Arenopontia, KUNZ, 1937

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 : 412-413

GENUS ARENOPONTIA KUNZ, 1937

The genus Arenopontia currently contains 32 species allocated to three subgenera ( Bodin, 1997; Karanovic, 2000) (or 30 species when the subgenus Pararenopontia is attributed full generic rank; see Wells, 2007). The subgenus Arenopontia encompasses 13 species and possibly one subspecies [ Apostolov (1973) claimed that Arenopontia pontica Apostolov, 1969 is a subspecies of A. subterranea ], whereas Karanovic (2000) listed 17 valid species in the subgenus Neoleptastacus [note that Arenopontia sakagamii Itô, 1978 was also listed by this author, but according to Wells & Rao (1987) this species is synonymous with Arenopontia indica Rao, 1967 ]. The subgeneric division first proposed by Wells (1967) fell into disuse in the 1980s, when Mielke (1982a, b, 1985, 1987) described several new species from Central and South America without attributing them to either subgenus. Unfortunately, Bodin (1988, 1997) erroneously listed three of those species, Arenopontia clasingi , Arenopontia pacifica , and Arenopontia spicata (all described by Mielke, 1985), under the nominate subgenus Arenopontia (Arenopontia) , as if Mielke (1985) had originally intended such a subgeneric assignment. It is obvious from Mielke’s (1985, 1987) descriptions, however, that these species share the Neoleptastacus type of P5, and should be assigned to this subgenus if Wells’ (1967) subdivision bears any phylogenetic significance. Bodin’s (1988, 1997) error unfortunately perpetuated in the literature, as exemplified by Karanovic’s (2000) recent key to the subgenus Neoleptastacus , which makes no reference to Mielke’s (1985) species. Arenopontia clasingi , A. pacifica , and A. spicata are here formally transferred to Neoleptastacus , which will be attributed full generic rank (see below).

The subgenus Arenopontia currently encompasses the following species: A. subterranea ; Arenopontia arenarida ( Pennak, 1942a) ; Arenopontia stygia Noodt, 1955b ; Arenopontia orientalis ( Krishnaswamy, 1957) ; Arenopontia intermedia Rouch, 1962 ; Arenopontia dillonbeachia Lang, 1965 ; Arenopontia problematica Masry, 1970 ; Arenopontia nesaie Cottarelli, 1975 ; Arenopontia riedli Lindgren, 1976 ; and Arenopontia peteraxi Mielke, 1982a . Bodin (1979, 1988, 1997) added A. subterranea Kunz ? sensu Şerban & Eitel- Lang (1957) as a species incertae sedis, but the latter should be regarded as a nomen nudum. Various Eastern European authors (e.g. Georgescu, Marcus & Şerban, 1962) have repeatedly referred to Şerban & Eitel-Lang’s (1957) paper as ‘Notes sur les Copépodes de la Mer Noire. Izdanija, Skopje’; however consistently, no proper citation of volume number or pagination has been given. According to Şerban (1959), the authors were at that time still in the process of submitting the paper (‘Une description detaillée en sera publiée par Şerban & Eitel-Lang’), and it has now been confirmed (C. Pleşa, pers. comm. to RH, 1 August 1996) that the manuscript was never published. The reference nevertheless mistakenly persisted in modern literature (e.g. Apostolov & Marinov, 1988).

Morphological comparison revealed a core group of closely related species within the (sub)genus Arenopontia , encompassing the type species A. subterranea , A. pontica , A. problematica , A. nesaie , and A. riedli . These five species differ from other members of the family in their unique P1 morphology, including: (1) the prehensile endopod with enp-1 being distinctly elongate, and with enp-2 bearing an outer spine and an inner geniculate claw, and (2) the modification of the inner distal element of exp-3 into a penicillate seta. Based on these autapomorphies, we here restrict the generic concept of Arenopontia to this subterranea group. Our unpublished studies based on sandy beach samples from all over Europe revealed that many new species await description (e.g. Sak, Karaytuǧ & Huys, in press a), and that the five currently known species only represent the tip of the iceberg. The genus is primarily restricted to the Northern Hemisphere, the only exception being Wells’ (1967) doubtful outlier of A. subterranea in Mozambique.

Diagnosis: Arenopontiidae . Urosomites without conspicuous surface ornamentation. Anal somite without paired dorsolateral spinous processes. Anal operculum not modified. Hyaline frills of abdominal somites with rectangular digitate lappets. Caudal ramus with dorsolateral spur or raised spinular row near medial margin. P1 exopod: three-segmented; exp-1 with outer spine; exp-3 with two spines, one outer distal geniculate seta, and one inner distal penicillate seta. P1 endopod: prehensile, longer than exopod; enp-2 with one outer distal spine and one inner distal geniculate claw. P2–P3 endopods: two-segmented. P3 enp-2 with outer distal element defined at base or absent. P4 enp-2 with well developed outer distal element. Armature formula as follows:

Exopod Endopod

P2 0.0.021 0.110 or 0.120 P3 0.0.021 0.010 or 0.020 P4 0.0.021 0.020

P3 endopod male: not sexually dimorphic, twosegmented. P5 with outer basal seta and three or four discrete elements: innermost one distinctly smaller in males. P 6 male with one or two seta(e).

Type species: Arenopontia subterranea Kunz, 1937 (by monotypy).

Other species: Arenopontia problematica Masry, 1970 ; Arenopontia nesaie Cottarelli, 1973 ; Arenopontia riedli Lindgren, 1976 .

Species inquirendae: Arenopontia pontica Apostolov, 1969 ; Arenopontia nesaie Cottarelli, 1975 sensu Mitwally & Montagna (2001) .

Nomen nudum: Arenopontia subterranea Kunz, 1937 ? sensu Şerban & Eitel-Lang (1957).