Atyaephyra rosiana de Brito Capello, 1867: 6–7, Pl. 1, Figs 1A–E [type locality: Coimbra, Portugal]; by monotypy.

Carapace with supraorbital and antennal tooth. Rostrum long and armed up to the tip. Eyes well developed, pigmented. Exopods present only on the two first pairs of pereiopods, carpus of first and second pair of pereiopods with a distal excavation. Uropod diaeresis with a single spine (rarely two). Appendix masculina of male second pleopod long, sub-cylindrical and armed with numerous spiniform setae. Eggs small to medium, size 0.40–0.75 × 0.25–0.5 mm.

Type material. Neotype: 1 ovig. ♀ (CL 7.1 mm), MNHN-IU-2009-2270 (ex MNHN-Na480), Maine-et-Loire, France [here designated].

Tunisia: 8 ♀♀ (1 ovig.) (CL 5.4–7.4 mm), Barrage Lebna (Fig. 1, stn 1), 21.3.2010, coll. S. Dhaouadi-Hassen; 2 ♀♀ (CL 6.0–6.8 mm), NHM 1515–1540.22.2.74, Ain Draham, Barrage Ben Metir (Fig. 1, stn 2), 22.2.1974. Algeria: 1 ♂ (CL 5.1 mm), NHM 1955.5.3.15–18, Algiers, Seybouse River (Fig. 1, stn 3), 3.5.1955; 11 ♀♀ (6 ovig.) (CL 5.0–8.0 mm) and 1 ♂ (CL 5.2 mm), NHM 1949.5.2.1–12, Beni Abbes, Saoura River (Fig. 1, stn 4), 2.5.1949, coll. H. Munro Fox. Morocco: 4 ♀♀ (1 ovig.) (CL 5.5–6.5 mm) and 1 ♂ (CL 5.0 mm), Moulouya River (Fig. 1, stn 5), 11.4.2011, coll. M. Melhaoui; 1 ♀ (CL 6.9 mm) and 4 ♂♂ (CL 5.2–5.6 mm), NHM 1953.12.2.12–15, Krumane River (Fig. 1, stn 6), 22.7.1952, coll. J. Phillipson. Portugal: 21 ♀♀ (12 ovig.) (CL 5.8–7.3 mm) and 11 ♂♂ (CL 5.0–5.7 mm), Algarve, São Barnabé River (Odelouca River) (Fig. 1, stn 7), 23.7.1988, coll. C. d' Udekem d' Acoz; 7 ♀♀ (6 ovig.) (CL 6.2–7.7 mm) and 5 ♂♂ (CL 5.0–5.2 mm), NHM 1971.105, Portimao, Odelouca River (Fig. 1, stn 8), 1970; 18 ♀♀ (4 ovig.) (CL 5.5–8.0 mm) and 3 ♂♂ (CL 5.0–5.1 mm), NHM 1986.261, Bordeira River (Fig. 1, stn 9), 5.3.1985, coll. J. Paula; 5 ♀♀ (4 ovig.) (CL 7.0–8.1 mm) NHM 1880.36, Sintra, Colares River (Fig. 1, stn 10), 1880; 15 ♀♀ (3 ovig.) (CL 5.8–7.9 mm) and 5 ♂♂ (CL 5.3–6.1 mm), Coimbra, Ceira River (Fig. 1, stn 11), 24.5.2010, coll. V. Ferreira. Spain: 2 ♀ (CL 6.5–8.0 mm), Veta la Arena, Guadiamar River (Fig. 1, stn 12), 8.5.2006, coll. C. Lejeusne; 5 ♀♀ (CL 6.1–6.7 mm) and 17 ♂♂ (CL 5.0–6.5 mm), Cadiz, Guadalete River (Fig. 1, stn 13), 2000, coll. A. Rodriguez; 3 ♀♀ (CL 5.1–6.3 mm), Segura River (Fig. 1, stn 14), 28.9.2001, coll. J.L. Moreno Alcaraz; 10 ♀♀ (1 ovig.) (CL 6.1–7.5 mm) and 1 ♂ (CL 5.5 mm), Mundo River (Fig. 1, stn 15), 18/27.9.2001, coll. J.L. Moreno Alcaraz; 2 ♀♀ (CL 6.6–7.7 mm) and 1 ♂ (CL 5.5 mm), Villalva de la Sierra, Jucar River, 40°07.99'N, 02°08.38'W (Fig. 1, stn 16), 16.8.2001, coll. J.L. Moreno Alcaraz; 7 ♀♀ (CL 5.1–6.4 mm) and 1 ♂ (CL 5.3 mm), Ossa de Montiel, Vado Blanco River, 38°54.60'N, 02°48.03'W (Fig. 1, stn 17), 3.10.2001, coll. J.L. Moreno Alcaraz; 3 ♀♀ (CL 5.7–6.5 mm), El Torno, Bullaque River, 39°14.36'N, 04°15.57'W (Fig. 1, stn 18), 11.10.2001, coll. J.L. Moreno Alcaraz; 2 ♀♀ (CL 7.2–7.7 mm), Canavera, Guadiella River, 40°25.36'N, 02°28.95'W (Fig. 1, stn 19), 14.8.2001, coll. J.L. Moreno Alcaraz; 3 ♀♀ (CL 6.2–8.0 mm), Abanades, Tajuna River (Fig. 1, stn 20), 7.8.2001, coll. J.L. Moreno Alcaraz; 3 ♀♀ (1 ovig.) (CL 6.3–7.2 mm) and 6 ♂♂ (CL 5.5–6.5 mm), Henares River, (Fig. 1, stn 21), 1.8.2001, coll. J.L. Moreno Alcaraz; 1 ovig. ♀ (CL 7.4 mm), Naharros, Canamares River, 41°09.10'N, 02°55.14'W (Fig. 1, stn 22), 30.7.2001, coll. J.L. Moreno Alcaraz; 2 ovig. ♀♀ (CL 7.3–7.8 mm), Puebla de Valles, Jarama River (Fig. 1, stn 23), 31.7.2001, coll. J.L. Moreno Alcaraz; 1 ♀ (CL 5.9 mm) and 1 ♂ (CL 5.1 mm) La Guardia, Cedron River, 39°48.26'N, 03°20.33'W (Fig. 1, stn 24), 6.9.2001, coll. J.L. Moreno Alcaraz; 1 ♀ (CL 5.2 mm), Escalona, Alberche River, 40°09.45'N, 04°25.04'W (Fig. 1, stn 25), 27.8.2001, coll. J.L. Moreno Alcaraz; 1 ♀ (CL 5.1 mm) and 2 ♂♂ (CL 5.3–5.7 mm), Tietar River (Fig. 1, stn 26), 28.8.2001, coll. J.L. Moreno Alcaraz; 9 ♀♀ (1 ovig.) (CL 5.1 mm) and 1 ♂ (CL 5.0 mm), Tagus River (Fig. 1, stn 27), 14.8.2001 and 5.9.2001, coll. J.L. Moreno Alcaraz; 1 ♂ (CL 5.5 mm), Calanda, Guadalope River (Fig. 1, stn 28), 25.5.2004, coll. J. Oscoz; 1 ♀ (CL 7.2 mm) and 1 ♂ (CL 5.1 mm), Escatron, Martin River (Fig. 1, stn 29), 24.5.2001, coll. J. Oscoz; 1 ♀ (CL 5.6 mm) and 3 ♂♂ (CL 5.3–5.6 mm), Murillo de Gallego, Gallego River (Fig. 1, stn 30), 7.8.2007, coll. J. Oscoz; 1 ovig. ♀ (CL 6.5 mm), Gurrea de Gallego, Soton River (Fig. 1, stn 31), 14.6.2006, coll. J. Oscoz; 1 ♂ (CL 6.2 mm), Lumbier, Irati River (Fig. 1, stn 32), 8.7.2005, coll. J. Oscoz; 2 ovig. ♀♀ (CL 6.9–7.5 mm) and 4 ♂♂ (CL 5.2–5.8 mm), Aspurz, Salazar River (Fig. 1, stn 33), 3.7.2007, coll. J. Oscoz; 1 ovig. ♀ (CL 6.5 mm) and 1 ♂ (CL 5.2 mm), Ripodas, Areta River (Fig. 1, stn 34), 3.7.2007, coll. J. Oscoz; 5 ♀♀ (4 ovig.) (CL 5.0–7.5 mm) and 2 ♂♂ (CL 5.6 mm), Castejon, Alfaro, Tudela, Ebro River (Fig. 1, stn 35), 11/12.7.2007, coll. J. Oscoz; 6 ♀♀ (5 ovig.) (CL 7.0–8.6 mm), San Adrian, Ega River (Fig. 1, stn 36), 27.6.2007, coll. J. Oscoz; 1 ovig. ♀ (CL 7.3 mm) and 2 ♂♂ (CL 5.2–5.5 mm), Marcilla, Aragon River (Fig. 1, stn 37), 28.6.2007, coll. J. Oscoz; 2 (1 ovig.) ♀♀ (CL 8.2–8.5 mm) and 2 ♂♂ (CL 5.6–6.5 mm), Urroz, Erro River (Fig. 1, stn 38), 25.5.2007, coll. J. Oscoz; 1 ovig. ♀ (CL 7.5 mm) and 2 ♂♂ (CL 5.8–6.0 mm), Mendigorria, Salado River (Fig. 1, stn 39), 14.6.2007, coll. J. Oscoz; 1 ovig. ♀ (CL 7.6 mm), Puentelarreina, Arga River (Fig. 1, stn 40), 20.6.2007, coll. J. Oscoz; 1 ♀ (CL 7.2 mm), Iraneta, Arakil River (Fig. 1, stn 41), 20.6.2007, coll. J. Oscoz; 1 ♀ (CL 7.4 mm), Palazuelos, Jerea River (Fig. 1, stn 42), 1.6.2004, coll. J. Oscoz; 3 ovig. ♀♀ (CL 7.3–8.0 mm) and 2 ♂♂ (CL 5.3–5.5 mm), NHM 1955.10.5.2–6 and NHM 1957.8.12.69–75, Barcelona, Llobregat River (Fig. 1, stn 43), 5.10.1955 and 12.8.1955; 8 ♂♂ (CL 5.2–6.1 mm), Bascara, Fluvia River (Fig. 1, stn 44), 4.2.2005, coll. M.L. Zettler; 3 ♀♀ (CL 5.6–6.6 mm), NHM 1955.10.5.8–10, Gerona, Lake of Banyoles (Fig. 1, stn 45), 5.10.1955. France: 30 ♀♀ (18 ovig.) (CL 5.0–7.0 mm) and 20 ♂♂ (CL 5.0–5.2 mm), Merville, Garrone River (Fig. 1, stn 46), 25.8.2004, coll. R. Liasko and S. Combes; 2 ♀♀ (CL 5.5–6.5 mm), NHM 1955.5.3.11–14, Maine et Loire, Loire River (Fig. 1, stn 47), 3.5.1955; 2 ♀♀ (CL 6.6–7.0 mm), Angers, Sarthe River (Fig. 1, stn 48), 20.9.2000, coll. P. Noél; 2 ♀♀ (CL 5.1–5.6 mm), Mayenne River (Fig. 1, stn 49), 20.9.2000, coll. P. Noél; 3 ♀♀ (CL 6.3–6.5 mm), NMW 467, Rennes, Vilaine River (Fig. 1, stn 50), coll. G. Laponge. Belgium: 31 ♀♀ (8 ovig.) (CL 5.2–8.3 mm) and 7 ♂♂ (CL 5.0–6.0 mm), Ombret, Meuse River, (Fig. 1, stn 51), 3.8.1979, coll. C. d' Udekem d' Acoz. Germany: 1 ♂ (CL 5.2 mm) Berlin, Tegel Lake, 52°34.98'N, 13°16.44'E (Fig. 1, stn 52), 13.9.1995, coll. K. Rudolph and M.L. Zettler; 4 ♀♀ (CL 5.7–7.0 mm) and 1 ♂ (CL 5.0 mm), Havel River (Fig. 1, stn 53), 52°23.82'N, 12°17.04'E, 26.8.2005 (Saxony–Anhalt) and 52°29.82'N, 12°24.30'E, 27.8.2005 (Brandenburg), coll. M.L. Zettler. Austria: 1 ♀ (CL 7.4 mm), NMW 18315, Danube River (Fig. 1, stn 54), 8.10.1998, coll. Zipel and Melcher. Italy: 2 ♂♂ (CL 5.0–5.7 mm), Centa River (Fig. 1, stn 55), 28.5.1989, coll. C. Froglia; 4 ♀♀ (CL 5.3–5.8 mm) and 1 ♂ (CL 5.6 mm), Nestore River (Fig. 1, stn 56), 11.11.1974, coll. C. Froglia; 2 ♂♂ (CL 5.2–5.6 mm), Ponte Nuovo, Chiascio River, (Fig. 1, stn 57), 9.9.1975, coll. Cianficoni; 2 ovig. ♀♀ (CL 7.0–7.5 mm) and 1 ♂ (CL 5.2 mm), Nera River (Fig. 1, stn 58), 5.6.1971, coll. Moretti; 5 ♀♀ (CL 6.2–6.8 mm) and 7 ♂♂ (CL 5.0–6.3 mm), Tiber River (Fig. 1, stn 59), 10.10.1975 (Nestore), 14.10.1975 (Orte), 13.11.1975 (Umbertide), coll. Cianficoni. Sicily: 1 ovig. ♀ (CL 7.5 mm) and 4 ♂♂ (CL 5.4–5.9 mm), San Bartolomeo, Rosmarino River (Fig. 1, stn 60), 13.5.1986, coll. C. Froglia; 2 ♀♀ (CL 5.8–6.4 mm) and 1 ♂ (CL 5.5 mm), Simeto River (Fig. 1, stn 61), 1.9.1978, coll. C. Froglia. Sardinia: 7 ♀♀ (4 ovig.) (CL 5.5–7.2 mm) and 2 ♂ (CL 5.0 mm), unknown locality (Fig. 1, stn 62), 13.9.1977, coll. Cav; 2 ♀ (CL 6.7–7.6 mm) and 1 ♂ (CL 5.6 mm), unknown locality, coll. R.B. Manning. Corsica: 3 ♀♀ (1 ovig.) (CL 6.3–6.9 mm) and 1 ♂♂ (CL 5.0 mm), Favello, Taravo River (Fig. 1, stn 63), 10.8.2003, coll. M.L. Zettler; 5 ♂♂ (CL 5.0–5.8 mm), Propriano, Rizzanese River (Fig. 1, stn 64), 13.8.2003, coll. M.L. Zettler; 2 ♀♀ (CL 7.2–7.9 mm) and 4 ♂♂ (CL 5.3–6.0 mm), Bravone, Bravone River, 42°12.36'N, 09°32.10'E (Fig. 1, stn 65), 16.8.2003, coll. M.L. Zettler.

