Atyaephyra acheronensis, Christodoulou, Magdalini, Antoniou, Aglaia, Antonios Magoulas, & Athanasios Koukouras,, 2012

Christodoulou, Magdalini, Antoniou, Aglaia, Antonios Magoulas, & Athanasios Koukouras,, 2012, Revision of the freshwater genus Atyaephyra (Crustacea, Decapoda, Atyidae) based on morphological and molecular data, ZooKeys 229, pp. 53-110 : 75-76

Atyaephyra acheronensis sp. n. Figs 11-12

Atyaephyra sp. n. 2. - Christodoulou et al. 2008: Fig. 4A.

Atyaephyra sp. n. 2. - Christodoulou et al. 2010: Fig. 2, partim.

Atyaephyra desmarestii . - Franjević et al. 2010: 159-166.

Material examined.

Type material. Holotype: NHM 2012.1493, 1 ovig. ♀ (CL 5.9 mm), Greece, Epirus, Acherontas River, 39°13.96'N, 20°29.11'E (Fig. 1, stn 71), among aquatic plants, 15.4.2012, coll. Ch. Anastasiadou (Sequenced specimen: Ach1).

Non-type material.

Greece: 1 ♀ (CL 7.6 mm) (Sequenced specimen: Lour1) and 1 ovig. ♀ (CL 7.0 mm) (Sequenced specimen: Lour2), Greece, Epirus, Louros River, 39°03.14'N, 20°46.26'E (Fig. 1, stn 72), 15.4.2012, coll. Ch. Anastasiadou; Slovenia: 1 ♂ (CL 5.1 mm), Dragonja River (Fig. 1, stn 66), Aug.1971 (Sequenced specimen: Drag1).

Description.

Rostrum long, dorsal margin straight, 6.28-6.66 × as long as high, equal to or longer than scaphocerite. 19-26 pre orbital teeth on dorsal margin of rostrum arranged up to tip. With 1-3 post orbital teeth and 3-8 teeth on ventral margin of rostrum (Fig. 11A). Carapace smooth with pterygostomial angle not protruding, rounded (Fig. 11B). Pleuron of fifth abdominal segment pointed with an acute posterior angle (Fig. 11C). Telsonwith four pairs of dorsal spines arranged in curved fashion (Fig. 11D). Distal border of telson with 12-15 spines (6-8 pairs) arranged in a fan-like pattern. Outermost pair of spines shortest, similar to dorsal spines, adjacent pair stronger terminating before the finely setulose, inner pairs (Figs 11 D–E). Antennulary stylocerite with its tip failing to reach or reaching distal margin of basal peduncle segment. Anterolateral lobe of basal segment short and round (Fig. 11G). Distal segment of antennular peduncle with 1-2 spines (Fig. 11F). Basal lower endite of maxilla densely covered with long simple setae arranged in 18-20 oblique parallel rows. Endite of maxilla 1.56-1.65 × as long as basal lower endite (Fig. 12G). Basal endite of first maxilliped reaching clearly beyond distal end of exopod (Fig. 12F). Distal one-third of terminal segment of third maxilliped bearing 1-5 mesial spines and one subdistal lateral spine near the base of larger terminal spine, interpretable as dactylus (Fig. 12H). Armature along flexor margin of dactylus of third and fourth pereiopod consisting of 5-7 and 6-7 spines respectively (Figs 12B, 12D). Merus of third and fourth pereiopod with 4-6 and 3-4 spines respectively (Figs 12A, 12C). Armature along flexor margin of dactylus of fifth pereiopod consisting of 27-38 spines (Fig. 12E). Endopod of first male pleopod expanded proximally and with a distal portion elongated (ribbon shaped) and tapering. Endopod with 18 spines arranged on a slightly curved inner margin and 12 setae arranged on outer margin (Fig. 12I). 579-1117 eggs of 0.40-0.55 × 0.25-0.35 mm in size.

Size.

