Cylindroleberis marranyin, 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 : 61-66

Cylindroleberis marranyin new species

Figures 5 , 6

Material examined.— Holotype: NMV J53214 one adult female, appendages on slide, body and valves in alcohol; Paratypes: all with appendages on slide, body and valves in alcohol; NMV J53215 one adult male; NMV J53216 one A­ 2 female, NMV J53217 one A­ 2 female; NMV J53218 one A­ 3 female, NMV J53219 one A­ 3 female; NMV J53220 one adult male; NMV J53221 one A­ 1 male.

Type Locality:—Sandy Point, Western Port, Victoria, Australia. 38º 24' S, 145º 14' E, benthic, 4 m. Collected by A. Syme using epibenthic sled. Collection date: 20 April 2004.

Distribution:—Known only from type locality.

Diagnosis.—Mandible basale dorsal margin with no setae at midlength; maxilla proximal endite with 2 long setae; sixth limb with four anteroventral setae; 10 furcal claws and setae.

Description.—Adult female. NMV J53214 . Carapace elongate with slightly convex ventral and dorsal margins, posterior evenly rounded, inner end of incisur at valve midheight, carapace length 1.67 mm, height 0.73 mm. Rostrum with 15 setae anterior and dorsal to list, anteroventral infold with 12 setae between list and valve edge, list continuing ventrally to posterior where it has broad triangular setae with smaller setae placed between, number of setae unable to be determined due to fragmentation of carapace. No selvage observed. No spines seen at anterodorsal corner of vestment proximal to infold.

First antenna: article 2 with 1 spinous dorsal seta and 1 lateral seta. Article 3 with 1 short ventral seta and 6 dorsal setae. Article 4 with 1 dorsal seta and 2 ventral setae. Article 5 with sensory seta with 1 short proximal and 6 terminal filaments. Article 6 with medial seta, 1.5x length of a­claw. Article 7 with a­claw, b­seta with 2 marginal filaments, c­seta with 2 marginal filaments. Article 8 with no d­seta, e­seta bare with blunt tip, f­seta bent dorsally with 4 marginal filaments, g­seta with 2 marginal filaments.

Second antenna: protopod with no distal medial seta. Endopod with only 1 suture visible, end article with terminal filament. Exopod: article 2 seta with short marginal spines, reaching ninth article. Articles 3–9 with basal spines and long setae with long marginal spines. Article 9 also with 2 shorter seta and 1 medium seta.

Mandible: coxale endite with small seta at base of ventral branch, ventral branch with spines (longer at base), ventral margin of dorsal branch undulating, spines at ventral corner of triangular tip, seta present on dorsal margin. Basale endite with 4 spinous end setae, 2–3 triaenid setae with 5 paired spines excluding terminal pair, 2 dwarf setae of unequal length and glandular peg. Basale dorsal margin with 2 long terminal setae, equilength. Exopod with hirsute tip and 2 subterminal setae, exopod length approximately 0.25 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, 1 slender seta proximal to a­seta; medial side with 6 cleaning setae; lateral side with 1 long f­seta between c­ and dsetae. Endopod article 3 with stout dorsal claw, 3 stout setae and 2 slender setae.

Maxilla (fourth limb): epipod reaching near to middle of basale. Endite I with 1 short and 2 long setae, endite II with 3 long setae. Basale with 1 lateral proximal seta at midheight, 1 proximal ventral seta, 1 long spinous ventral terminal seta, dorsal margin with 1 distal seta. Endopod article 1 with short alpha seta and long beta seta. Endopod article 2 with long terminal seta.

Fifth limb comb folded and partly obscured, long exopod seta present and 1 shorter lateral seta visible near ventral margin of comb. Sixth limb: anterior margin with seta at each endite suture, lateral flap of skirt with 4 setae, ventral margin with 10 setae with spines, posteroventral corner with 2 setae with spines. Seventh limb: with 12 setae, each with 3–5 bells. Combs forming obtuse angle, each comb with 6 teeth.

Furca: each lamella with 8 claws and setae decreasing evenly in size, and 1 lateral seta. Bellonci organ and medial eye: presence/absence unable to be determined. Lateral eye: with 9 visible ommatidia. Lips: presence/absence unable to be determined. Posterior of body: features unable to be determined. Reproductive organs: presence/absence unable to be determined. Gills: approximately 6 pairs, well developed.

Female, A­2 stage. NMV J53216 . First antenna and seventh limb compared to adult female; important differences noted here: Carapace length 1.39 mm, height 0.63 mm. Similar to adult female, except s­seta with 0+6 filaments. No obvious embryos, and slight tapering of setae on seventh limb.

Female, A­3 stage. NMV J53218 . First antenna and seventh limb compared to adult female; important differences noted here: Carapace length 1.17 mm, height 0.51 mm. First antenna article 3 with 3 dorsal setae; s­seta with 0+6 filaments. Seventh limb with only 10 setae.

Adult male. NMV J53215 . All features compared to adult female; important differences noted here: carapace length 1.98 mm, height 0.88 mm. Posterior row of hairs present. First antenna: article 5 with proximal protuberance (visible from medial side), sensory seta with robust stem and many filaments. Articles 7–8 with very long c­ and fsetae (twice length of first antenna) each with 30 marginal filaments, g­seta with 9 marginal filaments. Second antenna: endopod with 3 articles. Article 2 with 3 setae, article 3 recurved with 1 proximal seta. Mandible endopod article 2 with 2 proximal setae. Fifth limb with long exopod seta, 2 short seta near base of exopod seta, and 4 shorter lateral setae near ventral margin of comb. Furca: each lamella with 9 claws and setae decreasing evenly in size, and 1 lateral seta pointing posteriorly. Lateral eye: with 23 ommatidia. Reproductive organs: presence/absence unable to be determined. Posterior of body: features unable to be determined.