Rostrum long, dorsal margin straight or slightly curved in the middle and pointed upwards, 3.79–8.70, mostly (82% of the individuals examined) 4.64–6.50, × as long as high, shorter, equal to, or longer than scaphocerite. From 17 to 36 (21–28 in 86% of the individuals examined) pre orbital teeth on dorsal margin of rostrum arranged to tip. One to five, most frequently (90% of the individuals examined) 2–4, post orbital teeth and 1–13, most often (88% of the individuals examined) 4–9, teeth on ventral margin of rostrum. Carapace smooth with pterygostomial angle not protruding, rounded (Anastasiadou et al. 2006; Fig. 1). Pleuron of fifth abdominal segment pointed with an acute posterior angle. Telsonwith 2–4, most frequently (95% of the individuals examined) 3–4, pairs of dorsal spines arranged in curved fashion. Distal border of telson with 7–15, mostly (89%) 9–13, spines (4–7 pairs) arranged in a fan-like way. Outermost pair of spines shortest, similar to dorsal spines, adjacent pair stronger, terminating before the inner, finely setulose pairs (Anastasiadou et al. 2006; Figs 2A–B). Antennulary stylocerite with its tip failing to reach, reaching or overreaching distal margin of basal peduncle segment. Anterolateral lobe of basal segment short, round or pointed. Distal segment of antennular peduncle with 0–2, predominantly (93%) 1–2, spines (Anastasiadou et al. 2006; Fig. 2D). Basal lower endite of maxilla densely covered with long simple setae arranged in 15–22, mostly (84%) 17–20, oblique parallel rows. Endite of maxilla 1.39–1.88, most often (90%) 1.49–1.71, × as long as basal lower endite (Anastasiadou et al. 2006; Fig. 3C). Basal endite of first maxilliped reaching clearly beyond distal end of exopod (Anastasiadou et al. 2006; Fig. 3D). Distal one-third of terminal segment of third maxilliped bearing 0–8, (1–6 in 91% of the individuals examined), mesial spines and one subdistal lateral spine near the base of larger terminal spine, interpretable as dactylus (Anastasiadou et al. 2006; Fig. 3G). Armature along flexor margin of dactylus of third and fourth pereiopod consisting of 5–10 (6–8 in 95% of the individuals) and 5–10 (6–8 in 94% of the individuals) spines respectively. Merus of third and fourth pereiopod with 1–7 (3–5 in 95% of the individuals) and 2–6 (3–5 in 99% of the individuals) spines respectively (Anastasiadou et al. 2006; Figs 4C–D). Armature along flexor margin of dactylus of fifth pereiopod consisting of 18–43, mostly (87%) 25–35, spines (Anastasiadou et al. 2006; Figs 4E–F). Endopod of first male pleopod expanded proximally and with a distal portion elongated and tapering, often with a small protruding lobe in its outer subdistal part. Endopod with 14–30 (16–25 in 86% of the individuals examined), spines arranged on a slightly curved inner margin and 9–17 (10–15 in 92% of the individuals examined), setae arranged on outer margin (Anastasiadou et al. 2006; Fig. 5C, Anastasiadou et al. 2008; Fig. 5C). 133–848 eggs of 0.4–0.7 × 0.25–0.4 mm size.

