Parasterope busanensis, 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 busanensis sp. nov.

Figs 2 , 3 , 4

Specimens examined.

Holotype female dissected on one slide, shells on SEM stub (NIBR IV 0000879898_1). Paratypes: three males and one female dissected on one slide, shells on SEM stub (NIBR IV 0000879898_2;3;4 &5). All from the type locality: South Korea, Busan, Min-rack harbor (35°09'11.9"N, 129°07'38.4"E), collected by the Marin Biodiversity Institute of Korea (MABIK) on 11 April 2019 .

Etymology.

This species is named in reference to the type locality. It is used as an adjective for a place, with the Latin suffix - ensis.

Diagnosis.

Surface of the shell mostly smooth. Posterior infold of the carapace with a broad shelf. Dorsal margin rounded in both female and male. Posterior end clearly wider than anterior. Lateral eye well developed with black pigmented ommatidia. A1 8-segmented without d-bristle on the 8th joint. Uropodal lamellae with nine claws.

Description.

Female. Shell (Fig. 2a-f ) Carapace oval, broadening at posterior, greatest height near middle, carapace length 1.25 mm, height 0.94 mm. Nine small horn-like spines near dorsal margin. Posterior infold between broad list and valve margin without setae.

A1 (Fig. 3a ). 1st joint: with no hair on broad surface; longer than 2nd joint. 2nd joint: one spinous dorsal seta, one short lateral bristle, and three proximal dorsal spines. 3rd joint: seven setae (one short ventral and six dorsal). 4th joint: three bristles (one long dorsal and two short ventral bristles) and two small ventral spines at mid length. 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 with blunt tip; f- and g-bristles with marginal filaments.

Bellonci organ (Fig. 3b ). Elongate with rounded tip, constriction at mid-point.

Eyes. Lateral eye with many ommatidia obscured by black pigment; 13 ommatidia visible. Medial eye rounded and unpigmented.

A2. Protopodite: rounded without medial bristle. Endopodite (Fig. 3c ): 2-jointed with long terminal bristle. Exopodite: 9-jointed; bristle of 2nd segment with spinules 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). Articles 1-8 with minute spines at inner terminal corner.

Md (Fig. 3d ). Coxale endite ventral branch with spines forming four oblique rows. Basale endite with four spinous end bristles, three triaenid bristles with three or four pairs spines excluding terminal pair. Basale dorsal margin with two long terminal setae, without mid-bristle. Exopodite with hirsute tip and two small subterminal setae, exopodite almost same length as dorsal margin of first endopodite article. Endopodite: 1st joint: ventral margin with three bristles (one broken with short spines, one 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 one short bristle proximal to a-bristle; one long e-bristle and three medial bristles forming an oblique row between b- and c-bristles and adjacent to b-bristle; four medial bristles forming an oblique row adjacent to c-bristle; and one short bristle adjacent to d-bristle; f-bristle between c- and d-bristles, long, bare; g-bristle longer than f-bristle. End segment with a strong dorsal claw-like bristle without marginal spines, three juxtaposed stout bristles of equal length, and two thin bristles.

Mxl (Fig. 3e ). Endite I with three bristles. Endite II with three bristles. Basale: one bare proximal ventral bristle at the middle and four short distal ventral bristles. Endopodite: 1st article absent α-seta and one hairy β-seta; 2nd article with two terminal bristles.

L5 (Fig. 3f ). Ventral section with fan of long setae. Comb: spinous exopodite bristle over past distal end of comb, two short bristles (ventral to base of exopodite bristle) with bases almost on ventral edge of comb, four bristles just proximal at the ventral edge of comb, without bristle to base of exopodite bristle.

L6. Unknown

L7 (Fig. 3g ). Each limb with 12 bristles. Six proximal and six distal bristles (three on each side).

F (Fig. 3h ). Each lamella with six claws and three posterior claws bristle-like. A total of nine claws and bristles.

Male. All features are comparable to adult female; important differences are listed below.

Shell (Fig. 2g-i ). Carapace more elongate than that of female and with more open incisure, hairs forming vertical row near posterior end, carapace length 1.36 mm, height at middle 0.9 mm.

A1 (Fig. 4a ). Sensory seta with robust stem and many filaments. 7th and 8th joints with very long c- and f- setae (long as carapace length) each with numerous of marginal filaments. 2nd and 4th joints without dorsal margin spines.

A2 (Fig. 4b ). Endopodite with 3-jointed, article two with two lateral setae, article three recurved with 1 proximal seta.

Md (Fig. 4c ). Basale dorsal margin with one seta at mid-length. Endopodite: two relatively long bristles proximal to a-bristle.

Eyes (Fig. 4d ). Lateral eye with more than 17 ommatidia. Medial eye rounded and unpigmented.

Reproductive organs (Fig. 4f ). Copulatory limbs are coalesced proximally, in generally, shorter than the furca lamella. The lobe is distally subdivided into three small lobes.

Remarks.

The new species is closely related to P. iota Kornicker, Harrison-Nelson & Coles, 2007, described from Kapua Channel ( Waikïkï, Hawaii). The first joint of the A1 of P. busanensis is without hair on the broad surface, present in P. iota . In addition, the 3rd-8th joints of P. iota each have fairly stout proximal ventral spines, absent in P. busanensis . The distal margin of the Mxl of P. busanensis bears four bristles compared to two in P. iota , and three bristles (one minute) near the ventral margin rather than five in P. iota . The new species shares many characters with P. gamurru Syme & Poore, 2006 described from Queensland, Australia ( Syme and Poore 2006a), but lacks the nodes on the dorsal margin of the 5th joint on the A1, which is a prominent character of P. gamurru . The new species also bears two oblique rows of cleaning setae on the medial side of the Md 2nd joint, compared to only one in P. gamurru . The endite II of P. busanensis differs from that of P. pacifica Kornicker and Harrison-Nelson, 2005 from Johnston Atoll ( Kornicker and Harrison-Nelson 2005) in having three rather than four bristles. The 3rd joint of the Md in P. theta Kornicker, Harrison-Nelson & Coles, 2007 from Waikïkï, Hawaii ( Kornicker et al. 2007). The same character is present in P. sigma Kornicker, Harrison-Nelson & Coles, 2007 from Käneohe Bay, Hawaii ( Kornicker et al. 2007), and P. zeta Kornicker, 1986 from the Gulf of Mexico ( Kornicker 1986).

The sexual dimorphism found in the new species, the morphology of the dorsal mid-bristle on the basale of Md, and the number of bristles proximal to the a-bristle on the endopodite of the Md, have never been described in Parasterope .

GenBank numbers 16S: OK048681, OK048682; 18S: OK048719, OK048720.

Figures

Figure 2. Light microscopy and scanning electron microscopy images of Parasterope busanensis sp. nov. a-f holotype female adult: a External view b Lateral view from left valve c Spines on dorsal margin d Internal view of anterior part e L 5 ventral section f Internal view of posterior part g, h paratype male adult: g External view h Lateral view from right valve i Internal view of left valve.

Figure 3. Parasterope busanensis sp. nov. holotype female adult: a A 1 b Bellonci organ c A 2 d Md e Mxl f L 5 g L 7 h F. Scale bar: 0.1 mm.

Figure 4. Parasterope busanensis sp. nov. paratype male adult: a A 1 b A 2 c Md d Bellonci organ. Scale bar: 0.1 mm.