Quadrivisio chilikensis, Bhoi & Myers & Tarafdar & Smita & Jena & Patro, 2023

Bhoi, Gitanjali, Myers, Alan A., Tarafdar, Lipika, Smita, Moili, Jena, Ajay Kumar & Patro, Shesdev, 2023, A new species of the amphipod genus Quadrivisio (Senticaudata, Maeridae) from Chilika Lagoon, India, Zootaxa 5256 (1), pp. 36-42 : 37-40

Quadrivisio chilikensis sp. nov. Bhoi, Myers & Patro

Type Material: Female holotype. 9.5mm ( ZSI / EBRC /Cr14097),near Nalabana island (19°41'30.69"N, 85°17'53.2"E), from Chaetomorpha sp. , 18/08/2021, Coll. Gitanjali Bhoi, Lipika Tarafdar and M. Smita.

Paratypes. ZSI / EBRC /Cr14099, 1 female, 9.5 mm , ZSI / EBRC /Cr14100, 1 female, 9 mm & ZSI / EBRC / Cr14101, 1 female, 8.5 mm, same data as holotype .

ZSI / EBRC /Cr14098 (Slides of body parts) 1 male, 9 mm, same data as holotype .

Etymology: The species is named after the lagoon Chilika from which the type specimens were collected.

Diagnosis. Pleonites and urosome with carina.Antenna 1 primary flagellum with more than 40 articles.Antenna 2 flagellum twice the length of peduncular article 5. Pereopods 6 and 7 equal in length. Epimeron 3 hind margin smooth.Telson inner margin without setae, outer margin with one pair of plumose setae medially.

Description. Based on male paratype, 9.5 mm

Head. Cephalic lobe broad. Eyes divided into two parts. Antenna 1 peduncle much shorter than flagellum; first and second peduncular articles subequal; third peduncular article about one sixth length of second; primary flagellum composed of more than 40 articles; accessory flagellum with six articles reaching beyond the 10 th article of the primary flagellum. Antenna 2 peduncular articles 4 and 5 subequal in length; flagellum twice length of peduncular article 5 with 20-25 articles.

Mandible with 6 spines in spine row; molar process prominent; mandible palp article 1 two thirds length of article 2, without setae; article 3 longer than article 2, with 2 terminal setae. Maxilla 1 inner plate very broad withdistal plumose setae; outer plate with 9 apical robust setae; palp with 6-7 robust setae and few fine setae. Maxilla 2 inner plate, inner margin with double row of setae; outer plate with double row of terminal setae. Maxilliped inner plate reaching middle of outer plate; inner plate with 3 terminal robust setae and a row of fine setae; palp article 3 subequal in length with article 2.

Pereon. Gnathopod 1 slender; basis stout, subequal in length with coxa; carpus and propodus subequal in length; propodus subrectangular, slightly narrowing distally, anterior proximal and posterior distal margin with transverse rows of robust setae, palm convex; dactylus fitting palm, very stout basally and very slender apically.

Gnathopod 2 basis longer than propodus; basis short, cup-shaped; propodus pyriform, widest proximally, posterior margin with groups of robust setae, palm very oblique, defined by 2 robust setae; dactylus stout, nearly straight and equalling length of palm.

Pereopod 3 subequal in length with pereopod 5. Pereopod 4 shorter than pereopod 3. Pereopod 5-7 basis expanded, distal margin with robust setae and hind margins serrated. Pereopods 6 and 7 equal in length.

Pleon. Carina present on pleon and urosome. Epimera 1-3 with a dorso-lateral spine on each side. Uropod 1 peduncle longer than rami; endopod slightly longer than exopod. Uropod 2 peduncle about equal in length to endopod which is longer than exopod. Uropod 3 peduncle reaching to end of endopod of uropod 2; exopod subequal with endopod, thin leaf-like in structure, with short marginal setae; rami 3 times length of peduncle.

Telson reaching to end of peduncle of uropod 3, deeply cleft with 3-4 terminal robust setae; outer margin with a pair of plumose setae, inner margin without setae.

Female holotype. Female with sexually dimorphic characters. Gnathopod 2 smaller than that of male; propodus narrower, palm much shorter and less oblique; dactylus overlapping palm. Rami of uropod 3 a little smaller than those of the male. Rest of the characters are similar to the male.