Atyaephyra desmarestii is a large sized species with maximum carapace length to be 6.8 mm in ♂♂, 8.5 mm in ♀♀ and 8.6 mm in ovig. ♀♀.

Atyaephyra desmarestii can be differentiated from all other species of Atyaephyra by molecular characters, as demonstrated by the phylogenetic analysis of mtDNA COI sequences. Furthermore, 22 haplotypes from 30 different localities found in Atyaephyra desmarestii were not shared by any other species of the genus. Finally, it differs from all the other species in the following nucleotide positions in the COI gene of Atyaephyra desmarestii specimen Dour1 (Genbank accession number JX289920), position 213: cytosine (C), position 234: cytosine (C) and position 444: adenine (A).

Atyaephyra desmarestii is found in freshwater habitats of North Africa and West-central Europe (see material examined and Fig. 1).

Atyaephyra desmarestii has been exhaustively described and illustrated by Anastasiadou et al. (2006). Anastasiadou et al. (2008) also re-established and redescribed in detail Atyaephyra rosiana, a species currently considered as a synonym of Atyaephyra desmarestii. In the present paper the same material used for the redescriptions of Atyaephyra desmarestii and of Atyaephyra rosiana (Anastasiadou et al. 2006, 2008) was examined. Although Anastasiadou et al. (2006) stated that the “holotype” of Atyaephyra desmarestii could not be traced in French institutions, Bouvier (1913) clearly stated that he examined material from “Maine-et-Loire (H. Milne Edwards, probablement des cotypes de Millet)”. As Millet and H. Milne Edward were contemporary, and it seemed possible that H. Edwards may have asked for some specimens from the MNHN, this material was recently looked for in the MNHN collection, where the material listed in Bouvier (1913) is indeed still present (registration number Na480). However, there appears to be a discrepancy (and thus possible clarification) on the actual specimen label to this information. The specimen label (see Appendix: Fig. 3) provides the following information: (1) “Maine et Loire”, (2) “Caridina Desmarestii Millet”, (3) “A. Milne Edwards det.”, (4) “E.L. Bouvier ver. 1899” and (5) “A. Milne Edwards, 1900”. It is difficult to definitively interpret the label information in view of what Bouvier (1913), a contemporary of A. Milne-Edwards, wrote, as he may have had access to direct, personal information. However, the sample is herein interpreted as having belonged to the A. Milne-Edwards collection, who died in 1900 (1835–1900) and was then accessioned in the museum collection (label item 5), with the material being examined and verified, i.e “ver.” in 1899, by Bouvier (label item 4), but that the material originally was identified by A. Milne Edwards (label item 3), and that the material may not have been seen by H. Milne Edwards (although it may have passed from father to son without being recorded as such on the museum labels). It seems, therefore, impossible to certify that these are indeed syntypic specimens of Hippolyte Desmarestii Millet, 1831, as indicated by Bouvier (1913). However, in deference to Bouvier’s potential knowledge on the matter and in line with Recommendation 75A (ICZN, 1999), a neotype for Atyaephyra desmarestii is herein selected from this lot, the largest ovigerous female. The designation of a neotype is deemed justified under Art. 75 (ICZN, 1999), as (1) the taxon is involved in a complex nomenclatorial problem which cannot be solved without fixing the identity of the oldest name; (2) the taxon is differentiated from the other taxa in this complex by having 0–8 mesial spines on terminal segment of third maxilliped, the basal endite of first maxilliped clearly reaching beyond distal end of exopod, having 1–5 post orbital rostral teeth, having a not protruding, rounded pterygostomial angle and by the slightly curved endopod of first male pleopod with its distal part elongated and tapering; (3) the selected specimen is the largest (of only two) ovigerous females in lot MNHN-Na480; (4) the reasons the name-bearing types are considered lost (or the contrary cannot be conclusively proven) are given above (see also Anastasiadou et al. 2006); (5) the neotype is from the general locality (Maine et Loire) of the type locality of Atyaephyra desmarestii from which no other species is known and thus it corresponds morphologically and genetically with data presented herein and in Anastasiadou et al. (2006); (6) the neotype is selected from the “Maine et Loire” sample in Bouvier (1913), corresponding to the area mentioned in Millet (1831); and (7) the neotype has been selected from a sample already belonging to MNHN (Na480). Therefore, all conditions of Art. 75 are considered to be met and the selection of neotype is justified.

In light of the current revision of the species complex across Europe, North Africa and the Middle East, a nomenclatorial problem exists with the nomen, Atyaephyra desmarestii var. occidentalis Bouvier (1913), for which Bouvier (1913) did not designate a holotype. As such, the syntypic material of this variety (considered to be equivalent to a subspecies under Art. 45.6.4) includes all the material listed by Bouvier (1913) to have originated from North Africa and southern Europe, up to Macedonia. As such, this includes material from the Vardar region as summarily listed in Bouvier (1913), the area from which subsequently Atyaephyra desmarestii stankoi Karaman (1972) was described. As the name of Bouvier’s variety would take precedence over Atyaephyra stankoi as used in the present revision (a precedence which would cause considerable confusion), the herein selected neotype of Atyaephyra desmarestii (see above) is simultaneously selected as the lectotype of Atyaephyra desmarestii var. occidentalis Bouvier, 1913. This being fully justified by the inclusion of the “Maine et Loire” material in Bouvier (1913)’s type series. As a result of this action, the nomen Atyaephyra stankoi Karaman, 1972 can be used for the Macedonian taxon (as used herein), whilst Atyaephyra desmarestii var. occidentalis Bouvier, 1913 becomes a junior synonym of Atyaephyra desmarestii (Millet, 1831).

Bouvier (1913) also mentions he examined material from Coimbra (Portugal), with those particular specimens send by “Barboza” from the Museu Bocage under the name Atyaëphyra rosiana. He further indicates that these almost surely are cotypes from Brito Capello (“presque sûrement des cotypes”). These specimens are still present in the collection of MNHN (registration number Na509), with the label information (see Appendix: Fig. 4) corroborating the statement in Bouvier (1913) and as such are herein interpreted as syntypes of Atyaephyra rosiana de Brito Capello, 1867. Under ICZN Art. 75.8, the neotype selected by Anastasiadou et al. (2008) is thus set aside by the rediscovery of these syntypes. As the synonymy of Atyaephyra rosiana with Atyaephyra desmarestii seems certain at present, there appears currently no need to select a lectotype amongst the material. It should however be noted that the type locality of Atyaephyra rosiana de Brito Capello, 1867 reverts back to Coimbra (Portugal) and is no longer São Barnabe River, Algarve, as listed in De Grave & Fransen (2011) (see also García Muñoz et al. 2009).

Atyaephyra desmarestii can be distinguished among other characters from Atyaephyra stankoi, Atyaephyra orientalis and Atyaephyra thyamisensis sp. n. by the presence of 0–8 mesial spines (Anastasiadou et al. 2006; Fig. 3G) on the terminal segment of third maxilliped (vs. 10–38 in Atyaephyra orientalis, Atyaephyra stankoi and Atyaephyra thyamisensis sp. n.; Figs 4H, 6H, 8H respectively) and by the basal endite of first maxilliped reaching beyond distal end of exopod (Anastasiadou et al. 2006; Fig. 3D) (vs. basal endite fails to reach or reaches distal end of exopod in Atyaephyra orientalis, Atyaephyra stankoi and Atyaephyra thyamisensis sp. n.; Figs 4F, 6F, 8F respectively). Atyaephyra desmarestii is similar to Atyaephyra strymonensis sp. n. in having 0–8 mesial spines on the terminal segment of third maxilliped (Fig. 10H) but it can be discriminated by the presence of 1–5 post orbital rostral teeth (Anastasiadou et al. 2006; Fig. 1) (vs. no post orbital teeth present leaving short unarmed proximal gap in Atyaephyra strymonensis sp. n.; Fig. 9A).

