Exiliphotis, Jung, Tae Won, Coleman, Charles Oliver & Yoon, Seong Myeong, 2019

Jung, Tae Won, Coleman, Charles Oliver & Yoon, Seong Myeong, 2019, Taxonomic study on the photid amphipods (Senticaudata, Corophiida, Photoidea, Photidae) from Korean waters, with descriptions of a new genus and seven new species, ZooKeys 886, pp. 1-59 : 1

Genus Exiliphotis gen. nov.

Type species.

Exiliphotis petila sp. nov. (original designation by monotypy)

Etymology.

The composite epithet of the generic name, Exiliphotis, is a combination of the Latin word exilis and the generic name of Photis. This name refers to slender and elongate pereopods 5-7 with a noticeably narrower basis than those of other photid species. Gender is feminine.

Diagnosis.

Antenna 1 peduncle 2nd article 2.0 × as long as 1st article; accessory flagellum uniarticulated, vestigial. Gnathopod 1 carpus broad, 2.0 × as long as wide, 0.8 × as long as basis, propodus as long and as wide as carpus, posterior margin more convex than anterior margin, free from carpal lobe proximally, palmar margin convex, not defined distinctively; dactylus elongate, 0.8 × as long as propodus. Gnathopod 2 subequal to gnathopod 1; carpus 0.7 × as long as basis and that of gnathopod 1; propodus as long as basis, 1.6 × as long as carpus, posterior margin convex, not free from carpal lobe proximally, palmar margin oblique, strongly bisinuated; dactylus 0.7 × as long as propodus, exceeding palm. Pereopod 5 coxa bilobed, as long and 1.5 × as wide as that of pereopod 4, anterior lobe 0.9 × as wide as basis; basis subovoid, 1.3 × as wide as that of pereopod 4, half as wide as long; merus and carpus not lobed. Pereopod 6 similar to pereopod 5 except for coxa. Pereopod 7 1.3 × as long as pereopod 6; basis subrectangular, as wide and 1.2 × as long as that of pereopod 6; merus slender, 0.8 × as long as basis, slightly lobed posteriodistally; carpus not lobate, 0.7 × as long as merus; propodus 1.9 × as long as carpus. Pleonal epimera 2 and 3 subrectangular, rounded ventrally. Uropod 1 peduncle without distoventral spine; both rami 0.6 × as long as peduncle, terminated by rounded apex bearing robust seta. Uropod 2 0.7 × as long as uropod 1; both rami 0.9 × as long as peduncle, terminated by rounded apex bearing robust seta. Uropod 3 0.7 × as long as uropod 2, inner ramus half as long as outer ramus, diminished distally; outer ramus as long as peduncle, biarticulated, 2nd article vestigial, with 2 elongate setae subapically. Telson trapezoidal in dorsal view, 2.1 × as wide as long, distal margin not acute, with 1 terminal spine on each side.

Remarks.

Exiliphotis gen. nov. is similar to Graciliphotis Myers, 2009 in having relatively short coxae, which differs from those of other photids ( Myers 2009). However, Exiliphotis gen. nov. notably differs from Graciliphotis by the following differences: gnathopods 1 and 2 carpal lobes are slightly shorter and stouter; pereopods 5-7 are almost linear and elongate, particularly their basis are narrowly expanded; uropods 1 and 2 rami are terminated by the rounded apex bearing one small robust seta; uropod 3 is about half as long as in Graciliphotis , 0.7 times as long as uropod 2; uropod 3 outer ramus is biarticulated (uniarticulated in Graciliphotis ); and uropod 3 inner ramus is half as long as the outer ramus, while it is vestigial in Graciliphotis ( Myers 2009).