Apricaphanius, Freyhof & Yoğurtçuoğlu, 2020

Freyhof, Jörg & Yoğurtçuoğlu, Baran, 2020, A proposal for a new generic structure of the killifish family Aphaniidae, with the description of Aphaniops teimorii (Teleostei: Cyprinodontiformes), Zootaxa 4810 (3), pp. 421-451 : 441-442

Apricaphanius , new genus

Fig. 15

Type species. Lebias iberus Valenciennes in Cuvier & Valenciennes, 1846 .

Diagnosis. Apricaphanius is superficially similar to Anatolichthys , from which it is distinguished by having a narrow, black dorsal-fin margin (vs. wide black margin in Anatolichthys ) followed by a narrow or wide white or hyaline sub-marginal band in nuptial males. Nuptial male Anatolichthys never have a white sub-marginal band in the dorsal fin. In the male Anatolichthys the dorsal fin is completely black or it has a wide greyish or black margin, followed by a white proximal band ( A. iconii ) or by a proximal row of white spots or blotches distinctly or slightly above the dorsal-fin base, or by a hyaline field with single or rows of brown spots. Furthermore, male Apricaphanius are diagnosed by the absence of flank bars (in A. saourensis ) or possession of 14–22 irregular, usually vertically split, flank bars, overlaid with numerous minute whitish spots in the adult male (vs. 5–13 regular flank bars, except A. villwockii , and not overlaid by spots in all species except A. irregularis ). Apricaphanius is distinguished from the remaining genera in the family Aphaniidae by the following combination of non-unique characters: head canals absent (vs. present in Aphanius and Aphaniops ); dermal sheath at the anal-fin base in the nuptial female present (vs. absent in Aphaniops ); possession of a single row of tricuspid teeth (vs. three rows of conical teeth in Kosswigichthys ); body covered by scales (vs. naked in Kosswigichthys ); pelvic fin present (vs. absent in Tellia ); black or dark-brown bars in the caudal fin of the male present, rarely absent in A. saourensis (vs. absent in Paraphanius); flank pattern in the male comprising a series of black or brown bars or intricate silvery vermiculation (vs. small whitish or blue sports arranged in vertical series or very narrow bars in Paraphanius); a bold, black spot at the centre of the caudal-fin base in the female present (vs. absent in Paraphanius); dorsal- and anal-fin margins in the male black (vs. without black margins in Aphaniops , yellow in Tellia , only dorsal-fin margin black in Aphanius ); background colour of caudal fin identical to interspaces between flank bars (vs. caudal fin pale or deep yellow or orange, distinct from silvery interspaces between flank bars in Aphanius ).

Included species. Apricaphanius iberus , A. baeticus , A. saourensis .

Distribution. Apricaphanius species are distributed along the coastline of the Iberian Peninsula from the southern Atlantic slope of Spain (lower Guadalquivir region) to Catalonia, plus the Oued Saoura basin in northwestern Algeria ( Blanco et al. 2006; Doadrio et al. 2002, Gonzales et al. 2014) ( Fig. 14 ). Other records from Algeria represented in Figure 14 are based on historic records of fishes identified as A. iberus by Pellegrin (1921) and may have been populations of A. saourensis , but none have been confirmed since.

Etymology. Based on the Latin substantive Apricus, shining, for the many small white spots on the flanks of the male, which give them a shiny appearance. Gender masculine.

Remarks. The molecular phylogeny presented by Hrbek et al. (2002) placed Apricaphanius as sister genus to all Aphaniids, except Aphaniops, Paraphanius and Tellia . The molecular tree published by Esmaeili et al. (2020) placed Apricaphanius close to Esmaeilius , while Geiger et al. (2014), placed Apricaphanius as sister to Aphanius and Anatolichthys in their analysis of Mediterranean species ( Fig. 1 ). The results of these studies clearly demon- strate that Apricaphanius cannot be placed in Anatolichthys , and that it represents a distinct, well-distinguished phylogenetic group. To avoid paraphyly, Apricaphanius must be treated as a distinct genus despite its superficial similarity to Anatolichthys .

Apricaphanius and Anatolichthys species lack head canals and possess pelvic fins, a dermal sheath at the analfin base in the nuptial female, and a single row of tricuspid teeth.

Male Apricaphanius and Anatolichthys possess a black dorsal-fin margin, which is narrow in Apricaphanius (vs. wide, often the entire dorsal fin is black in Anatolichthys ). Male Apricaphanius are well distinguished from all Anatolichthys by presence of a white or hyaline sub-marginal band in the dorsal fin often with some isolated brown spots or blotches (vs. absence in Anatolichthys ). Male Apricaphanius either lack flank bars ( A. saourensis ) or possess 12–22 narrow, irregular set and shaped flank bars which are usually split vertically and overlaid with numerous minute whitish spots in adults (vs. 5–13 regularly set and shaped bars, not overlaid by spots in all but one Anatolichthys species). Male Anatolichthys villwocki possess 13–25 narrow brown flank bars, but also 4–14 vertical rows of small black or brown spots in the caudal fin (vs. 1–4 bold black bars in Apricaphanius species).

The flank bars are not very easy to see in male Apricaphanius , since the flank bars and dorsal-fin colour pattern often dissociate in adult individuals larger than 25 mm SL. The flank pattern in the adult male Anatolichthys irregularis also comprises numerous small white spots ( Yoğurtçuoğlu & Freyhof 2018) and this is also the case in some species of Paraphanius such as P. alexandri and P. mentoides . We suspect the presence of small white spots on the flank has evolved at least four times in Aphaniidae , and its occurrence in Apricaphanius , Anatolichthys irregularis, Paraphanius and Tellia is the result of convergent evolution.

Figures

FIGURE 1. Two-way demonstration of basic cladograms of Aphaniid genera against their character states. Cladograms were simplified and drawn by adapting phylogenetic trees provided by previous studies. Black bars represent presence and white bars represent absence of the corresponding character state. Small dots within the bars stand for the presence of exceptional species to the general state.

FIGURE 14. Records of Apricaphanius and Tellia species.

FIGURE 15. Left column from the top, females: A. baeticus, FSJF 4102, 33 mm SL; Spain: Arroyo Salado; A. iberus, not preserved, 25 mm SL; Spain: Ebro delta; A. saourensis, FSJF 3635, 32 mm SL; Algeria: Mazzer. Right column from the top, males: Apricaphanius baeticus, FSJF 4015, 28 mm SL; Spain:Arroyo del Moscardo; A. iberus, not preserved, 35 mm SL; Spain: Ebro delta; A. saourensis, not preserved, 27 mm SL; Algeria: Mazzer;