Turkey: 3 ♀♀ (CL 4.8–5.0 mm), Antalya, Kirkgoz Spring (Fig. 1, stn 107), 21.6.2006, coll. M. Özbek; 7 ♀♀ (CL 4.5–5.5 mm), SMF 12174, Akbez, Karasu River (Fig. 1, stn 108), 22.9.1982, coll. R.K. Kinzelbach. Syria: 10 ♀♀ (3 ovig.) (CL 5.0–6.0 mm) and 4 ♂♂ (CL 4.0–5.0 mm), SMF 12050, below the dam of Ascharna, Orontes River (Fig. 1, stn 109), 30/31.3.1979, coll. R.K. Kinzelbach; 34 ♀♀ (15 ovig.) (CL 4.1–4.8 mm), SMF 12188, north of M’adan, Euphrates River (Fig. 1, stn 110), 17.8.1978, coll. R.K. Kinzelbach; 3 ♀♀ (2 ovig.) (CL 4.5–5.6 mm), SMF SYR8, Euphrates River (Fig. 1, stn 111), 15/16.6.1998, coll. R. Beck. Israel: 3 ♀♀ (2 ovig.) (CL 4.7–5.3 mm) and 2 ♂♂ (CL 3.9–4.0 mm), SMF IES 1189, Te’o Spring (Fig. 1, stn 112), 16.2.1977; 9 ♀♀ (CL 4.3–6.0 mm) and 4 ♂♂ (CL 3.9–4.0 mm), Hula Lake (Fig. 1, stn 113), 29.1.1981, coll. D. Eurth; 2 ovig. ♀♀ (CL 3.8–3.9 mm), NHM 1913.7.24.3–12, Kinneret Lake (Fig. 1, stn 114), 24.7.1913; 1 ♀ (CL 3.9 mm), Samakh, Kinneret Lake, 6.5.1986, coll. R. Ortal; 1 ♀ (CL 4.4 mm), Zaki River (Fig. 1, stn 115), 6.5.1986, coll. R. Ortal; 1 ♀ (CL 4.0 mm), Jordan River (Fig. 1, stn 116), 6.5.1981, coll. R. Ortal; 1 ♀ (CL 4.2 mm) and 1 ♂ (CL 3.8 mm), NHM 1938.1.26.8.12, Jordan River, 26.1.1938. Jordan: 2 ♀♀ (1 ovig.) (CL 4.0–4.9 mm), SMF 12057, Al-Azraq Oasis (Fig. 1, stn 117), 24.3.1977, coll. H. Damian. Iraq: 12 ♀♀ (CL 5.6–6.8 mm) and 3 ♂♂ (CL 4.5–4.8 mm), Basrah, Garmat Ali marsh (Fig. 1, stn 118), 24.2.1987, coll. A.H.Y. Al-Adhub; 1 ♀ (CL 5.2 mm), NHM 1919.11.14.5–20, Basrah, Shatt Al-Arab River (Robat creek) (Fig. 1, stn 119), 14.11.1919, coll. Capt. Boulenger; 1 ♂ (CL 4.2 mm), NHM 1919.4.28.2–3, Basrah, Shatt Al-Arab River (Robat creek), 28.4.1919, coll. P.J. Barraud; 4 ♀♀ (1 ovig.) (CL 5.2–5.5 mm) and 1 ♂ (CL 4.8 mm), Basrah, Shatt Al-Arab River (Fig. 1, stn 120), 2011, coll. M.D. Naser; 1 ovig. ♀, NHM 1919.11.12.11, Amarah, Tigris River (Fig. 1, stn 121), 12.11.1919, coll. J.O. Cooper Esq.

Rostrum long, slender, dorsal margin straight, slightly or strongly curved in the middle and pointed upwards or downwards, 6.0–10.0, most frequently (91% of the individuals examined) 6.5–9.25, × as long as high, shorter or equal to, or longer than scaphocerite (longer in 71% of the individuals examined). 14–29 (18–23 in 80% of the individuals) pre orbital teeth on dorsal margin of rostrum arranged to tip. 0–3, most often (85%) 1–3, post-orbital teeth. 3–13 teeth, mostly (96%) 4–10, arranged on ventral margin of rostrum (Fig. 3A). Carapace smooth with pterygostomial angle not protruding and rounded or bluntly produced (Figs 3B–C). Pleuron of fifth abdominal segment pointed ending in an acute or an obtuse posterior angle (Fig. 3D). Telsonwith 3–6, predominantly (93%) 4–5, pairs of dorsal spines arranged in curved fashion (Fig. 3E). Distal border of telson with 7–12, most often (91%) 8–10, spines (4–5 pairs) arranged in a fork-like or a fan-like way. Outermost pair of spines shortest, similar to dorsal spines, adjacent pair stronger terminating beyond, along with or before (beyond and along with in 64% of the individuals) the inner finely setulose pairs (Figs 3E–F). Basal segment of antennular peduncle with long stylocerite, with its tip failing to reach, reaching or overreaching the distal end of basal segment. Anterolateral lobe of basal segment short and pointed (Figs 3H–I). Distal segment of antennular peduncle with 0–3, most often (93%) 1–2, spines (Fig. 3G). Basal lower endite of maxilla densely covered with long simple setae arranged in 11–16 (12–15 in 93% of the individuals) oblique parallel rows. Endite of maxilla 1.75–2.20, mostly (93%) 1.81–2.07, × as long as basal lower endite (Fig. 4G). Basal endite of first maxilliped failing or reaching to distal end of exopod distal margin (Fig. 4F). Distal one-third of terminal segment of third maxilliped bearing 10–36 (14–31 in 84% of the individuals), mesial spines and one subdistal lateral spine near the base of larger terminal spine (Fig. 4H). Armature along flexor margin of dactylus of third and fourth pereiopod consisting of 6–11 (7–10 in 97% of the individuals) and 7–11 (8–10 in 89% of the individuals) spines (including terminal spine) respectively (Figs 4B, 4D). Merus of third and fourth pereiopod with 6–10 (7–9 in 85% of the individuals) and 5–9 (6–7 in 83% of the individuals) spines respectively (Figs 4A, 4C). Dactylus of fifth pereiopod with 33–55 (36–49 in 83% of the individuals) spines arranged in comb-like fashion on flexor margin (Fig. 4E). Endopod of first male pleopod expanded proximally with a distal portion stout and not tapering, often, with a, large protruding lobe in its outer subdistal part. Endopod with 13–38 spines arranged on a strongly curved inner margin and 5–8 setae arranged on outer margin (Fig. 4I, Bouvier et al. 1913: Fig. 1). 32–158 eggs of 0.5–0.75 × 0.35–0.5 mm in size.

Atyaephyra orientalis is a small-medium sized species of Atyaephyra, with maximum carapace length to be 4.8 mm in ♂♂, 6.8 mm in ♀♀ and 5.5 mm in ovig. ♀♀.

Atyaephyra orientalis can be differentiated from all other species of Atyaephyra by molecular characters, as demonstrated by the phylogenetic analysis of mtDNA COI sequences. Additionally, 5 haplotypes, each from a different location, found in Atyaephyraorientalis were not shared by any other species of the genus. It also differs from all the other species in the following nucleotide positions in the COI gene of Atyaephyra desmarestii specimen Dour1, position 273: guanine (G), position 276: guanine (G) and position 369: cytosine (C).

Atyaephyra orientalis is found in freshwater habitats of Middle East, from Turkey to Iraq (see material examined and Fig. 1).

Bouvier (1913) after examining the Atyaephyra material deposited in the MNHN collections he assigned it into two varieties (Atyaephyra desmarestii var. orientalis and Atyaephyra desmarestii occidentalis) based mainly on differences observed in the endopod of first male pleopod. Atyaephyra desmarestii var. orientalis was originally described from Syria (from Orontes River, near the Lake Qattinah (Lake Homs), from a stream in Kousseir (probably Qoussair) near Damascus and from Barada River, Ataibe, East of Damascus) and was elevated to subspecies level by Holthuis (1961). Apart from Atyaephyra desmarestii orientalis, a second subspecies, Atyaephyra desmarestii mesopotamica, was found to exist in the Middle East and was described by Al-Adhub (1987). Al-Adhub (1987) described the new subspecies based on the presence of a distinct subterminal process (vs. absent from Atyaephyra desmarestii orientalis and Atyaephyra desmarestii desmarestii) and the presence of 50 spines on dactylus of fifth pereiopod (vs. 40 in Atyaephyra desmarestii orientalis and Atyaephyra desmarestii desmarestii). Furthermore he noticed that the rostrum of Atyaephyra desmarestii mesopotamica resembles that of Atyaephyra desmarestii desmarestii from Greece but differs in having the distal ventral part always devoid of teeth. Indeed the individuals from Shatt Al-Arab River had the highest number of spines on dactylus of fifth pereiopod ranging from 41–55 but specimens from the River Orontes were also found with up to 47 spines (33–47). Additionally, male individuals having endopod with a distinct subterminal process were found again in River Orontes as well as in other Middle East Rivers. Gorgin (1996), after studying 150 males from two different localities in Iran found individuals with a distinct subterminal process and without inside the same population. Finally, specimens from Greece belonging to Atyaephyra stankoi (as the sample of Holthuis to which Al-Adhub refers to) were found to be also devoid of teeth in the distal part of the rostrum. Even in the illustration included in Holthuis (1961) work, the Greek specimen is devoid of teeth in the distal part of the ventral margin. Although the genetic distances within the Atyaephyra orientalis phylogroup were high (0.9%–10.2%) no firm conclusion could be drawn whether the hypothesis of multiple species is valid or not. Sequences from Orontes River (topotypical location of Atyaephyra desmarestii orientalis) and from Shatt Al-Arab River (topotypical location of Atyaephyra desmarestii mesopotamica) presented a noticeable mean genetic divergence (5.0%) but still not strong enough to support the hypothesis of different species. Detailed future studies on the morphological and genetic variability within the Atyaephyra distributed throughout the Middle East will help clarify the relationships between the populations in this region. However, only one species is currently considered to exist, Atyaephyra orientalis. Therefore, Atyaephyra desmarestii mesopotamica is here proposed as a synonym.

