Gnathia micheli Ortiz, Winfield & Varela, 2012, n. sp.
Creators: name: Ortiz, Manuel
name: Winfield, Ignacio
name: Varela, Carlos
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Arthropoda
Malacostraca
Isopoda
Gnathiidae
Gnathia
Gnathia micheli

description: Gnathia micheli n. sp.
(Figs 1–4)
Material examined. Holotype. Adult male, length 3.3 mm, (ANC07.1.3.009–Marine collections of the Acuario Nacional de Cuba), associated with filamentous algae at a depth of 20 m, from the Cayo Matias Blue Hole, SW Cuba, 22°07’06”N, 81°30’45”W, Carlos Varela coll., 18 July 2010.
Paratype. Adult male, length 2.8 mm; adult male, length 2.6 mm; praniza larva, all specimens deposited on ANC07.1.3.010–Acuario Nacional de Cuba, associated with filamentous algae at a depth of 20 m, from the Cayo Matias Blue Hole, SW Cuba, 22°07’06”N, 81°30’45”W, Carlos Varela coll., 18 July 2010.
Diagnosis. Cephalosome 1.25 times longer than wide, without posterior tubercle, dorsal notch wide and deep; mandible with 1 seta, blade with 11 teeth, inner and incisor lobes present; pylopod with 2 articles, basal article foliaceous with 3 long distal setae, distal article circular with 3 short subdistal setae; maxilliped with basal article foliaceous and subquadrate, subequal in length to other 4; pereonal segment 1 short, hardly visible; pleotelson with 2 teeth on each lateral margin.
Description. Body with cephalosome quadrate, half length of pereon, lateral margins convex; numerous very fine granules on cephalosome; pereonal segments 1–4 smooth, pereon 5 with one subterminal small tubercle on each side, pereon 6 bearing 2 small anterior tubercles, 1 at middle area and 1 posterior on each side. Eyes well developed, lateral and sessile, 0.25 length of cephalosome; frontal border transverse; mediofrontal process absent; inferior frontolateral process conical, half length of superior frontolateral process; superior frontolateral process conical with two setae on tip and one on basal inner side; lamina dentate not visible in dorsal view, with 9 teeth; external scissura shallow; supraocular lobe pronounced; ventral accessory supraocular lobe very small. Cephalosome with broad dorsal sulcus which is tapering backward, without posterior median tubercle at base of sulcus (Fig. 1 A–C, F).
Antenna 1 sparsely setose, article 3 elongate, flagellum of 6 articles (Fig. 1 E).
Antenna 2 longer than antenna 1; flagellum of antenna 2 of 8 articles (Fig. 1 F).
Mandible curved half length of cephalosome; incisor present; unarmed carina; slight mandibular incisor halfway alone; ventral dentate; blade on proximal half, without pseudoblade; (Fig. 1 C, D).
Maxilliped with 5 articles; external margins of articles 2–4 bearing long plumose setae; endite barely, reaching one third of article 3 (Fig. 2 B).
Pylopod 2-articulated, internal margin of article 1 convex and covered with long plumose setae; with one long lateral and one short distal areolae; inner margin concave, covered with very short setae; distal border concave with 3 subdistal setae; distal article 0.15 times of basal, rounded with 3 small distal setae (Fig. 2 A).
Pereon widest anteriorly, as wide as cephalosome. Pereonite 1 dorsally not reaching lateral margins; pereonites 2 and 3 subequal; pereonite 3 with posterolateral lobe; pereonite 4 with deep anterior constriction; pereonites 4–6 narrower than pereonite 3, as long as pereonites 2 and 3 combined; pereonite 6 posterolateral corner with 5 setae; pereonite 7 narrow overlapping pleon (Fig. 1 A).
Pereopod 2 article 2 narrow, anterior margin with 3 tubercles and 4 robust setae directed upward, posterior margin with 4 setae; article 3 with a long robust seta and a short subdistal seta on anterior margin; 4 short setae and 2 long setae on posterior margin; article 4 with one long and one short setae on anterior margin, 3 setae and one distal tubercle on posterior margin, article 5 with one distal seta on anterior margin and one tubercle and 4 robust setae on posterior margin, article 6 with 3 equidistant anterior setae, 4 robust setae, and 2 short and robust distal setae on posterior margin, article 7 with one posterior robust seta and 3 setae anterior to nail (Fig. 3 A).
