Synapseudes marinae Balcu 2025, sp. nov.

Synapseudes marinae Bâlcu sp. nov. Figs 1, 5, 6, 7, 8, 9, 10, Tables 1, 2, 3 Material examined. Holotype • 1 ovigerous female with four eggs in marsupium, length about 1.6 mm (No. 250671). Paratypes • 1 female with oostegites, length about 1.8 mm (No. 250672); 1 female with empty marsupium, destroyed for DNA sequencing; 1 non-ovigerous female, dissected (permanent slide); from Greece, Sea of Crete, north of Crete Island, Bay of Malia, Milatos Beach, 35°19.22'N, 25°34.37'E, depth 0.4–0.5 m; from algae on rocks, rocky bottom; 23 October 2023; leg. Dr. Oana Paula Popa and Dr. Andrei Ștefan. Topotypes • 7 females (3 females with oostegites, 2 ovigerous females, 1 non-ovigerous female, 1 female with empty marsupium) and 2 manca I (No. 250673): 3 females destroyed (1 with oostegites, dissected, temporary slide; 1 with oostegites; 1 ovigerous for DNA sequencing); same collection data as holotype and paratypes; 18 June 2024; leg. Maxim-Jean Bâlcu, Dr. Oana Paula Popa and Dr. Andrei Ștefan. Other material. • 5 females (2 females with oostegites, 2 females with empty marsupium, 1 ovigerous) and 12 manca I (No. 250674): 1 manca I and 1 female with oostegites dissected for SEM analyses; 2 females with empty marsupium destroyed for DNA sequencing; from Greece, Sea of Crete, north of Crete Island, Bay of Malia, 35°19.54'N, 25°34.94'E, depth 0.5 m; from algae on rocks, rocky bottom; 18 June 2024; leg. Maxim-Jean Bâlcu • 2 females (1 female with oostegites, 1 female with empty marsupium) and 2 manca I (No. 250675): 1 female with empty marsupium used for SEM analyses; from Greece, Sea of Crete, north of Crete Island, near Xepapadeas Beach, 35°20.22'N, 25°44.96'E, depth 0.3–0.5 m; from algae on rocks, rocky bottom; 18 June 2024; leg. Maxim-Jean Bâlcu • 3 females (1 ovigerous female, 1 female with oostegites, 1 female with empty marsupium) and 11 manca I (No. 250676): 1 female with oostegites dissected for SEM analyses; 1 manca I destroyed for DNA sequencing; from Greece, Sea of Crete, north of Crete Island, near Xepapadeas Beach, 35°20.27'N, 25°44.94'E, depth 0.3–0.5 m; from algae on rocks, rocky bottom; 18 June 2024; leg. Maxim-Jean Bâlcu • 2 ovigerous females and 9 manca I (No. 250677): 1 manca I destroyed for DNA sequencing; from Greece, Mediterranean Sea, south of Crete Island, 35°1.2'N, 26°4.63'E, depth 0.5 m; from algae on rocks, sandy-rocky bottom; 19 June 2024; leg. Maxim-Jean Bâlcu • 1 ovigerous female and 3 manca I (No. 250678): 1 manca I destroyed for DNA sequencing; from Greece, Sea of Crete, Kalydon Island, 35°15.56'N, 25°45.27'E, depth 0.5 m; from algae on rocks, rocky bottom; 20 June 2024; leg. Maxim-Jean Bâlcu. Type locality. Greece, Sea of Crete, north of Crete Island, Bay of Malia, Milatos Beach, 35°19.22'N, 25°34.37'E. Diagnosis. Adult females body length 1.4–2.3 mm. Rostrum long and wide at base; anterior margin concave and rugose; with rows of scales. Pereonites 1–6 with one seta (apparently plumose) on each anterolateral corner. Pereonites 1–3 with one very small simple seta on each posterolateral corner. Pereonites 4–6 with three, two, and one setae, respectively, on each posterolateral corner. Pereonite 3 longest. Each pereonite much wider than long; rounded laterally. Pleonite 1 longer and wider than second. Pleotelson with mid row of 10 long apparently plumose setae and two small simple setae dorsally; one long apparently plumose and one small simple seta posterolaterally; two apparently plumose setae on apex caudo-dorsally. Antennule peduncle with four articles; articles 2 and 4 wider than long; first article longer than remaining articles combined; inner margin with two sharp thick and four rounded denticles. Inner flagellum with two articles; second article with three simple setae and one penicillate seta terminally. Outer flagellum with three articles; last article with four long simple setae and one penicillate seta terminally. Antenna peduncle with four articles; flagellum biarticulate, small, with four long thick setulate setae terminally. Maxilliped first palp article with one simple seta on inner side and one long thick bipinnate spine in outer distal corner. Article 2 largest; with six simple and four setulate setae on inner margin; one long thick bipinnate setiform spine on outer distal corner. Pereopod 1 basis with three or four dorsal apophyses; pereopods 2, 3 basis with one to three dorsal apophyses. Pereopod 1 propodus with three (rarely four) spines and one simple seta ventrally. Pereopods 2, 3 propodus with three (rarely four) spines. Pereopods 4–6 carpus with six, two, and one ventral spines, respectively. Pereopods 4–6 propodus with two small ventral spines. Description of non-ovigerous female (dissected paratype). Body (Figs 5 A, 7 A, B) short, relatively cylindrical, 4.8 times as long as wide; length about 1.5 mm. Cephalothorax (Figs 5 A, 7 A, B) (including rostrum) approximately 25 % of body length, about 1.3 times as long as wide. Rostrum (Figs 5 B, 8 