Atyaephyra orientalis appears to be morphologically more similar to Atyaephyra stankoi and Atyaephyra thyamisensis sp. n. by sharing characters such as the presence of numerous mesial spines (10–38) on terminal segment of third maxilliped (Figs 4H, 6H, 8H). It also shares in common with the other two species the presence of fewer rows of setae (12–16) on basal lower endite of maxilla, the endite of maxilla being 1.75–2.24 × as long as basal lower endite (Figs 4G, 6G, 8G) and basal endite of first maxilliped failing or reaching to distal end of exopod distal margin (Figs 4F, 6F, 8F). Atyaephyra orientalis can be separated from Atyaephyra thyamisensis sp. n. and Atyaephyra stankoi by the presence of a pointed antennular lobe (Figs 3H–I) (vs. round in Atyaephyra stankoi and Atyaephyra thyamisensis sp. n. Figs 5H, 7H). Further, Atyaephyra orientalis can be distinguished by the strongly curved and distally stout and not tapering endopod of male first pleopod (Fig. 4I) (vs. slightly curved and distally more or less elongated but always tapering in Atyaephyra stankoi, Fig. 6I; slightly or strongly curved but always its distal part is elongated and tapering (ribbon shaped) in Atyaephyra thyamisensis sp. n., Fig. 8I). Atyaephyra orientalis differs from the other four species of Atyaephyra in having 10–36 spines on terminal segment of third maxilliped (Fig. 4H) (vs. 0–8 in Atyaephyra desmarestii, Atyaephyra strymonensis sp. n., Atyaephyra acheronensis sp. n. and Atyaephyra tuerkayi sp. n. Figs 10H, 12H, 14H).

Type material. Neotype: NHM 2012.1475, adult ♀ (CL 6.0 mm), Greece–F.Y.R.O.M., Doirani Lake, (Fig. 1, stn 99), among aquatic plants, 9.11.1992, coll. S. Jovanovich and E. Stojkoska [here designated].

Greece: 4 ♀♀ (CL 5.4–5.9 mm), Peloponnesus, Alfeios River (Fig. 1, stn 82), 24.9.2001, coll. Ch. Anastasiadou; 4 ♀♀ (CL 5.4–5.7 mm), Aitoloacarnania, Ozeros Lake (Fig. 1, stn 83), 22.11.2001, coll. Ch. Anastasiadou; 2 ovig. ♀♀ (CL 5.5–7.0 mm), Aitoloakarnania, Aitoliko, Acheloos River (Fig. 1, stn 84), 4.4.2002, coll. Ch. Anastasiadou; 3 ♀♀ (CL 5.0–5.5 mm), Aitoloakarnania, Trichonida Lake (Fig. 1, stn 85), 22.10.2001, coll. Ch. Anastasiadou; 4 ♀♀ (CL 5.1–6.5 mm) Aitoloacarnania, Lysimachia Lake (Fig. 1, stn 86), 22.11.2001, coll. Ch. Anastasiadou; 1 ♀ (CL 6.9 mm) and 2 ♂♂ (CL 5.1–5.3 mm), Thessalia, Tavropou Lake (Fig. 1, stn 87), 14.11.2001, coll. Ch. Anastasiadou; 17 ♀♀ (CL 6.0–8.0) and 2 ♂♂ (CL 5.0 mm), Thessalia, Enipeas River (Fig. 1, stn 88), 14.10.2001, coll. Ch. Anastasiadou; 3 ♀♀ (CL 6.5–7.6 mm) and 1 ♂ (CL 5.5 mm), ZMAUTH G1-910, Thessalia, Mati Tyrnavou Lake (Fig. 1, stn 89), 15.11.1977, coll. A. Koukouras; 1 ♀ (CL 6.8 mm) and 1 ♂ (CL 5.2 mm) Thessalia, Pineios River (Fig. 1, stn 90), 15.11.2001, coll. Ch. Anastasiadou; 1 ♀ (CL 7.0 mm), Thessalia, Lithaios River (Fig. 1, stn 91), 14.11.2001, coll. Ch. Anastasiadou; 5 ♀♀ (CL 6.0–7.0 mm) and 1 ♂ (CL 5.0 mm), Thessalia, Gritsas River (Fig. 1, stn 92), 15.11.2001, coll. Ch. Anastasiadou; 3 ♀♀ (CL 6.0–6.7 mm), Macedonia, Aliakmonas River (Fig. 1, stn 93), 9.9.1974 and 26.11.1978; 4 ♀♀ (2 ovig.) (CL 5.7–6.8 mm), ZMAUTH G1-1005, Macedonia, Vegoritida Lake (Fig. 1, stn 94), 17.6.1968; 4 ♀♀ (1 ovig.) (CL 5.5–6.3 mm), ZMAUTH G1-1018, Thessalia, Agra Lake (Fig. 1, stn 95), 17.6.1968, coll. P. Economides; 12 ♀♀ (CL 5.5–7.0 mm) and 3 ♂♂ (CL 5.0–5.5 mm), Thessalia, Edessaios River (Fig. 1, stn 96), 19.10.2001, coll. Ch. Anastasiadou; 5 ♀♀ (CL 5.0–5.5 mm) and 1 ♂ (CL 5.0 mm), Thessalia, Kariotissa, Moglenitsa River (Fig. 1, stn 97), 18.10.2001, coll. Ch. Anastasiadou; 4 ♀♀ (CL 6.0–7.0 mm) and 1 ♂ (CL 5.0 mm), ZMAUTH G1-988, Macedonia, Axios River (Fig. 1, stn 98), 16.7.1971, coll. P. Economides; 11 ♀♀ (CL 5.9–7.3 mm) and 1 ♂ (CL 5.1 mm), Macedonia, Richios River (Fig. 1, stn 100), 26.10.01, coll. Ch. Anastasiadou; Greece–F.Y.R.O.M.: 4 ♀♀ (CL 5.0–5.7 mm), Doirani Lake, (Fig. 1, stn 99), 9.11.1992, coll. S. Jovanovich and E. Stojkoska.

Rostrum long, slender, dorsal margin straight or slightly curved in the middle and pointed upwards, 6.12–8.67, mostly (83% of the examined individuals) 6.25 to 7.54, × as long as high, shorter, equal to, or longer than scaphocerite (longer in 76% of the individuals examined). From 17 to 28 (19–27 in 91% of the individuals) pre orbital teeth on dorsal margin of rostrum arranged up to tip. 0–3, predominantly (96%) 1–3, post-orbital teeth. 2–8, most often (96%) 2–6, teeth arranged on ventral margin of rostrum (Fig. 5A). Carapace smooth with pterygostomial angle not protruding, rounded (Fig. 5B). Pleuron of fifth abdominal segment usually pointed ending in an obtuse (ending in an acute angle in 11% of the individuals) posterior angle (Figs 5C–D). Telsonwith 3–6, most often (93%) 5–6, pairs of dorsal spines arranged in curved fashion (Fig. 5E). Distal border of telson with 6–11, mostly (87%) 8–10, spines (3–6 pairs), arranged in a fork-like pattern. Outermost pair of spines shortest, similar to dorsal spines, adjacent pair stronger terminating beyond (or along with) the inner finely setulose pairs (Figs 5E–F). Basal segment of antennular peduncle with long stylocerite, with its tip failing to reach, reaching or overreaching the distal end of basal segment. Anterolateral lobe of basal segment short and rounded (Fig. 5H). Distal segment of antennular peduncle with 1–4, mostly (93%) 1–3, spines (Fig. 5G). Basal lower endite of maxilla densely covered with long simple setae arranged in 12–16, (13–15 in 89% of the individuals), oblique parallel rows. Endite of maxilla 1.78–2.08, mostly (89%) 1.84–1.99, × as long as basal lower endite (Fig. 6G). Basal endite of first maxilliped failing or reaching to distal end of exopod (Fig. 6F). Distal one-third of terminal segment of third maxilliped bearing 11–35, frequently (85%) 16–28, mesial spines and one subdistal lateral spine near the base of larger terminal spine (Fig. 6H). Armature along flexor margin of dactylus of third and fourth pereiopod consisting of 7–11 (7–9 in 98% of the individuals) and 7–10 (7–9 in 98% of the individuals) spines (including terminal spine) respectively (Figs 6B, 6D). Merus of third and fourth pereiopod with 3–8 (4–6 in 83% of the individuals examined) and 2–6 (3–5 in 88% of the individuals) spines respectively (Figs 6A, 6C). Dactylus of fifth pereiopod with 26–47, most often (80%) 32–41, spines arranged in comb-like fashion on flexor margin (Fig. 6E). Endopod of first male pleopod expanded proximally and with a distal portion either elongated (ribbon shape) or more stout but always tapering. Endopod with 13–17 spines arranged on a slightly curved inner margin and 7–12 setae arranged on the outer margin (Fig. 6I). 96–195 eggs of 0.6–0.7 × 0.4 mm in size.

