Gammarus sezgini Baytaşoğlu, Aksu & Özbek, 2024, sp. nov.
Makaleler > Tam Makale · 2024
Yazarlar: Baytaşoğlu, Hazel, Aksu, İsmail, Murat ÖZBEK
Zenodo (CERN European Organization for Nuclear Research), Uluslararası, 2024
Özet
Gammarus sezgini sp. nov. Figs 2, 3, 4, 5, 6, 7 Material examined. Holotype: Türki̇y • Male; 9.8 mm; Rize Province, Yeşildere stream / Balat stream / Taşlı Stream; coordinates: 40.9493 ° N, 40.5394 ° E / 41.0227 ° N, 40.7130 ° E / 40.8701 ° N, 40.5859 ° E. Specimens collected by Hazel BAYTAŞOĞLU; 16 October 2019 and 1 September 2020. Holotypes with paratypes are stored under catalog number RTEÜ-FFR 200001; (GenBank accession numbers: PP 457383, PP 457384 for COI, and PP 456726, PP 456727 for 28 S; PP 457381, PP 457382 for COI, and PP 456724, PP 456725 for 28 S; PP 457385 for COI and PP 456728 for 28 S). Paratypes: 38 males and 34 females, same data as the holotype. Genetic material. RTEÜ-FFR-DNA K 2, K 4, Yeşildere stream, Rize Province, Türkiye, 40.9493 ° N, 40.5394 ° E (GenBank accession numbers: PP 457383, PP 457384 for COI, and PP 456726, PP 456727 for 28 S) - RTEÜ-FFR-DNA K 5, K 8, Balat stream, Rize Province, Türkiye, 41.0227 ° N, 40.7130 ° E (GenBank accession numbers: PP 457381, PP 457382 for COI, and PP 456724, PP 456725 for 28 S) - RTEÜ-FFR-DNA K 9, Taşlı stream, Rize Province, Türkiye, 40.8701 ° N, 40.5859 ° E (GenBank accession numbers: PP 457385 for COI and PP 456728 for 28 S). Diagnosis. A medium-large species. The body is yellowish; no dorsal keel or hump; the eyes are well developed; kidney-shaped; the extremities are not elongated; the second antenna bears numerous groups of long setae on the peduncle and flagellar segments; the antennal gland cone is straight and reaches to the distal end of the third peduncular segment; posterior margin of pereopod 3 densely setose; the setae on the posterior edge of pereopod 4 are shorter and fewer in number; the anterior margins of pereopods 5 to 7 bear spines in the male, while they bear long setae along with the spines in females; epimeral plates are pointed; the inner ramus of uropod 3 is slightly longer than 0.8 of the outer one; each telson lobe bears a pair of spines distally and setae longer than the spines. Description of male holotype. Head: Rostrum absent, inferior antennal sinus deep, rounded. Eyes kidney-shaped; length is slightly shorter than the diameter of the first peduncular segment of antenna 1 (Fig. 2). Antennae: Antenna 1 (Fig. 4 A) is half as long as the body length; the length ratio of the peduncular segments is 1: 0.75: 0.38; peduncle segments bear a few groups of minute setae; the length of the setae is much shorter than the segment where they are implanted; the main flagellum with 32 segments; each segment bears a few short setae in distal side; aesthetasc absent; accessory flagellum with five segments. Antenna 2 (Fig. 4 B) is shorter than antenna 1 (ratio 1: 0.7); the antennal gland cone is straight and reaches the distal end of the third peduncular segment; setation is rich both on peduncular and flagellar segments; peduncular segments 4 and 5 bear many groups of setae; the setae on the ventral part of the peduncle segments are shorter than the diameter of the segment but longer than those on the dorsal part; flagellum consists of 12 segments; flagellar segments are setose and swollen; each segment bears many long setae groups on both dorsal and ventral sides; calceoli absent. Mouthparts: Upper lip (Fig. 3 B) with numerous minute setules in the distal part. Left mandible (Fig. 3 F) with 4 - toothed incisor, lacinia mobilis with 4 dentitions, molar triturative. The first article of palp without setae; the second one bears 14 setae; the setae become shorter from distal to proximal. The third segment has 33 D-setae, 4–5 E-setae, one group of A-setae, and one group of B-setae. C-setae absent. Right mandible (Fig. 3 E) has a 4 - toothed incisor and bifurcate lacinia mobilis. Right maxilla 1 (Fig. 3 H, H ’) is asymmetric to the left; it has 16 plumose setae along the inner margin of the inner lobe. The outer lobe bears 11 distal stout serrate spines and some tiny setules on the inner margin. Palp of the outer lobe with no setae in the first segment and six stout spines (one of them lost) and three setae (two of them robust) on the distal part of the second segment, in addition to a marginal seta along the outer margin. The second article of left palp is elongated and bears 10 spines, five simple setae on its distal part, and no setae along the outer margin (Fig. 3 G, G ’). Lower lip (Fig. 3 A) has no inner lobe and bears numerous small simple setae along the distal margins of both lobes. Maxilla 2 (Fig. 3 C) has 20–30 simple setae in the distal part of the outer lobe and a few tiny hairs along the outer margin. The inner lobe also has 10–15 simple setae in the distal part in addition to 14–15 (two of them lost) plumose setae located in a diagonal row along the inner margin. There are also a few tiny hairs on the proximal part of the inner margin of the lobe. Maxilliped (Fig. 3 D) inner plate has three tooth-like spines and