Primno latreillei Stebbing, 1888

Kim, Kyung-Won, Choi, Jae-Hong, Shin, So-Yeon & Kim, June Kim and Young-Hyo, 2024, Amphipod (Crustacea: Malacostraca) fauna of the continental shelf region in the Southern Sea of Korea, Journal of Species Research 13 (2), pp. 159-177 : 169-174

23. Primno latreillei Stebbing, 1888

ŵêēHƞăNjẹ (ṳạ)* ( Figs. 10, 13H)

Primno latreillei Stebbing, 1888: 1445 , pl. 179A; Bowman, 1978: 13, Fig. 9.

Material examined. 2♀♀, Site 6, 17 August 2022.

Description. Female (MABIK CR00254536): Body ( Figs. 10A, 13H) slender, 5.0 mm long: Head ( Fig. 10A) longer than pereonites 1 and 2 combined; rostrum short,

pointed; eyes covered almost part of head.

Gnathopod 1 ( Fig. 10B), basis subrectangular, elongate, with 1 setule on anterior margin; merus short, length subequal to width, with 1 setule on posterior margin; propodus elongate, narrowing distally, with 17 setules on anterior margin; dactylus falcate.

Gnathopod 2 ( Fig. 10C), coxa trapezoidal, expended anterodistally; basis elongate-ovate, posterior margin slightly curved, about twice as long as broad; carpus subrectangular; propodus slender, narrowing distally, with 2 setules on anterior margin; dactylus falcate; length ratio of articles 2 - 7 = 1.00: 0.18: 0.06: 0.32: 0.50: 0.12.

Pereopod 3 ( Fig. 10D), basis slender, elongate, width 0.2 times length, unarmed; merus subrectangular, with 2 teeth on posterior margin; carpus subrectangular, with 2 teeth on posterior margin; propodus slender, elongate; dactylus elongate; length ratio of articles 2 - 7 = 1.00: 0.18: 0.33: 0.48: 0.52: 0.22.

Pereopod 4 similar to pereopod 3, but slightly more elongated.

Pereopod 5 ( Fig. 10E), basis moderate, width about 0.5 times length, anterodistal margin with serration, produced posterodistally; merus with a large triangular process midanteriorly; carpus characteristic in form, with 14 teeth on anterior margin, proximal, fourth, seventh, and eleventh teeth elongate, length of elongate teeth subequal to width of carpus; propodus slender, elongate, subequal to carpus; dactylus falcate; length ratio of articles 2 - 7 = 1.00: 0.20: 0.45: 1.11: 1.07: 0.35.

Pereopod 6 ( Fig. 10F), basis moderate, convex midanteriorly, width 0.5 times length; merus with 2 teeth on anterior margin and 1 large tooth on posterodistal margin; carpus subrectangular, with 2 teeth on anterior margin and 1 tooth on posterodistal margin; propodus slender, elongate, unarmed; length ratio of articles 2 - 7 = 1.00: 0.23: 0.32: 0.51: 0.68: 0.22.

Pereopod 7 ( Fig. 10G), basis elongate-ovate, concave midanteriorly, elongate, about 1.5 times to the following articles combined; ischium to dactylus reduced, unarmed; length ratio of articles 2 - 7 = 1.00: 0.12: 0.11: 0.15: 0.23: 0.11.

Uropod 1 ( Fig. 10H) laterally serrulate, slightly longer than uropod 2.

Uropod 2 ( Fig. 10H) with 5 serrations laterally, subequal to uropod 3.

Uropod 3 ( Fig. 10H), subrectangular, serrulate, notched apically.

Telson ( Fig. 10H) small, subtriangular, unarmed.

Distribution. Korea (Jejudo Island, south and east coasts), Australia, Mexico, U.S.A.

Remarks. Primno latreillei Stebbing, 1888 is one of the smaller species within the genus Primno and is morphologically similar to P. johnsoni Bowman, 1978 . Primno johnsoni was considered a junior synonym of P. latreillei by Vinogradov et al. (1982) and Zeidler examined specimens among those identified as P. johnsoni in the Australia ( Zeidler, 1992; 1998). Within the morphological range of P. johnsoni, Zeidler synonymized the specimens with P. latreillei ( Zeidler, 2004) . Stebbing attached the most importance to the morphology of pereopods 5 and 7 in P. latreillei . These two species are morphologically similar in the following features: (1) pereopod 5 carpus, length of elongate teeth on anterior margin subequal to width of carpus; (2) pereopod 5 carpus, row of teeth on anterior margin with one of the elongate teeth proximally ( Bowman, 1978; Zeidler, 2004). However, P. latreillei is distinguished from P. johnsoni (different characters of P. johnsoni in brackets) by the following features: (1) gnathopod 1, propodus without robust seta (vs. with 2 robust setae medially), (2) pereopod 7, basis length more than 1.5 times length of following articles combined (vs. basis length about 1.2 times length of following articles combined), and (3) uropod 3 with well-developed apical notch (vs. without apical notch). Our Korean specimens are in good agreement with the description of Bowman (1978).