Atyaephyra stankoi is a large sized species with maximum carapace length of 5.50 mm in ♂♂, 7.60 mm in ♀♀ and 6.8 mm in ovig. ♀♀.

Atyaephyra stankoi can be distinguished from all other species of Atyaephyra by molecular characters, as shown by the phylogenetic analysis of mtDNA COI sequences, such as the two unique Atyaephyra stankoi haplotypes. Furthermore, it differs from all the other species in the following nucleotide positions in the COI gene of Atyaephyra desmarestii specimen Dour1, position 192: cytosine (C), position 282: adenine (A), position 320: cytosine (C), position 342: cytosine (C) and position 423: cytosine (C).

Atyaephyra stankoi is found in freshwater habitats in the mainland of West-central Greece and South F.Y.R.O.M. (see material examined and Fig. 1).

Bouvier (1913) assigned the material of MNHN originating from Portugal, France, Corsica, Macedonia, Tunisia, Algeria and Morocco to var. occidentalis while the material from Syria he assigned to var. orientalis. The material from Macedonia was collected from the region of Vardar (Axios) north of Thessaloniki, from the Lake of Amatovo (drained in the early twentieth century) near Kirdzalar (today called Adendron). The two varieties described by Bouvier were elevated in subspecies level by Holthuis (1961) and the var occidentalis was re-named to Atyaephyra desmaresii desmarestii since it contained the name-bearing type of the species. Few years later, Karaman (1972) described a new subspecies from Doirani Lake which is part of the Vardar (Axios) basin and named it Atyaephyra desmarestii stankoi ignoring the available name of Bouvier’s (Atyaephyra desmarestii var. occidentalis). However, after designating a neotype of Atyaephyra desmarestii from Bouvier’s material the nomen Atyaephyra desmarestii var. occidentalis becomes unavailable since it becomes a junior synonym of Atyaephyra desmarestii (see Atyaephyra desmarestii remarks) and thus the nomen Atyaephyra stankoi can be used for the Macedonian taxon (as used herein).

Efforts made to trace Karaman’s type material in the MMNH were unsuccessful. According to the director of the Museum, Dr Petkovski S. (pers. comm.), Karaman’s material is considered lost after a fire that took place in the Museum.

A neotype for Atyaephyra stankoi is proposed for reasons of taxonomic clarification and stability, as foreseen by Art. 75 (ICZN, 1999). The neotype will contribute to the stability of the taxonomic status of the species and avoid further confusion due to nomenclature (see also Atyaephyra desmarestii remarks). Furthermore, it incorporates novel characteristics that distinguish it from the remaining Atyaephyra species such as: having 11–35 mesial spines on terminal segment of third maxilliped, basal endite of first maxilliped failing or reaching to distal end of exopod, distal boarder of telson with spines arranged in a fork-like pattern, a rounded antennular lobe, a pterygostomial angle not protruding, and a slightly curved and distally more or less elongated but always tapering endopod of male first pleopod. The name-bearing types are considered lost while the neotype has been collected from Doirani Lake, the same locality from where Karaman (1972) collected Atyaephyra desmarestii stankoi type material and it will replace the lost type material.

Atyaephyra stankoi is similar to Atyaephyra thyamisensis sp. n. in having: 11–38 mesial spines on terminal segment of third maxilliped (Figs 6H, 8H), 12–16 rows of setae on basal lower endite of maxilla (Figs 6G, 8G), 3–6 pairs (mostly 4–5) of spines on distal boarder of telson with the second pair to be the strongest and terminating beyond (or along with) the other pairs arranged in a fork-like pattern (Figs 5E–F, 7E–F), a rounded antennular lobe (Figs 5H, 7H) and the basal endite of first maxilliped failing or reaching to distal end of exopod (Figs 6F, 8F). Atyaephyra stankoi differs from Atyaephyra thyamisensis sp. n. in not having a sharply protruding pterygostomial angle (Figs 5B, 7B). Atyaephyra stankoi can be distinguished from Atyaephyra orientalis by the presence of a rounded antennular lobe (Fig. 5H) (vs. pointed in Atyaephyra orientalis; Figs 3H–I). Further, Atyaephyra stankoi can be distinguished by the slightly curved and distally more or less elongated but always tapering endopod of male first pleopod (Fig. 6I) (vs. strongly curved and distally stout and not tapering in Atyaephyra orientalis; Fig. 4I). Atyaephyra stankoi can be separated from Atyaephyra desmarestii, Atyaephyra strymonensis, Atyaephyra acheronensis and Atyaephyra tuerkayi by the presence of numerous mesial spines (11–35) on terminal segment of third maxilliped (Fig. 6H) (vs 0–8 mesial spines; Figs 10H, 12H, 14H).

Type material. Holotype: NHM 2012.1476, adult ovig. ♀ (CL 7.1 mm), Greece, Epirus, Thyamis River, 39°32.26'N, 20°09.76'E (Fig. 1, stn 76), among aquatic plants, 19.3.2005, coll. Ch. Anastasiadou; Allotype: NHM 2012.1477, adult ♂ (CL 5.3 mm), same data collection as holotype; Paratypes: NHM 2012.1478–1483, 4 ♀♀ (3 ovig.) (CL 6.0–6.8 mm) and 2 ♂♂ (CL 5.0–5.3 mm) same data collection as holotype. NHM 2012.1484–1485, 2 ♀ (CL 6.5–7.4 mm), Greece, Epirus, Louros River, 39°03.14'N, 20°46.26'E (Fig. 1, stn 72), among aquatic plants, 25.3.2012, coll. Ch. Anastasiadou. OUMNH.ZC 2012-08-001, 4 ♀♀ (2 ovig.) (CL 6.0–7.8 mm) and 2 ♂ (CL 5.2 mm) same data collection as holotype. SMF 43022, 4 ♀♀ (2 ovig.) (CL 5.8–7.1 mm) and 2 ♂♂ (CL 5.0–5.2 mm) same data collection as holotype. NHMW 25453, 4 ♀♀ (2 ovig.) (CL 5.5–7.5 mm) and 1 ♂♂ (CL 5.0 mm) same data collection as holotype

Greece: 2 ♀♀ (CL 5.2–5.5 mm), NHMW 462, Corfu Island (Fig. 1, stn 75), 1.9.1937, coll. Stephanides; 13 ♀♀ (1 ovig.) (CL 5.3–8.1 mm) and 8 ♂♂ (CL 5.2–6.2 mm), Epirus, Thyamis River (Fig. 1, stn 77), 20.5.2000 and 26.10.01, coll. Ch. Anastasiadou; 20 ♀♀ (15 ovig.) (CL 6.5–7.5 mm) and 3 ♂♂ (CL 5.0–5.7 mm), Epirus, Pamvotida Lake (Fig. 1, stn 78), 24.3.2006, coll. Ch. Anastasiadou; 20 ♀♀ (CL 5.0–7.0) and 8 ♂♂ (CL 5.0–5.5), Epirus, Ziros Lake (Fig. 1, stn 79), 28.10.2001, coll. Ch. Anastasiadou; 20 ♀♀ (CL 5.8–8.5 mm) and 4 ♂♂ (CL 5.2–6.4 mm), ZMAUTH D-334, Epirus, Filipiada, Louros River (Fig. 1, stn 80), 20.10.1977, coll. P. Economides; 15 ♀♀ (CL 5.5–8.0) and 6 ♂♂ (CL 5.0–6.0), Louros River (Fig. 1, stn 80), 28.10.2001, coll. Ch. Anastasiadou; 8 ovig. ♀♀ (CL 6.4–8.0 mm) and 6 ♂♂ (CL 5.3–6.2 mm), NHMW 465, Lefkada Island, Kaligoni, Vardas River (Fig. 1, stn 81), Aug.1929, coll. Beier; 3 ovig. ♀♀ (CL 7.3–8.0 mm) and 3 ♂♂ (CL 5.0–5.9 mm), NHMW 466, Lefkada Island, Kaligoni, Vardas River (Fig. 1, stn 81), 2.10.1932, coll. Beier.