D) long and wide at base, with anterior margin concave and rugose, and with rows of scales. Ocular lobes undefined; visual elements with dark pigment; one very small simple seta present under eyes. Carapace with two pairs of mid-dorsal simple setae, one medial simple seta on lateral sides, and two very small posterodorsal simple setae. Pereon (Figs 5 A, 7 A, B) approximately 61 % of body length, about 2.4 times as long as carapace length; each pereonite much wider than long and rounded laterally. Pereonite 3 longest, about 0.6 times as long as wide. All pereonites with one seta (apparently plumose) on each anterolateral corner. Pereonites 1–3 with three pairs of dorsal setae, the longest ones apparently plumose, and one very small simple seta on each posterolateral corner. Pereonite 4 with four pairs of dorsal setae, the longest ones apparently plumose; one apparently plumose seta and two very small simple setae on each posterolateral corner. Pereonites 5 and 6 with five pairs of dorsal setae, the longest ones apparently plumose; two simple setae and one simple seta, respectively, on each posterolateral corner. Pleon (Figs 5 A, 7 A, B) approximately 14 % of body length, consisting of two free pleonites and pleotelson. Pleonite 1 longer and wider than second, with one apparently plumose seta laterally and a row of nine apparently plumose setae dorsally. Pleonite 2 with a row of eight apparently plumose setae dorsally. Each pleonite expanded posterolaterally into a small spiniform process. Pleotelson (Figs 5 A, 7 A, B) about 1.6 times as long as combined length of pleonites, somewhat triangular; with acute apex in dorsal view, and crest-like in lateral view (Fig. 5 C), with a row of 10 long apparently plumose setae and two small simple setae dorsally; one long apparently plumose seta and one small simple seta posterolaterally; two apparently plumose setae on apex, caudo-dorsally. Antennule (Figs 5 D, 8 A, B). Peduncle with four articles; first article longest, about 1.6 times as long as wide; inner margin with six denticles (two mid-sharp thick and four rounded), two simple setae and some scales distally; outer margin with two penicillate, two long simple setae, and one setulate seta; four penicillate setae on ventral surface, subterminally; two penicillate and about three small setae on dorsal surface. Articles 2 and 4 wider than long. Article 2 about 0.4 times as long as article 1, with inner and outer distal dentiform prolongations; two small simple setae on inner margin, and three setulate setae and one simple seta on outer margin distally; five penicillate setae on ventral surface, terminally. Article 3 much narrower and about 0.9 times as long as article 2, with one simple and one setulate seta on inner margin and one simple seta on outer margin distally. Article 4 (common) 0.5 times as long as article 3, with two simple setae inner distally and a small notch for insertion of outer flagellum with one penicillate seta. Inner flagellum with two articles; first article with one simple and one penicillate seta inner distally; second article with two long thick simple setae, one small simple seta, and one penicillate seta terminally. Outer flagellum slightly longer than inner one, with three articles; first article with one aesthetasc and two simple setae on inner distal corner, two simple setae on outer corner; article 2 with two long simple setae and one aesthetasc; article 3 with four long simple setae and one penicillate seta terminally. In ventral view, common article 4 appears to consist of two parts and the peduncle of only three articles; outer flagellum with four articles; inner flagellum with three articles (Fig. 8 B). Antenna (Figs 5 E, 8 C) (without terminal setae) smaller than first peduncular article of antennule. Peduncle with four articles. First article wider than long, with an inner dentiform expansion bearing many hairs and some rows of scales. Articles 2 and 3 wider than long. Article 2 about 0.5 times as long as article 1, with rows of scales, two sharp denticles, and one small simple seta on inner margin, and one small simple seta on outer distal corner. Article 3 shortest, about 0.7 times as long as article 2; outer and inner margins slightly denticled, with one small simple seta on inner distal corner. Article 4 longer than articles 2 or 3, with inner and outer distal dentiform prolongations; one mid-inner and five terminal penicillate setae; one long setulate seta, subterminally. Flagellum biarticulate, small; first article naked; second article minute, with four long thick setulate setae, terminally. Squama absent. Labrum (Figs 5 F, 8 G) with many long setulae and with a conical projection, anteriorly directed. Mandibles (Figs 5 G, H, 8 H – K) with three-articled palp; article 1 about 2.7 times as long as wide, naked; article 2 about 2.5 times as long as wide, naked; article 3 smallest, with two unequal setulate setae, terminally. Pars molaris without distinctive features. Pars incisiva of left mandible (Fi