Male, A­1 stage. NMV J53221 . All features compared to adult female; important differences noted here: Carapace length 1.46 mm, height 0.61 mm. First antenna s­seta with 1+6. Second antenna endopod with bare second article, article 3 not recurved, with 1 seta and terminal peg.

Remarks.— The most useful starting feature to differentiate species of Cylindroleberis is the number of setae at midlength on the dorsal margin of the mandible basale. In this respect, with no setae at this position, Cylindroleberis marranyin is similar to C. variabilis Kornicker, 1970 ( Indo –Pacific) but is larger (adult female 1.67 mm compared to 1.40 mm), and has only 2 (not 3) setae on the proximal endite of the maxilla. C. marranyin is also similar to C. nodulifera ( Poulsen, 1965) , a species only described from males in the Red Sea, but is larger (adult male is 1.98 compared to 1.50 mm) and has 10 (not 8) furcal claws and setae. C. marranyin is also similar to C. grimaldi vicina ( Skogsberg, 1920) but has fewer anteroventral setae on the sixth limb (4 compared to 7).

C. marranyin can be distinguished from C. grimaldi grimaldi ( Skogsberg, 1920) , C. bacescui Kornicker & Caraion, 1974 , C. verrucosa ( Poulsen, 1965) , C. vix Kornicker, 1992 , C. kliei Kornicker, 1976 , C. thailandica ( Poulsen, 1965) , C. minuta ( Poulsen, 1965) and C. vibex Kornicker, 1992 all of which have 1 or more dorsal setae at midlength on the mandible basale.

Cylindroleberidid instars have been discussed by Hiruta (1979) and Kornicker (1981, 1992). Instars are labelled from A­1 (Adult minus 1), A­2, and so on towards younger stages; or, from instar 1 upwards. Instars for Cylindroleberis have been described for C. vibex ( Kornicker, 1992) and C. variabilis ( Kornicker, 1991) . After a comparison with these descriptions, the female instars here have been assigned to the stages A­2 and A­3.

G, first antenna, right, l.v. (123X); H, second antenna endopod, right, l.v (168X).

The female A­1 stages of C. variabilis ( Kornicker, 1991) and C. vix have an s­seta with configuration 1+6. This instar is thus characterized by the presence of a proximal filament on the s­seta, a feature also present in the adult. The larger juvenile instar of C. marranyin corresponds more closely to features described for A­2 of C. vibex ( Kornicker, 1992) : s­seta with configuration 0+6 and seventh limb with 12 setae. We assign this then to A­2 and the smaller juvenile to A­3, because of the apparently more juvenile features of a smaller carapace, 3 (not 6) setae on the dorsal margin of article 3 of the first antenna, and only 10 setae on the seventh limb.

The description of an instar of C. variabilis assigned to A­2 ( Kornicker, 1991) includes a seventh limb with only 8 setae (the first antenna is missing). As C. marranyin has an A­3 stage with 10 setae on the seventh limb, we believe this instar of C. variabilis to be more appropriately assigned to the A­4 stage.

No other male instars for the genus have been described. The male instar here is assigned to the A­1 stage, because of the presence of the robust endopod on the second antenna.

Cylindroleberis is known from the northwest African coast, the Mediterranean, Red Sea, southeast African coast, and the Indo –Pacific region around Thailand and the Philippines, over to the Marshall Islands. The new species appears to be most similar to species from the Indo –Pacific, and its identification extends the southern distribution of the genus.

Etymology.—“ Marranyin ” is an Australian aboriginal word from the Wagiman language of northern Australia, meaning “sand,” in reference to the type locality for this species, Sandy Point.

Figures

FIGURE 5. Cylindroleberis marranyin, new species, adult female holotype NMV J 53214, A, carapace; B, first antenna, left, l. v., sixth article medial seta not shown (92 X); C, second antenna, left, l. v., exopod broken, represented by dotted line, setae on exopod articles 3 – 9 not shown (79 X); D, coxale endite of left mandible, m. v. (115 X); E, mandible, left, m. v., basale ventral terminal setae not shown (represented by circles), medial seta on endopod article 2 and terminal setae on article 3 not shown (except for terminal claw) (130 X); F, maxilla, left, l. v. (126 X); G, fifth limb comb (114 X); H, sixth limb, right, m. v. (65 X); I, seventh limb (77 X); J, furca, left lamella (108 X); K, lateral eye (119 X). Female A­ 2 instar, paratype NMV J 53216, L, carapace; M, first antenna, right, l. v (111 X).

FIGURE 6. Cylindroleberis marranyin, new species, adult male paratype NMV J 53215, A, carapace; B, first antenna (part) right, l. v., s­seta filaments not shown, b­seta broken, c­ and f­setae filaments not shown (90 X); C, first antenna, article 5, proximal node, m. v. (120 X); D, second antenna endopod (94 X); E, fifth limb comb (200 X). Male A­ 1 instar, paratype, NMV J 53221, F, carapace;