Rostrum long, slender, dorsal margin straight or slightly curved in the middle and pointed upwards, shorter, equal to, or longer than scaphocerite, 6.0–9.50, most often (84% of the examined individuals) 6.33 to 8.76, × as long as high. 18–27 (18–24 in 91% of the individuals) pre orbital teeth on dorsal margin arranged up to tip of rostrum. 0–2, predominantly (84%) 1–2, post-orbital teeth. 4–10 teeth, most often (87%) 5–8, arranged on ventral margin of rostrum (Fig. 7A). Carapace smooth with pterygostomial angle bluntly produced (Fig. 7B). Pleuron of fifth abdominal segment pointed with an acute posterior angle (Fig. 7D). Telsonwith 5–8, mostly (97%) 5–7, pairs of dorsal spines arranged in curved fashion (Fig. 7E). Distal border of telson with 8–12, mostly (86%) 8–10, spines (4–6 pairs) arranged in fork-like pattern. Outermost pair of spines shortest, similar to dorsal spines, adjacent pair stronger terminating beyond (or along with) the finely setulose inner pairs (Figs 7E–F). Basal segment of antennular peduncle with long stylocerite, with its tip reaching or overreaching the distal end of basal segment. Anterolateral lobe of basal segment short and round (Fig. 7H). Distal segment of antennular peduncle with 1–6, frequently (92%) 2–4, spines (Fig. 7G). Basal lower endite of maxilla densely covered with long simple setae arranged in 12–16 (13–15 in 80% of the individuals), oblique parallel rows. Endite of maxilla 1.84–2.24, mostly (93%) 1.89–2.05, × as long as basal lower endite (Fig. 8G). Basal endite of first maxilliped failing or reaching to distal end of exopod (Fig. 8F). Distal third of terminal segment of third maxilliped bearing 13–38 (19–30 in 88% of the individuals) mesial spines and one subdistal lateral spine near the base of larger terminal spine (Fig. 8H). Armature along flexor margin of dactylus of third and fourth pereiopod consisting of 6–9 (7–9 in 97% of the individuals) and 6–10 (7–9 in 97% of the individuals) spines respectively (Figs 8B, 8D). Merus of third and fourth pereiopod with 3–7 (4–6 in 93% of the individuals) and 2–6 (4–5 in 96% of the individuals) spines respectively (Figs 8A, 8C). Dactylus of fifth pereiopod with 28–43, usually (82%) 32–40, spines arranged in comb-like fashion on flexor margin (Fig. 8E). Endopod of first male pleopod expanded proximally and with a distal portion elongated (ribbon shaped) and tapering. Endopod with 14–21 spines arranged on a slightly or strongly curved inner margin and 12–18 setae arranged on outer margin (Fig. 8I). 172–465 eggs of 0.60–0.7 × 0.40–0.45 mm in size.

Atyaephyra thyamisensis sp. n. is a large sized species with a maximum carapace length of 6.4 mm in ♂♂, 8.0 mm in ♀♀ and 8.1 mm in ovig. ♀♀.

Atyaephyra thyamisensis sp. n. is different from all the other species of Atyaephyra by molecular characters, as shown by the phylogenetic analysis of mtDNA COI sequences. The one haplotype found was unique in the genus. Furthermore, it differs from all the other species in the following nucleotide positions in the COI gene of Atyaephyra desmarestii specimen Dour1, position 172: cytosine (C), position 207: cytosine (C), position 249: guanine (G), position 258: cytosine (C), position 324: guanine (G), position 348: guanine (G) and position 387: cytosine (C).

Atyaephyra thyamisensis sp. n. is named after the Thyamis River, Greece, the type locality.

Atyaephyra thyamisensis sp. n. is found in fresh water habitats of North-west Greece as well as in the islands Corfu and Lefkada (see material examined and Fig. 1).

Remarks: Atyaephyra thyamisensis can be discriminated from Atyaephyra stankoi by the presence of a sharply protruding pterygostomial angle (Fig. 7B). It should be noted that this character has been observed to be missing from one side (either the left or the right) in some very large sized individuals (Fig. 7C). This character is shared by Atyaephyra orientalis (present in some populations) along with the presence of numerous spines (10–38) on terminal segment of third maxilliped (Figs 4H, 8H) and the presence of fewer rows of setae (12–16) on basal lower endite of maxilla (Figs 4G, 8G). The two species can be distinguished by the presence of a rounded antennular lobe in Atyaephyra thyamisensis (Figs 7G–H) (vs. pointed in Atyaephyra orientalis; Figs 3G–I). Further, Atyaephyra thyamisensis can be distinguished by the slightly or strongly curved endopod of first male pleopod having its distal part always elongated and tapering (ribbon shaped; Fig. 8I) (vs. strongly curved and distally stout and not tapering in Atyaephyra orientalis; Fig. 4I). Atyaephyra thyamisensis can be separated easily from the remaining three species of Atyaephyra by the presence of numerous mesial spines (13–38; Fig. 8H) on terminal segment of third maxilliped (vs. 0–8 mesial spinesin Atyaephyra desmarestii, Atyaephyra strymonensis, Atyaephyra acheronensis and Atyaephyra tuerkayi; Figs 10H, 12H, 14H).

Type material. Holotype: NHM 2012.1486, adult ovig. ♀ (CL 7.0 mm), Greece, Macedonia, Mylopotamos Springs (Strymonas River), 41°08.90'N, 24°04.29'E (Fig. 1, stn 102), among aquatic plants, 23.5.2011, coll. M. Christodoulou and M.S. Kitsos. Allotype: NHM 2012.1487, adult ♂ (CL 5.0 mm), same data collection as holotype. Paratypes: NHM 2012.1488–1492, 4 ♀♀ (CL 5.2–7.0 mm) and 1 ♂ (CL 5.0 mm) same data collection as holotype. OUMNH.ZC 2012-08-002 4 ♀♀ (1 ovig.) (CL 5.2–7.0 mm) and 1 ♂ (CL 5.0 mm) same data collection as holotype; SMF 43023 2 ♀♀ (CL 6.7–7.2 mm) and 1 ♂ (CL 5.0 mm) same data collection as holotype; NHMW 25454, 2 ♀♀ (CL 6.1–7.3 mm) same data collection as holotype.

Greece: 3 ♀♀ (CL 5.4–6.0 mm) Macedonia, Strymonas River (Fig. 1, stn 101), 1.10.2001, coll. Ch. Anastasiadou; 20 ♀♀ (13 ovig.) (CL 6.3–7.9 mm), Macedonia, Mylopotamos Springs (Fig. 1, stn 102), 4.4.2001, coll. Ch. Anastasiadou; 9 ♀♀ (CL 5.5–7.1 mm) and 5 ♂♂ (CL 5.1–5.3 mm) Macedonia, Agias Varvaras Springs (Fig. 1, stn 103), 4.4.2001, coll. Ch. Anastasiadou; 11 ♀♀ (4 ovig.) (CL 6.0–7.4 mm) and 3 ♂♂ (CL 5.1–5.3 mm), Macedonia, Kefalariou Springs (Fig. 1, stn 104), 4.5.2001, coll. Ch. Anastasiadou; 2 ♀♀ (CL 6.3 mm) and 2 ♂♂ (CL 5.3–5.6 mm), Thrace, Paradeisos, Nestos River (Fig. 1, stn 105), ZMAUTH G1-1024, 6.7.1972, coll. P. Economides; 14 ♀♀ (CL 5.5–7.3 mm) and 6 ♂♂ (CL 5.1–5.5 mm) Thrace, Kyrnos, Nestos River (Fig. 1, stn 106), 30.9.2002, coll. Ch. Anastasiadou.

Rostrum long, slender, dorsal margin straight or slightly curved in the middle and pointed upwards, 5.89–8.80, mostly (92% of the individuals examined) 6.75–8.80, × as long as high, shorter, equal to, or longer than scaphocerite. 10–29, frequently (92%) 14–23, pre orbital teeth on dorsal margin of rostrum arranged up to tip. Rostrum without post-orbital teeth, leaving a short unarmed proximal gap. With maximally five teeth, mostly (91%) up to three, arranged on ventral margin of rostrum (Fig. 9A). Carapace smooth with pterygostomial angle, not protruding, rounded (Fig. 9B). Pleuron of fifth abdominal segment pointed with an acute posterior angle (Fig. 9C). Telsonwith 2–7, predominantly (97%) 3–4, pairs of dorsal spines arranged in curved fashion (Fig. 9D). Distal border of telson with 11–15, usually (96%) 12–14, spines (6–8 pairs), arranged in fan-like way. Outermost pair of spines shortest, similar to dorsal spines, adjacent pair stronger terminating before the finely setulose inner pairs (Figs 9D–E). Basal segment of antennular peduncle with long stylocerite, with its tip failing to reach or reaching the distal end of basal segment. Anterolateral lobe of basal segment short and round (Fig. 9G). Distal segment of antennular peduncle with 0–1 but mostly (87%) with no spines (Fig. 9F). Basal lower endite of maxilla densely covered with long simple setae arranged in 12–17 (14–16 in 90% of the individuals), oblique parallel rows. Endite of maxilla 1.77–1.95, mostly (89%) 1.78–1.91, × as long as basal lower endite (Fig. 10G). Basal endite of first maxilliped failing, reaching or overreaching the distal end of exopod (reaching the end in 65% of the individuals) (Fig. 10F). Distal one-third of terminal segment of third maxilliped bearing 1–7 mesial spines and one subdistal lateral spine near the base of larger terminal spine (Fig. 10H). Armature along flexor margin of dactylus of third and fourth pereiopod consisting of 6–8 (7–8 in 96% of the individuals) and 7–8 spines (including terminal spine) respectively (Figs 10B, 10D). Merus of third and fourth pereiopod with 3–6 (3–5 in 90% of the individuals) and 3–5 spines respectively (Figs 10A, 10C). Dactylus of fifth pereiopod with 25–37, mostly (87%) 30–35, spines arranged in comb-like fashion on flexor margin (Fig. 10E). Endopod of first male pleopod expanded proximally and with a distal portion elongated and tapering, often, with a small, protruding lobe in its outer subdistal part. Endopod with 14–23 spines arranged on a slightly curved inner margin and 9–15 setae arranged on outer margin (Fig. 10I). 210–250 eggs of 0.50–0.70 × 0.40–0.50 mm in size.