Atyaephyra acheronensis sp. n. is a large sized species with maximum carapace length to be 5.1 mm in ♂♂, 7.6 mm in ♀♀ and 7.0 mm in ovig. ♀♀.

Molecular characters.

Molecular information based on the COI sequences provides compelling evidence that is a well defined species. Atyaephyra acheronensis sp. n. is unique in Atyaephyra in having 2 haplotypes not shared by any other species. Furthermore, it differs from all its congeners in the following nucleotide positions in the COI gene of Atyaephyra desmarestii specimen Dour1, position 255: adenine (A) and position 318: cytosine (C). Finally, the mean genetic distances between Atyaephyra acheronensis and the remaining Atyaephyra species range from 8.3% to 23.8% (Table 2).

Etymology.

Atyaephyra acheronensis sp. n.is named after the Acheron (Acherontas) River, Greece, the type locality.

Distribution.

Atyaephyra acheronensis sp. n. is found in freshwater habitats of Croatia (Krka River), Slovenia (Dragonja River) and Greece (Acherontas River and Louros River) (see material examined and Fig. 1). Although this study was based on a limite d number of specimens, it is postulated that Atyaephyra acheronensis sp. n. occurs in more rivers covering an area ranging from Croatia to Greece.

Remarks.

In addition to the type- and non type-material we investigated the morphology of the following specimens originating from the Balkan Peninsula: 6 ♀♀ collected from Dragonja River (Fig. 1, stn 66), Slovenia; 3 ♀♀ collected from Jadro River (Fig. 1, stn 67), NHMW 460 and 4 ♀♀ (3 ovig.) and 1 ♂ from Ombla River (Fig. 1, stn 69), NHMW 459, Croatia; 2 ♂♂ collected from Krupa River (Fig. 1, stn 68), NHMW 458, Bosnia and Herzegovina; 9 ♀♀ and 12 ♂♂ from Aoos River (Fig. 1, stn 70), Albania; 47 ♀♀ (13 ovig.) and 9 ♂♂ from Acherontas River (Fig. 1, stn 71), Greece, 10 ♀♀ and 2 ♂♂ collected from Louros River (Fig. 1, stn 72), Greece, 2 ♀♀ from Pamisos River (Fig. 1, stn 73), Greece, 4 ♀♀ and 1 ♂ sampled from Evrotas River (Fig. 1, stn 74), NHM 1987.93, Greece. However, without sequencing the individuals, their placement to Atyaephyra acheronensis sp. n. can’t be made with certainty.

Out of the 135 characters examined (see Appendix: Table 1) there were no morphological features distinguishing Atyaephyra acheronensis sp. n. from Atyaephyra desmarestii and Atyaephyra tuerkayi sp. n. Nevertheless, Atyaephyra acheronensis sp. n. presents a more limited variability in the values of its morphological characters than Atyaephyra desmarestii . Atyaephyra acheronensis sp. n. can easily be distinguished from Atyaephyra orientalis , Atyaephyra stankoi and Atyaephyra thyamisensis by the presence of fewer mesial spines (1-5) on terminal segment of third maxilliped (Fig. 12H) (vs. 10-38 in Atyaephyra orientalis , Atyaephyra stankoi and Atyaephyra thyamisensis ; Figs 4H, 6H, 8H) and by the basal endite of first maxilliped overeaching distal end of exopod (Fig. 12F) (vs. failing to reach or reaching distal end in Atyaephyra orientalis , Atyaephyra stankoi and Atyaephyra thyamisensis ; Figs 4F, 6F, 8F). Atyaephyra acheronensis sp. n. can be separated from Atyaephyra strymonensis by the presence of 1-3 post orbital rostral teeth (Fig. 11A) (vs. no post orbital teeth present leaving short unarmed proximal gap in Atyaephyra strymonensis ; Fig. 9A) and by the endite of maxilla being 1.56-1.65 × as long as basal lower endite (Fig. 12G) (vs. 1.77-1.95 in Atyaephyra strymonensis ; Fig. 10G).