem, and four lateral bristles set back from edge at comb mid length.

L6 (Fig. 9i ). Unidentified number of endite bristle on the anterior margin. Lateral flap with hairs but no bristles. Anterior tip of skirt with two small bristles. Ventral and postero-ventral margin with 17 plumose bristles (one missing).

L7 (Fig. 9k ). Each limb with ten bristles. Four proximal and six distal bristles.

F (Fig. 9l ). Each lamella with six claws plus three posterior claws bristle-like. A total of nine claws and bristles.

Male. Not collected.

Remarks.

The presence of rows of small spines on the broad surface near the dorsal margin of the Md basale is a unique feature of Parasterope singula . Additionally, the number of bristles on the L7 (ten bristles: four on the terminal segment (two on each side), six on the proximal segments (three on each side) is less than in all other Parasterope representatives. The new species is similar to P. mckenziei , described from Samar Province, Philippines (McKenzie, 1970) but differs in the following characters: the Md endopodite is without a proximal bristle next to the a-bristle, a character not known in any other Parasterope , and the number of claws on UL (nine vs. seven).

The 2nd joint of the Md endopodite in P. singula carries one oblique row of cleaning setae, also recorded in P. antyx Kornicker, 1989 from Bay of Biscay (Kornicker, 1989), P. gamma Kornicker, Harrison-Nelson & Coles, 2007 from Hawaiian Islands ( Kornicker et al. 2007), P. hulingsi Baker, 1978 from California ( Baker 1978), P. jenseni from Sagami Sea, Japan ( Poulsen 1965), P. lagunicola Hartmann, 1984 from French Polynesia ( Hartmann 1984), P. mckenziei from the Philippines ( Kornicker 1970), P. muelleri Skogsberg, 1920 from England ( Poulsen 1965), P. prolixa Kornicker, 1975 from Australia ( Kornicker 1975), P. sequex Kornicker & Poore, 1996 from Australia ( Kornicker and Poore 1996), P. styx from Chile ( Kornicker 1975), and P. theta from Waikïkï ( Kornicker et al. 2007). The three other new species, P. busanensis , P. sagami , and P. sohi also have two oblique rows. The exopodite of the A2 in P. singula and P. sohi carries minute spines at inner terminal corner on the 5th-8th joints, while these spines are present from the 1st-8th joints in P. busanensis and P. sagami .

GenBank numbers 16S: OK048686, OK048687; 18S OK048723.

Figures

Figure 8. Light microscopy and scanning electron microscopy images of Parasterope singula sp. nov. holotype female adult: a Lateral view from left valve b Internal view from left valve c External view.

Figure 9. Parasterope singula sp. nov. holotype female adult: a A 1 b bellonci organ c A 2 endopodite d A 2 exopodite e Md basale and coxale endite f Md basale endite g Md endopodite h L 5 i L 6 k L 7 l F. Scale bar: 0.1 mm.