A revision of the genus Arenopontia Kunz, 1937 (Copepoda, Harpacticoida, Arenopontiidae), including the description of five new species Author Sak, Serdar Department of Biology, Faculty of Science and Literature, Balıkesir University, Balıkesir, Türkiye. Author Karaytuğ, Süphan Department of Biology, Faculty of Science, Mersin University, Mersin, Türkiye. Author Huys, Rony Department of Life Sciences, Natural History Museum, Cromwell Road, London SW 7 5 BD, UK. text Zootaxa 2024 2024-04-04 5433 1 1 50 http://dx.doi.org/10.11646/zootaxa.5433.1.1 journal article 10.11646/zootaxa.5433.1.1 1175-5326 10953646 06E5A735-A276-41D7-A9EE-B09642D953B6 Arenopontia nesaie Cottarelli, 1975 Arenopontia ( Arenopontia ) nesaie Cottarelli, 1975 : Bodin (1979: 124) Arenopontia nesiae Cottarelli, 1975 : Martínez Arbizu & Moura (1994: 57) , Wells (2007: 55 , 192) [ lapsus calami ] Arenopontia nessiae Cottarelli, 1975 : Martínez Arbizu & Moura (1994: 63) [ lapsus calami ] Arenopontia ciplaki : nomen nudum in Sak (2004: 117) Original description. Cottarelli (1975) : 65–70; Figs 1–11 , 13–16 , 18–19 , 21–23. Additional description. Sak et al. (2008: 414–420 ; Figs 1–5 ). Type locality. Italy , Sardinia , near Cagliari, Bay of Quartu S. Elena, Poetto beach . Remarks. Wells (2007) pointed out that many of the arguments used by Cottarelli (1975) to distinguish A. nesiae from A. subterranea were based on a comparison with very inadequately described aspects of A. subterranea . Both sexes of this species were recently redescribed in detail by Sak et al. (2008) , based on material from Dutlimanı beach (Sea of Marmara, Türkiye ). They noted minute differences with Cottarelli’s (1975) type material from Sardinia , Italy , and considered Mitwally & Montagna’s (2001) Egyptian population, identified as A. nesaie , a taxon of doubtful identity (see below). The species is widespread in the Mediterranean from the Spanish east coast to at least Crete and the Turkish west coast ( Cottarelli 1975 ; Martínez Arbizu & Moura 1994 ; Bruno et al. 1998 ; Sak 2004 ; Lampadariou et al. 2005 ; Sevastou 2005 ; Sak et al. 2008 ; Sevastou et al. 2011 ; Alper et al. 2015 ; Metin et al. 2022 ). Arenopontia nesaie is most closely related to A. gunduzi sp. nov. (known only from the Pas-de-Calais region, France ) with which it shares the dorsal spur on the caudal ramus and the armature formula of P2–P6. It differs from this species in the longer P1 endopod, the shorter P4 enp-1 (being distinctly shorter than P4 exp-1 instead of equally long), the innermost element on the fifth legs of both sexes being longer and more slender, and the relatively longer posterior spinous process on the caudal ramus. Arenopontia subterranea lacks the dorsal spur on the caudal ramus and has a distinctly shorter P1 endopod (enp-1:exp = 1.5 vs 2.0 in A. nesaie and 1.7 in A. gunduzi sp. nov. ). It is conceivable that Bonne’s (2003) record of A. nesaie from the Kwinte Bank off the Belgian coast refers to A. gunduzi sp. nov.