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) Sak, Serdar Huys, Rony Karaytuğ, Süphan Zoological Journal of the Linnean Society 2008 152 409 458 KUNZ, 1937 Kunz 1937 [362,669,1230,1252] Hexanauplia Arenopontiidae Arenopontia Animalia Harpacticoida 3 412 Arthropoda genus  The subgenus  Arenopontiacurrently 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. subterraneaKunz? sensuŞerban & 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 typespecies  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  Arenopontiato this  subterraneagroup. Our unpublished studies based on sandy beach samples from all over Europe revealed that many new species await description (e.g. Sak, Karaytuǧ & Huys, in press a), and that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. subterraneain 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 malewith one or two seta(e).   Typespecies:  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? sensuŞerban & Eitel-Lang (1957).