Atyaephyra strymonensis sp. n. is a large sized species with maximum carapace length to be 5.6 mm in ♂♂, 7.9 mm in ♀♀ and 7.5 mm in ovig. ♀♀.

Atyaephyra strymonensis sp. n. is unique in the genus in having 2 haplotypes not found in any of the other species. Also, it differs from all the other species in the following nucleotide positions in the COI gene of Atyaephyra desmarestii specimen Dour1, position 201: cytosine (C), position 252: guanine (G), position 303: cytosine (C), position 309: thymine (T), position 318: guanine (G), position 319: adenine (A), position 367: thymine (T), position 393: cytosine (C) and position 453: thymine (T).

Atyaephyra strymonensis sp. n. is named after the Strymon (Strymonas) River, Greece, the type locality.

Atyaephyra strymonensis sp. n. is found in North-western Greece in the Rivers Strymon and Nestos (see material examined and Fig. 1).

Atyaephyra strymonensis sp. n. is unique in the combination of the following characters: (a) absence of post orbital teeth (Fig. 9A), (b) leaving a short unarmed proximal gap on dorsal surface of rostrum (Fig. 9A), (b) having a round anterolateral lobe on basal segment of antennular peduncle (Figs 9F–G), (c) having a not protruding, rounded pterygostomial angle (Fig. 9C), (d) endite of maxilla 1.77–1.95 × as long as basal lower endite (Fig. 10G) and having 1–7 mesial spines in the terminal segment of third maxilliped (Fig. 10H). Atyaephyra strymonensis is similar to Atyaephyra desmarestii, Atyaephyra acheronensis and Atyaephyra tuerkayi in having fewer spines in the terminal segment of third maxilliped. However Atyaephyra strymonensis differs by the absence of post-orbital teeth, leaving a short unarmed proximal gap on dorsal surface of rostrum and by the endite of maxilla being 1.77–1.95 × as long as basal lower endite (vs. 1.49–1.71). Atyaephyra strymonensis differs from Atyaephyra stankoi, Atyaephyra thyamisensis and Atyaephyra orientalis in having fewer mesial spines in the terminal segment of third maxilliped.

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).

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).

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 11D–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.

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 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).

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

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 limited number of specimens, it is postulated that Atyaephyra acheronensis sp. n. occurs in more rivers covering an area ranging from Croatia to Greece.

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).

Type material. Holotype: adult ♀ (CL 6.2 mm), SMF 43020, Syria, Nahr Al-Kabir River (Fig. 1, stn 122), at bridge near the coastal road, 5.3.1979, coll. R.K. Kinzelbach (Sequenced specimen: Nah1); Paratype: 1 ♀ (CL 7.1 mm), SMF 43021 same data as the holotype (Sequenced specimen: Nah2).

Rostrum long, dorsal margin slightly curved in the middle and pointed upwards 6.43–6.66 × as long as high, shorter than or equal to scaphocerite. 19–23 pre orbital teeth on dorsal margin of rostrum arranged up to tip. With two post orbital teeth and 4–7 teeth on ventral margin of rostrum (Fig. 13A). Carapace smooth with pterygostomial angle not protruding, rounded (Fig. 13B). Pleuron of fifth abdominal segment pointed with an acute posterior angle (Fig. 13C). Telsonwith four pairs of dorsal spines arranged in curved fashion (Fig. 13D). Distal border of telson with 9 spines (5 pairs) arranged in fan-like pattern. Outermost pair of spines shortest, similar to dorsal spines, adjacent pair stronger terminating before the finely setulose, inner pairs (Fig. 13E). 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. 13G). Distal segment of antennular peduncle with 1–2 spines (Fig. 13F). Basal lower endite of maxilla densely covered with long simple setae arranged in 18–20 oblique parallel rows. Endite of maxilla 1.58–1.59 × as long as basal lower endite (Fig. 14G). Basal endite of first maxilliped reaching clearly beyond distal end of exopod (Fig. 14F). Distal one-third of terminal segment of third maxilliped bearing 1–6 mesial spines and one subdistal lateral spine near the base of larger terminal spine (Fig. 14H). Armature along flexor margin of dactylus of third and fourth pereiopod consisting of 6–7 and 6–7 spines respectively (Figs 14B, 14D). Merus of third and fourth pereiopod with 4 and 3 spines respectively (Figs 14A, 14D). Armature along flexor margin of dactylus of fifth pereiopod consisting of 28 spines (Fig. 14E).

Atyaephyra tuerkayi is a large sized species with maximum carapace length to be 7.1 mm for ♀♀

A haplotype found in Atyaephyra tuerkayi sp. n. is not shared by any other species of Atyaephyra. Additionally, it differs from all the other species in the following nucleotide positions in the COI gene of Atyaephyra desmarestii specimen Dour1, position 174: guanine (G), position 207: adenine (A), position 246: adenine (A), position 318: thymine (T), position 321: adenine (A), position 339: adenine (A), position 357: cytosine (C), position 372: thymine (T), position 399: thymine (T), position 417: adenine (A) and position 441: cytosine (C). Finally, the mean genetic distances between Atyaephyra tuerkayi and the other species were ranging from 19.7% to 25.7% (Table 2).

Atyaephyra tuerkayi sp. n. is named after Professor Michael Türkay, in appreciation of his contribution to the study of Decapoda.

Atyaephyra tuerkayi sp. n. is found in the Nahr Al-Kabir River situated between Syria and Lebanon (see material examined and Fig. 1).

In addition to the type-material we investigated the morphology of the 23 female individuals (6 ovig.) and 7 males originating from Nahr Al-Kabir River (Fig. 1, stn 122; SMF 12189, SMF 12191, SMF 12192). All the individuals examined (including the sequenced ones) were morphologically identical. However, their placement to Atyaephyra tuerkayi, sp. n. has still to await sequencing. Since no male or ovigerous individual was sequenced observation regarding the form of the endopod of first male pleopod and number of eggs carried by the female were not included in the description. But observations were made in other individuals of the same sample and population and thus given here: endopod of first male pleopod expanded proximally and with a distal portion elongated and tapering, endopod with 9–16 spines arranged on a slightly curved inner margin and 9–11 setae arranged on outer margin. 430–450 eggs of 0.45–0.50 × 0.30–0.35 mm in size. Maximum carapace length to be 5.7 mm for ♂♂, 7.9 mm for ♀♀ and 7.6 mm for ovig. ♀♀.

Out of the 135 characters examined (see Appendix: Table 1) there were no morphological features distinguishing Atyaephyra tuerkayi sp. n. from Atyaephyra desmarestii and Atyaephyra acheronensis sp. n. However, Atyaephyra tuerkayi sp. n. can easily be distinguished from Atyaephyra orientalis, Atyaephyra stankoi and Atyaephyra thyamisensis by the presence of fewer mesial spines (Fig. 14H) (1–6) on terminal segment of third maxilliped (vs. 10–38 in Atyaephyra orientalis, Atyaephyra stankoi and Atyaephyra thyamisensis; Figs 4H, 6H, 8H) and by the basal endite of first maxilliped overreaching distal end of exopod (Fig. 14F) (vs. failing to reach or reaching distal end in Atyaephyra orientalis, Atyaephyra stankoi and Atyaephyra thyamisensis; Figs 4F, 6F, 8F). Atyaephyra tuerkayi sp. n. can be separated from Atyaephyra strymonensis by the presence of 1–3 post orbital rostral teeth (Fig. 13A) (vs. no post orbital teeth present leaving short unarmed proximal gap in Atyaephyra strymonensis; Fig. 9A) and by the endite of maxilla being 1.58–1.59 × as long as basal lower endite (Fig. 14G) (vs 1.77–1.95 in Atyaephyra strymonensis; Fig. 10G).