Parasterope gamurru, Syme, Anna E. & Poore, Gary C. B., 2006

Syme, Anna E. & Poore, Gary C. B., 2006, Three new ostracod species from coastal Australian waters (Crustacea: Ostracoda: Myodocopa: Cylindroleberididae), Zootaxa 1305, pp. 51-67 : 52-54

Parasterope gamurru new species

Figures 1 , 2

Material examined.— Holotype: NMV J53224 one adult female on slide; Paratype: NMV J53225 one adult male on slide.

Type Locality.—Patch Reef, Lizard Island, Queensland, Australia. 14°41.038' S, 145°27.003' E, 3 m. Collected by T. Oakley, using hand net while snorkeling. Collection date: 3 February, 2000.

Distribution.—Known only from type locality.

Diagnosis.—First antenna of adult female with 4 dorsal nodes on article 5.

Description.—Adult female. NMV J53224 . Carapace oval, broadening at posterior, inner end of incisur at valve midheight, carapace length 1.36 mm, height 0.89 mm. Rostrum with 20 setae anterior and dorsal to list, anteroventral infold with 30 setae between list and valve edge, list continuing ventrally to posterior where it has broad triangular setae with smaller setae placed between, and pores between list and valve margin; number of setae unable to be determined due to fragmentation of carapace. Selvage: fringe of hairs at inner end of ventral margin of incisur. Vestment: anterodorsal corner of vestment proximal to infold with clusters of spines.

First antenna: article 2 with 1 spinous dorsal seta and 1 lateral seta, small dorsodistal lateral spines. Article 3 with 1 short ventral seta and 6 dorsal setae (only 4 on left first antenna but this presumed aberrant). Article 4 with 1 dorsal seta and 2 ventral setae. Article 5 dorsal margin with 4 nodes; sensory seta with 0 short proximal and 6 terminal filaments. Article 6 with medial seta, 1.5x length of a­claw. Article 7 with a­claw, b­seta with 4 marginal filaments, c­seta with 4 marginal filaments. Article 8 with no d­seta, e­seta bare with blunt tip, f­seta bent dorsally with 3 marginal filaments, g­seta with 6 marginal filaments.

Second antenna: protopod with small distal medial seta. Endopod with only 1 suture visible, end article with terminal filament. Exopod: article 2 seta with short marginal spines, reaching article 9. Articles 4–9 with basal spines and long setae with long marginal spines. Article 9 also with 1 further long seta with long marginal spines, and 2 shorter setae.

Mandible: coxale endite with small seta at base of ventral branch, ventral branch with spines (longer at base), ventral margin of dorsal branch undulating, with rows of small serrations. Basale endite with 4 spinous end setae, 3 triaenid setae with 4 paired spines excluding terminal pair, 1 dwarf seta, and glandular peg. Basale dorsal margin with 2 long terminal setae, equilength. Exopod with hirsute tip and 2 subterminal setae, exopod length approximately 0.6 of dorsal margin of first endopod article. Endopod article 1 with 3 long ventral setae (1 with short spines, 2 with long spines). Endopod article 2: ventral margin with 3 long terminal setae with short spines, dorsal margin with stout a­, b­, c­, and dsetae, 0–1 slender seta proximal to a­seta (0 on left mandible, 1 on right mandible); medial side with 6 cleaning setae, and 1 g­seta at base of d­seta; lateral side with 1 long e­seta between b­ and c­ setae, and 1 long f­seta between c­ and d­ setae. Endopod article 3 with stout dorsal claw, 3 stout setae and 2 slender setae.

Maxilla (fourth limb): triangular epipod. Endites folded and obscured. Basale with 1 dorsal medial proximal seta, 1 dorsal medial distal seta, 1 ventral medial proximal seta, 1 long ventral lateral distal seta with spines. Endopod article 1 with short alpha seta and long beta seta. Endopod article 2 with long terminal seta.

Fifth limb: comb with long exopod seta. Comb folded; details of other setae uncertain. Sixth limb: anterior margin with seta at each endite suture, lateral flap of skirt with 2 setae, posteroventral margin with 13 setae with spines. Seventh limb: with 12 setae, each with 3– 4 bells. Combs forming obtuse angle.

Furca: each lamella with 8 claws and setae decreasing evenly in size, and 1 lateral seta pointing posteriorly. Posterior of body: fragmented, but appears rounded and hirsute. No obvious thumb­like process. Reproductive organs: presence/absence unable to be determined. Bellonci organ and medial eye: presence/absence unable to be determined. Lateral eye: with 12 visible ommatidia, darkly pigmented. Lips: upper and lower lips hirsute lobes, upper lip with lateral spine. Gills: well developed, number of pairs unable to be determined.

Adult male. NMV J53225 . All features compared to adult female; important differences noted here: carapace length 1.18 mm, height at middle 0.68 mm. Posterior row of hairs present. First antenna: sensory seta with robust stem and many filaments. Articles 7– 8 with very long c­ and f­ setae (twice length of first antenna) each with approximately 30 marginal filaments. Second antenna: endopod with 3 articles. Article 2 with 2 lateral setae, article 3 recurved with 1 proximal seta. Mandible basale dorsal margin with 1 seta at midlength. Lateral eye with 20 ommatidia. Reproductive organs: presence/absence unable to be determined.

Remarks.—The presence of nodes on the dorsal margin of article 5 of the first antenna is unusual for females in this family (males often have a “bumpy” dorsal margin on articles 5 and 6). Parasterope gamurru can be distinguished from all other species in the genus by this feature. The only other species in the family with nodes (on females) are Amboleberis americana ( Mller, 1890) (with 4–6), Amboleberis cubensis Lalana & Kornicker, 1997 (with 7–8), and Dolasterope johanseni Poulsen, 1965 and species of Tetraleberis Kornicker, 1981 (all with 1 node).

The male described here is similar to males of several other known species in the genus but is assumed to be conspecific with the female, as it was found in the same sample and is morphologically similar. It differs from the female in the presence of 1 seta at midlength on the dorsal margin of the mandible basale; sexual dimorphism of this character is known in many species.

Species of Parasterope are known from most oceans and depths (excluding the Arctic). Although species have been described from the Indo –Pacific ( Kornicker, 1970; Poulsen, 1965) and the southeastern coastline of Australia ( Kornicker & Poore, 1996), none have been described from Queensland. P. gamurru extends the Australian distribution of this genus.

Etymology.—“ Gamurru ” is an Australian aboriginal word from the Yolnu language of northern Australia, meaning “nose” or “point,” in reference to the nodes on the first antenna for this species.

Figures

FIGURE 1. Parasterope gamurru, new species, adult female holotype NMV J 53224; A, carapace; B, first antenna, right, l. v. (122 X); C, second antenna, left, l. v. (109 X); D, mandible, left, l. v., bases of dorsal setae on basis and of all endopodial ventral setae represented by circles, medial cleaning setae not shown (157 X); E, coxale endite of right mandible, m. v. (118 X); F, maxilla, right, l. v. (165 X); G, fifth limb comb (165 X); H, sixth limb, right, l. v. (100 X); I, seventh limb (126 X); J, furca, left lamella, l. v. (61 X); K, upper and lower lips, d. v. (98 X); L, lateral eye (139 X).

FIGURE 2. Parasterope gamurru, new species, adult male paratype NMV J 53225; A, carapace; B, first antenna, filaments on sensory seta not shown, c­ and f­ setae full length not shown, left, l. v. (140 X); C, second antenna endopod, left, m. v (193 X).