Coriollianassa maputo, Poore, 2023

Poore, Gary C. B., 2023, New records, one new genus and 21 new species of Callianassidae (Crustacea, Axiidea) from the Indo-West Pacific, Memoirs of Museum Victoria 82, pp. 167-255 : 192

Coriollianassa maputo sp. nov.

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42CC-841E-1B7BC2DA693A

Figure 18

Coriollianassa MOZ-31.— Robles et al., 2020: figs 1, 3, 6.

Material examined. Holotype. Mozambique, off Maputo, 25° 59' S, 34° 35'E, 638 m (MAINBAZA stn CC3172 ), MNHN IU-2014-10472 * (female, 3.9 mm, without chelipeds, pereopod 3).

Diagnosis. Rostrum carinate dorsally, with ventral keel-like carina. Maxilliped 3 merus truncate distally, with sharply rounded mesiodistal angle. Pleomere 1 tergite with dome-like posterior section. Telson trapezoidal, 0.8 times as long as wide.

Description of female holotype. Rostrum laterally compressed, deep, situated well below upper level of carapace, exceeding eyestalks, with sharp dorsal carina, with ventral convex keel-like carina. Carapace convex anteriorly in lateral view, as long as pleomeres 1–3 combined; orbital margin oblique-transverse; anterolateral angle scarcely produced, rounded; subanterolateral margin straight, anterior margin of branchiostegite set well back, almost vertical; cervical groove across 0.8 length of carapace, almost reaching linea thalassinica. Pleomere 1 tergite waisted in dorsal view, with deep saddle visible in lateral view; posterior section domed in lateral view. Pleomere 2 widest, wider than long, laterally flared. Pleomeres 3–5 each wider than long; pleura each with patch of plumose setae. Pleomere 6 1.25 times as long as wide, 1.3 times as long as pleomere 5, with slight ventrolateral projection.

Eyestalk 0.7 long as wide, with transverse distal margin bearing convex protruding cornea, well short of distal margin of antennular peduncle article 1. Cornea dome-shaped, well pigmented.

Antennular peduncle reaching to about distal margin of antennal peduncle article 4; article 1 clearly visible in dorsal view; article 2 shorter than article 1; article 3 as long as articles 1 and 2 combined; articles 2 and 3 with longitudinal ventral row of sparse long setae. Antennal peduncle article 5 0.6 length of article 4; scaphocerite with bifid apex.

Mandible molar process shelf-like, with small mesial tooth; incisor process with obsolete teeth. Maxilliped 3 ischium tapering, 2.2 times as long as wide, crista dentata comprising row of about 15 strong, irregular, erect spines, stronger distally, overlapping distal margin; merus about 0.6 times as long as ischium measured along outer margin, about 0.6 as wide as long, widest distally, with distinct transverse distal margin; carpus shorter than merus; propodus ovoid, 1.7 times as long as wide; dactylus digitiform, 0.75 times as long as propodus.

Pereopods 1 (chelipeds) missing.

Pereopod 2 merus lower margin slightly sinusoidal, 4.0 times as long as wide; carpus about 1.8 times as long as wide; chela subtriangular; palm about 0.17 times width of upper margin; dactylus 2.7 times as long as palm upper margin. Pereopod 4 merus 1.4 times as long as ischium; carpus 0.65 length of merus; propodus as long as carpus, with dense grooming setae distally on lower margin, scattered stiff setae on outer surface, with spiniform seta parallel to dactylus; dactylus half as long as propodus. Pereopod 5 slender, with chela longer than carpus, slightly curving; dactylus longer than fixed finger.

Female pleopod 1 uniarticulate, with subdistal setae. Pleopod 2 biramous. Pleopods 3–5 biramous, rami narrow; appendix interna slender, rod-like, projecting well beyond mesial margin of endopod, bearing coupling hooks on apical margin.

Uropodal endopod and exopod overreaching posterior margin of telson. Endopod oval-tapering, about 1.7 times as long as wide; anterior margin slightly convex; anterodistal margin without spiniform setae; distal margin convex, with fringe of setae; posterior margin without stouter marginal setae; upper surface without spiniform setae. Exopod dilating to rounded distal margin, 1.7 times as long as wide, exceeding endopod by about one quarter length; anterior margin convex, setose; posterior margin with numerous slender setae, with about 12 blade-like setae, indistinguishably merged with distal margin; upper surface with 1 submarginal slender seta about one third along; dorsal plate curved, short, about one fifth exopod width, with row of about 12 stiff setae distinct from setal row of distal margin.

Telson trapezoidal, 0.8 times as long as wide, broadest at anterior 0.2, narrowing posteriorly; greatest width 1.6 times posterior width; dorsal surface with few medial setae anterior to midlength; posterolateral angle with 1 spiniform seta; posterior margin convex, without median tooth.

Etymology. For Maputo, a town in Mozambique close to the type locality (noun in apposition).

Distribution. Western Indian Ocean; 638 m (known only from type locality).

Remarks. Four features distinguish Coriollianassa maputo from C mainbazae , the other species from the Mozambique Channel: (1) the strongly domed posterior section of pleomere 1; (2) the square merus of maxilliped 3; (3) the short eyestalk with transverse distal margin; and (4) the relatively shorter telson. The square merus of maxilliped 3 resembles that figured for C. sibogae and the eyestalk could be interpreted as belonging to this species, but the rostrum is scarcely carinate, specifically mentioned by De Man (1905, 1925a), and the telson is relatively shorter than in his figure. Coriollianassa maputo is weakly separated from two other species in the molecular phylogeny of Robles et al. (2020).

Figures

Figure 18.Coriollianassa maputo sp. nov. Mozambique, MNHN IU-2014-10472, female, 3.9 mm: a, eyestalks, carapace, pleon, telson, left uropod; b, carapace, eyestalk, pleomeres 1, 2; c, d, anterior carapace, eyestalk, antennular, antennal peduncles (lateral, dorsal views); e, telson, left uropod; f, mandible; g, maxilliped 3; h, pereopod 2; i, pereopod 4; j, k, pereopod 5 with detail; l–n, pleopods 1–3. Scale bars = 1 mm.