a spine in the distal part and the distal corner, respectively. Additionally, there are 10 plumose setae along the inner margin of the lobe. Outer plate armed with 5–6 serrate stout setae in the distal part and 12 spines along its inner margin. Coxal plates: Coxal plate 1 (Fig. 4 C) is rectangular, the distal part slightly widened, the ventral margin slightly convex, and bears four antero-distal setae and two postero-distal setae. Coxal plate 2 (Fig. 4 D) is in the shape of an elongated rectangle; distal part narrower than the proximal; the ventral margin is highly convex; anterodistal part with five setae; and postero-distal part with one seta. Coxal plate 3 (Fig. 5 A) is similar to coxal plate 2 in shape, with four and two setae in the antero- and postero-distal ends, respectively. The ventral edge of the coxal plate 4 (Fig. 5 B) is slightly convex and bears three and eight setae along the anteroventral and posterior margins, respectively. Coxal plate 5 (Fig. 5 C) bilobate and has one and five setae in the anterior and posterior lobes, respectively. Coxal plate 6 (Fig. 5 D) bilobate and has one seta in the posterior lobe. Coxal plate 7 (Fig. 5 E) is characterized by the presence of four setae on the postero-ventral margin. Gnathopods: Basal segment of gnathopod 1 (Fig. 4 C, C ’) bears many long setae along both margins; the length of the setae can be longer than twice the diameter of the segment. Ischium bears a group of setae in postero-ventral corner. Merus is in diamond shape and bears some setae along its disto-posterior margin. Carpus is triangular and bears two groups of setae along the anterior margin, in addition to many setae groups on both ventral and posterior sides. Propodus pyriform, the length / width ratio is 1: 0.60; anterior margin with four groups of setae; medial palmar spine is present; posterodistal corner armed with two strong spines in addition to some small spines; posterior margin bears 4–5 groups of setae. Dactylus reaches the postero-distal corner and bears a simple seta along the outer margin in addition to a small setule around the distal part of the inner margin. The basis and ischium of gnathopod 2 (Fig. 4 D, D ’) are similar to those of gnathopod 1 but have denser setae. Merus and carpus are more setose than those of gnathopod 1. Carpus is triangular, densely setose along the posterior margin, in addition to two groups of setae along the anterior margin. Propodus is densely setose and has a sub-rectangular shape; the length / width ratio is 1: 0.6; anterior margin bears six groups of setae; posterior margin with many groups of setae; medial palmar spine is present; the postero-distal corner is armed with six strong spines. Dactylus reaches the postero-distal corner and bears a simple seta along the outer margin in addition to a small setule around the distal part of the inner margin. Pereopods: Anterior and posterior margins of the basal segment of pereopod 3 bear long setae; the setae along the posterior margin are longer than those in the anterior margin; posterior margins of the merus, carpus, and propodus bear long setae; the setae can be more than three times the diameter of the segment where they are implanted. Dactylus slim, a minute plumose seta occurs on the outer margin; the inner margin with two small setules (Fig. 5 A). The basal segment of pereopod 4 (Fig. 5 B) has a similar setation to that of pereopod 3. Ischium, merus, carpus, and propodus have groups of setae along their posterior margins, but they are much shorter and less than those in pereopod 3. The length of the setae can be as long as (or slightly longer) than the diameter of the segment where they are implanted. Dactylus slim, a minute plumose seta, occurs on the outer margin; the inner margin with two small setules. Posterior margins of the basal segments of pereopods 5 to 7 (Fig. 5 C – E) are more or less convex and bear many short setae, anterior margins with 3–7 small spines, and no setae present on the inner surfaces of the basal segments; no spine exists in the postero-ventral corner of the basal segment of pereopod 7. Pereopod 7 bears no setae along the anterior margins of merus and carpus, while pereopods 5 and 6 have a few setae accompanying spines along with the mentioned segments. Propodus of pereopods 5 to 7 with 2–3 groups of long setae groups along their outer margins in addition to 5–6 groups of small spines along their inner margins. Dactylus slim, a minute plumose seta, occurs on the outer margin; the inner margin with two small setules. Epimeral plates: They are slightly pointed. Epimeral plate 1 (Fig. 6 C) bears 10 long setae along the anteroventral margin, and the postero-ventral corner is angular. Epimeral plate 2 (Fig. 6 B) bears five setae in the anteroventral corner; the ventral margin is armed with two spines; the posterior margin with 4–5 setules; the postero-ventral corner is pointed. Epimeral plate 3 (Fig. 6 A) is pointed; the anteroventral corner bears two setae; the ventral margin is armed with three spines in addition to a seta; the posterior margin bears 5–6 setules. Urosomites