Arenopontia pontica, APOSTOLOV, 1969

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 : 421-422

ARENOPONTIA PONTICA APOSTOLOV, 1969

Original description: Apostolov (1969): pp. 125–127; Abb. 36–45.

Type locality: Bulgaria, south of Lozenetz , Düni Beach ; 5 m from low-tide mark.

Remarks: Apostolov’s (1969) description of A. pontica , from the Bulgarian Black Sea coast, is a taxonomic nightmare because of several internal inconsistencies between the text and illustrations. Apostolov (1969: 111) claimed to have found two females (although on p. 125 he stated that three females were recorded), but for some inexplicable reason provided a brief diagnosis of the male. He referred to Figure 46 in his description of the male P5, but this figure is not printed. His illustrations of the female show several extraordinary features not found in any other member of the Arenopontiidae : (1) the antennary exopod is bisetose – in all species of Arenopontia this ramus displays only one apical seta; (2) P1 exp-2 bears an outer spine – the absence of this spine is a high-level diagnostic, being a synapomorphy linking the Parastenocarididae , Leptopontiidae , and Arenopontiidae ( Martínez Arbizu & Moura, 1994) ; (3) P1 enp-1 lacks an inner seta – this seta is present in all species, except for the inadequately described A. problematica and Arenopontia accraensis Lang, 1965 – we have been able to confirm its presence in the types of A. problematica ; (4) P2–P3 exp-3 with four elements, i.e. with two outer spines and two terminal setae – all Arenopontiidae have only one outer spine and share a [021] setal formula on the distal exopod segment – note that Apostolov (1969) contradicts himself in the setal formula table on p. 125 (three elements), his Figure 42 (four elements), and the comparative table on p. 127 (four elements); (5) P2–P3 exp-2 bears a long inner seta – the latter seta is absent in all other arenopontiids, except for Arenopontia angolensis Kunz, 1971 , which according to Kunz’ (1971) setal formula possesses a seta on P2 exp-2. However, as Kunz neither illustrated the P2 nor mentioned this character in the text or the table comparing Arenopontia africana f. africana and A. africana f. angolensis (he does state that the P2 is as in the nominate subspecies, apart from the ornamentation of the inner seta on enp-2), we strongly suspect that his report is based on a slip of the pen in his table, rather than on an observational error.

Apostolov (1969) recognized a close relationship with A. subterranea , A. indica and A. sp. sensu Griga (1964) [the latter was later identified as conspecific with Stenocaropsis valkanovi (Marinov, 1974) , family Cylindropsyllidae ]. In our opinion it is impossible to make any positive statement on the identity and *According to Kunz (1937) and Masry (1970) the P6 is a minute plate bearing three elements, but it is likely that these claims are based on observational errors.

†Based on Sak’s (2004) redescription.

‡ Masry (1970) claimed there are two distal elements on P2–P3 enp-2 but this has been corrected by Sak (2004). CR = caudal ramus; An Op = anal operculum.

possible relationships of A. pontica other than that this species can be assigned to the genus Arenopontia as diagnosed herein. Pending redescription, A. pontica is considered here as species inquirenda. This course of action is in contrast to Marinov’s (1971) suggestion to relegate A. pontica to a junior subjective synonym of A. subterranea . Marinov rightly pointed out some of the weaknesses in Apostolov’s (1969) description, but it remains a mystery how he reconciled the many differences between the latter and his own illustrations of A. subterranea from the Bulgarian coast.

Inspired by the variability reported for French mediterranean ( Chappuis, 1954a) and Romanian populations ( Şerban, 1959) of A. subterranea , but apparently unaware of Marinov’s (1971) paper, Apostolov (1973) claimed that A. pontica may well be a synonym of the latter. He further proposed that the Black Sea specimens represent a new subspecies of A. subterranea , but refrained from formally naming it. Apostolov stated that considerable variability was found in the caudal rami, the P1 exopod, and the P5, but it is conceivable that this is at least partly attributable to his failure to discriminate between two or more coexisting species. His drawings of the female P5 clearly refer to two different species: his Figure 5 shows a fifth leg of the subterranea type, whereas Figure 6 was almost certainly based on the species previously identified by Marinov (1971) as A. stygia (and described below as Psammoleptastacus barani sp. nov.). In accordance with Şerban’s (1959) observations, Apostolov (1973) maintained that his material did not display the foliaceous seta VII, or the penicillate seta on P1 exp-3.

Key to species: A simple dichotomous identification key is difficult to construct; however, species can be reliably identified by considering the salient diagnostic characters summarized in Table 3.