Pereopod 3 article 2 wide, anterior margin with 8 tubercles and 5 setae, posterior margin with 8 very short setae and one long distal seta; article 3 with one long and one short seta on anterior margin, 8 short setae on posterior margin, distal half finely serrate; article 4 with one long seta on anterior margin, 7 tubercles and 3 setae on posterior margin; article 5 with 2 big tubercles among which there are 4 smaller ones, and 6 setae of different lengths; article 6 with 2 distal setae on anterodistal edge, 8 tubercles and one robust distal setae on posterior margin; article 7 with one long and one short seta (Fig. 3 B).
Pereopod 4 article 2 wide with 4 tubercles on posterior margin; article 3 with 2 long setae on anterior margin, 11 tubercles on posterior; article 4 with 5 tubercles and 5 setae on posterior margin; article 5 with one short seta on anterior margin and one big and 5 small tubercles on posterior; article 6 with 2 setae on anterior margin, and 7 tubercles, one robust intermediate seta and one distal seta on posterior; article 7 with one short and one long seta (Fig. 3 C).
Pereopod 5 article 2 narrow with 5 short and one long setae on anterior margin, 3 long and 2 short setae on posterior; article 3 with 2 setae on anterior margin, 5 setae on posterior serrate margin; article 4 with 3 subdistal tubercles, 2 distal setae on anterior margin, 2 setae on posterior; article 5 with 3 posterior robust setae and 3 long anterior setae on posterior margin; article 6 with 3 robust setae and one seta on anterior margin, a serrate margin on basal half of posterior margin, 3 setae on distal half; article 7 with 2 long robust posterior setae (Fig. 3 D).
Pereopod 6 article 2 narrow with 8 tubercles and 5 setae on anterior margin, 3 distal setae on posterior; article 3 with 3 setae on anterior margin, 2 setae on basal half and a serrate margin with 2 distal setae on posterior margin; article 4 with 3 distal setae on anterior margin and 3 on posterior; article 5 with one distal seta on anterior margin, a serrate margin on anterior half and 3 setae on distal half of posterior margin; article 6 with 4 setae on anterior margin, a serrate margin on basal half with 2 strong robust setae and 4 setae on distal margin; article 7 with 4 basal setae and 4 intermediate anterior setae (Fig. 4 A).
Pleopod 2 with 7 long and 2 short distal setae on exopod; 7 long and one short on endopod; appendix masculina wide, almost straight and 0.33 times length of endopod (Fig. 4 B).
Uropod outer ramus longer and wider than inner; with 5 plumose distal setae on exopod; 4 plumose distal setae on endopod (Fig. 2 C).
Pleotelson subtriangular, 2 teeth on each lateral margin, shorter than endopod of uropod (Fig. 2 D).
Etymology. This species is named in honor of our friend Michel Hendrickx, researcher of Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, for his extensive contributions to carcinology.
Remarks. Gnathia micheli n. sp. is closely related to G. beethoveni Paul and Menzies, 1971 and G. hemingwayi, Ortiz and Lalana, 1997. The new species may be separated from these species by the following characters: G. beethoveni and G. h e m i n g w a y i have four subequal frontolateral processes on the frontal margin of the cephalosome, while in G. micheli n. sp. the two internal processes are short and the external ones are longer. The ventral view of the cephalosome of G. micheli n. sp. bears 9 teeth on lamina dentata whereas in G. beethoveni and G. hemingwayi it has no teeth. The pylopod of G. beethoveni and G. h e m i n g w a y i has three articles, while Gnathia micheli n. sp. has two articles. In G. micheli n. sp., the pereonal segment 4 is long and narrow anteriorly, whereas in G. beethoveni and G. hemingwayi it is short. Gnathia micheli n. sp. has two robust setae on each lateral margin of the pleotelson, while G. beethoveni and G. hemingwayi have none.
description: Published as part of Ortiz, Manuel, Winfield, Ignacio & Varela, Carlos, 2012, First records of peracarid crustaceans from the Cayo Matias Ocean Blue Hole, SW Cuba, with the description of two new species, pp. 53-66 in Zootaxa 3505 on pages 54-59, DOI: 10.5281/zenodo.209816