Psammoleptastacus barani, Sak & Huys & Karaytuğ, 2008

Sak, Serdar, Huys, Rony & Karaytuğ, Süphan, 2008, Disentangling the subgeneric division of Arenopontia Kunz, 1937: resurrection of Psammoleptastacus Pennak, 1942, re-examination of Neoleptastacus spinicaudatus Nicholls, 1945, and proposal of two new genera and a new generic classification (Copepoda, Harpacticoida, Arenopontiidae), Zoological Journal of the Linnean Society 152, pp. 409-458 : 426-433

PSAMMOLEPTASTACUS BARANI SP. NOV.

Arenopontia stygia Noodt, 1955b sensu Marinov (1971)

Type locality: Turkey, Black Sea coast, Istanbul, Sahilköy (east of Bosporus ); sandy beach .

Material examined: Holotype ♀ (dissected on eight slides) ( BUZM) . Paratypes are one ♀ and one ♂ in alcohol ( NHM reg. nos. 2006. 1966–1967), and two ♂♂ dissected on two and seven slides, respectively ( NHM reg. nos. 2006. 1968–1969); all collected at type locality; leg. S. Karaytuğ and S. Sak, 01 May 2001 .

Description

Female: Total body length from tip of rostrum to posterior margin of caudal rami: 330–380 M m (mean = 361 M m; N = 7). Maximum width measured at P5-bearing somite. Body: slender and cylindrical, without clear distinction between prosome and urosome ( Fig. 8A, B). Hyaline frills of thoracic somites weakly developed and crenulated; those of genital double-somite and free abdominal somites strongly developed, and consisting of rectangular digitate lappets ( Figs 8A, B, 9A, 8D). Genital double-somite ( Fig. 9A): slightly longer than wide; without chitinous ribs marking original segmentation; with one middorsal, two lateral, and two ventral pores. Anal somite ( Fig. 8C, D): with two dorsal and two lateral pores. Anal operculum: with minute spinules along free distal margin ( Fig. 8C). Anus: positioned subterminally between caudal rami.

Caudal rami ( Fig. 8C, D): approximately 2.75 longer than basal width, tapering posteriorly; with one pore dorsally, one near ventral proximal margin ( Fig. 9A), and one laterally near outer spinules; outer distal corner produced into posteriorly directed recurved spinous process, accompanied by ventral spinular row at base; dorsomedial surface with posteriorly directed spinous process arising from base of seta VII. Armature: as in P. arenaridus , but with a more foliaceous seta VII.

Rostrum ( Figs 8A, 10A): broadly subtriangular, tapering apically, with two delicate sensillae and one subapical ventral pore.

Antennule ( Fig. 10A, B): six-segmented. Segment 1: with one seta near anterodistal margin. Segment 2: longest, about 3.5 times longer than wide. Segment 4: with long aesthetasc (30- M m long) fused at base with seta. Distal segment: with seven naked setae (one of which spatulate), and apical acrothek consisting of short aesthetasc (13- M m long) and two slender setae. Armature formula: 1-[1], 2-[7 + 1 plumose], 3-[4], 4-[(1 + ae)], 5-[1], 6-[7 + acrothek].

Antenna ( Fig. 10C, D): coxa small, without ornamentation. Original segmentation of allobasis marked by partial transverse surface suture; with one spinular row along exopodal margin. Exopod: onesegmented, elongate, with long naked seta apically. Free endopod: with two spinular rows on anterior surface and finer spinules at outer distal corner; lateral armature consisting of two short spines; apical armature consisting of two spines and three geniculate setae, the longest of which with spinules around geniculation and fused basally to tiny accessory seta.

Mandible, maxillule, maxilla, and maxilliped: as in A. nesaie .

P1 ( Fig. 11A): intercoxal sclerite long and rectangular. Praecoxa: subtriangular and naked. Coxa: without ornamentation. Basis: with spinular row near bases of endopod and exopod; anterior surface with a proximal pore and a small inner basal seta. Exopod: three-segmented; about 1.2 times longer than endopod; all segments with spinules along outer margin; exp-1 longest, with long unipinnate outer spine; exp-2 without outer element; exp-3 with two unipinnate outer spines and two geniculate apical setae. Endopod: two-segmented, not prehensile; enp-1 distinctly longer than exp-1, with a serrate seta at about two-thirds of the length of the inner margin, and several spinules along outer margin; enp-2 less than half the length of enp-1, with two geniculate setae (inner one about twice as long as outer).

