Cymadusa makranica, Momtazi, 2022

Momtazi, Farzaneh, 2022, Ampithoidae (Crustacea: Amphipoda) from the Persian Gulf and the Gulf of Oman, Zootaxa 5159 (3), pp. 367-382 : 372-373

Cymadusa makranica sp. nov.

( Figures 5–6 )

Material examined. Holotype, 1 male, 10.8 mm ( INIOC2-14 S) intertidal zone, Djod , Gulf of Oman (25°27’0.00”N, 59°30’36.00”E), May 2015 . Paratype, 1 male, 10 mm ( ZUTC Amph. 2365), intertidal zone, Djod , Gulf of Oman (25°27’0.00”N, 59°30’36.00”E), May 2011 .

Type locality. Gulf of Oman

Diagnosis. Antenna 1 accessory flagellum with two article. Maxilla 1 inner plate with 4 long and three short slender setae. Coxa 1 not anteriorly round, gnathopod 1 with sparsely setose margins; merus produced to form a small, subacute distoventral lobe; carpus as long as propodus; palm acute, entire, with 1 defining robust seta. Gnathopod 2 palm defining with large tooth and small tooth in the middle that separated each other with cleft; dactylus shorter than palm. Epimeron 3 posteroventral corner rounded. Uropod 3 peduncle with 6 distal robust setae. Telson distally truncated, apical cusps small, with multi apical and medial slender setae.

Description. Based on holotype, male, 10.8 mm, INIOC2-14S.

Head. Head as long as deep; eyes poorly developed. Antenna 1, slightly longer than second antenna; peduncular article 1 subequal to article 2, second article longer than third one; flagellum with 42 articles; accessory flagellum 2–articulate. Antenna 2, peduncle without brush setae; fourth article longest; flagellum with 36 articles. Upper lip distally setose. Lower lip, outer plates notched forming a deep distal cleft. Mandible, molar well developed, triturating, accessory setal row with 7 serrate setae; palp 3–articulate, article 1 shorter than article 2; article 2 with 1 distal seta; article 3 the longest, with 9 apical and two marginal setae. Maxilla 1, inner plate with 4 distal and three proximal setae; outer plate with 9 dentate setae; palp well developed, two articulate, distal article apically with 10 short robust and 4 long setae. Maxilla 2, inner plate narrower than outer plate. Maxilliped, outer plate with row of large robust setae along medial margin, inner plate developed, not reach to end of first palp article, palp 4–articulate.

Pereon. Gnathopod 1; smaller than gnathopod 2; coxa 1 not anteriorly produced; basis longer than propodus, with 6 long proximal setae on the posterior margin, anterodistal lobe present with one seta; ischium small, trapezoidshaped with multi setae on the posterior margin; merus anterodistal lobe acute; carpus as long as propodus with one defining large robust seta; dactylus subequal in length to palm, inner margin crenate; propodus subquadrate, length 1.9 × width, palm acute. Gnathopod 2; coxa as long as deep; basis without anterodistal lobe, shorter than propodus, with 5 long proximal setae on the posterior margin; ischium trapezoid with one posterodistal seta; merus subrectangular, anterior margin naked; carpus as long as merus, shorter than propodus, subtriangular, with small posterodistal lobe, anterior margin with one seta; propodus 1.5 × width, subrectangular, anterior margin without seta, posterior margin straight, palm defining with large tooth and small tooth in the middle that separated each other with cleft; dactylus shorter than palm. Pereopod 3–4 similar, basis slightly expanded with multi long setae on both margins, ischium trapezoid; merus subequal to carpus; propodus with multi slender setae on the posterior margin. Pereopod 5, coxa with multi surface setae; basis expanded; merus slightly longer than carpus; carpus subquadrate; propodus subrectangular with four robust setae on posterior margin; dactylus strongly curved. Pereopod 6 similar to pereopod 7, slightly shorter than P7, basis slightly expanded with two posterodistal and three anterodistal robust setae; merus slightly longer than carpus; carpus subquadrate; propodus subrectangular with five robust setae on posterior margin; dactylus curved. Pereopod 7, basis slightly expanded with two posterodistal and three anterodistal robust setae; merus slightly longer than carpus; carpus subquadrate; propodus subrectangular with six robust setae on posterior margin; dactylus curved.

Pleon. Uropod 1; peduncle with nine robust setae, with large interannal spur, setal fringe absent; rami unequal, shorter than peduncle, outer ramus larger with 11 marginal robust setae and four apical setae; inner ramus with 13 marginal and four apical robust setae. Uropod 2, peduncle larger than outer ramus, with five robust setae, setal fringe absent; rami unequal, outer ramus shorter than inner ramus with eight marginal and three apical robust setae; inner ramus with nine marginal and five apical robust setae. Uropod 3, peduncle longer than broad; peduncle with six distal robust setae, inner ramus 0.6 × peduncle, with four apical and one marginal robust setae and some long simple setae; outer ramus with 2 apical large curved robust setae. Telson, trapezoid, apically truncated.

Female, unknown.

Etymology. The term “makranica” is referred to the ancient name of the type locality, the Gulf of Oman, Makran Sea.

Remarks. The genus Cymadusa Savigny, 1816 was described from the Egypt. Barnard and Karaman (1991) diagnose Cymadusa as having a 1–2-articulate accessory flagellum. Peart (2004; 2007) re-evaluated the genus and prepared a detailed description differentiating it from alliance genera based on the presence of 1–3 articulated accessory flagellum and the shape of third uropod. Cymadusa was known as the tropical genus ( Peart 2007) composing of 52 species (Horton et al., 2020). However, the assumption of being monophyletic was debunked by Peart and Ahyong (2016).

The new species Cymadusa makranica is clearly distinguishable from other species with unique shape of propodus of second male gnathopod, presence of two set of setae on inner plate of first maxilla, bearing two articulated accessory flagellum, the first gnathopod with carpus as long as propodus and less setae on the both antennae. This species could be characterized from other species of Cymadusa in the studied area with less setation in antennae, gnathopods and coxa1–4 and bearing first gnathopods with carpus as long as propodus. The new species is most similar to Cymadusa imbroglio Rabindranath, 1972 . However, C. makranica could be differentiated by two articulated accessory flagellum in the first antennae (one articulate in C. imbroglio ), 4+3 setae on inner plate of the first maxilla (5 setae in C. imbroglio ), the shape of propodus in the male gnathopod 2, presence of fewer setae on uropods, having longer third article than second one in the mandibular palp, and absence of protuberance on palm of first gnathopod.

In spite of multi sampling in Djod station, only 2 samples of C. makranica were found.

Figures

FIGURE 5. Cymadusa makranica sp. nov. male, 10.8 mm, (INIOC2–14S), Djod, Gulf of Oman.

FIGURE 6. Cymadusa makranica sp. nov. male, 10.8 mm, (INIOC2–14S), Djod, Gulf of Oman.