P2–P4 ( Fig. 11B–D): intercoxal sclerites naked. Praecoxae: small and naked. Coxae: rectangular and without ornamentation. Bases: smaller than coxae, with a spinular row near base of endopod (P3–P4); anterior surface with a proximal pore; outer basal seta absent (P2), plumose (P3), or naked (P4). Exopods: three-segmented; segments with spinular ornamentation, as illustrated; inner distal seta of exp-3 sparsely bipinnate, all other elements unipinnate; P3–P4 exp-3 with anterior pore. Endopods: two-segmented, with few spinules, as illustrated. P2 enp-2: with a long, apically serrate, backwardly directed seta. Distal margin of P3 enp-2: with naked outer spine and long bipinnate inner seta. P4 enp-1: slightly shorter than exp-1; distal margin of enp-2 with long, basally fused, serrate seta, and long, unipinnate outer seta. P2–P4: spine and seta formula as for the genus.

Fifth legs ( Fig. 9A): closely set together but not touching in ventral midline. Baseoendopod and exopod fused, forming a semicircular plate; distal margin with two short bipinnate spines flanked by two long bipinnate setae; outer basal seta long and sparsely plumose.

Genital field ( Fig. 10E): with genital apertures fused forming median common slit; closed off by fused P6 forming operculum, with one minute spinous process on either side; copulatory pore located midventrally, close to genital slit; seminal receptacles difficult to discern.

Male: Total body length from tip of rostrum to posterior margin of caudal rami: 290–335 M m (mean = 315 M m; N = 6). Body ornamentation ( Figs 9B, 12A): essentially as in female. Sexual dimorphism: in antennule, genital segmentation, P3 endopod, P5, and P6. Spermatophore length: approximately 45 M m.

Antennule ( Fig. 12C, D): nine-segmented, haplocer; geniculation between segments 7 and 8. Segment 2 longest, about 2.2 times as long as wide; segment 4 an incomplete sclerite with one modified (fused at base) and one tiny element; segment 5 with long aesthetasc (45- M m long) fused basally to very small seta; segments 6–8 with one seta and one basally fused spiniform element. Segment 9: with one spatulate seta. Setal formula: 1-[1], 2-[7 + 1 plumose], 3-[4 + 1 pinnate spine], 4-[1 + 1 modified], 5-[2 + (1 + ae)], 6-[1 + 1 modified], 7-[1 + 1 modified], 8-[1 + 1 modified], 9-[7 + acrothek]. Acrothek consisting of short aesthetasc (13- M m long) fused basally to two slender setae.

P3 endopod ( Fig. 12B): two-segmented; enp-1 with few strong spinules along outer margin; enp-2 *Length of rami calculated as sum of segment lengths.

minute, with strong spinule at outer distal corner, short fine seta arising from inner distal corner (homologous with long inner distal seta of female), and naked curved apical spine, discrete at base (homologous with outer distal spine of female).

P5 ( Fig. 9B): with armature as in female, but with innermost element of distal margin much shorter and bare.

Sixth legs ( Fig. 9B): asymmetrical, with smallest P6 closing off functional gonopore; each with two pinnate setae.

Etymology: The species is named after Prof. İbrahim Baran, Dokuz Eylül University, in recognition of his contributions to herpetology in Turkey.

Remarks: Psammoleptastacus barani sp. nov. differs from its two known congeners in the longer P1 endopod, and the length of P4 enp-2, which is shorter than, or at most as long as, the proximal exopod segment, instead of being distinctly longer. It is similar to P. arenaridus in the length of the caudal ramus, but deviates from it in the detailed morphology of the male P3 endopod. Marinov (1971) recorded a few specimens from the beaches of the Arkutino region (south of Sozopol) along the Bulgarian coast, which he attributed to A. stygia . He noted the difference in the relative length of the P1 endopod between his specimens and Noodt’s (1955b) type population of P. stygius . The similarity in the relative length of the P1 endopod, P4 endopod, and caudal ramus, the P3 endopodal sexual dimorphism, and the female P5, leave little doubt that Marinov (1971) was dealing with P. barani sp. nov. The only discrepancy between both descriptions is found in the male P5, which has a much longer innermost seta in the Bulgarian material. Apostolov (1973) claimed that considerable variability was found in the P5 of his Black Sea A. subterranea (no localities specified), but it is conceivable that his drawings of the female P5 were based on two different species: his Figure 18-5 shows a P5 of the Arenopontia type, whereas his Figure 18-6 was almost certainly based on the species previously identified by Marinov (1971) as A. stygia . Note that the type locality of P. barani sp. nov. is in close proximity to the Bulgarian collecting sites.