Cyathura odaliscae, Heard, Richard W. & Vargas, Rita, 2015

Cyathura odaliscae , new species

( Figs 1–4 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 )

Material examined.— Holotype: adult male, 5.1mm in length ( MZUCR 2327-03), Terraba River delta, Osa, Puntarenas (09°00.7'N; 83°61.12'W); Pacific coast of Costa Rica; oligohaline mangrove habitat; coll. R. Vargas; 4 August 2000.— Paratypes: 6 males, 44 females (4 ovigerous); MZUCR 2505-01, Terraba River delta, Osa, Puntarenas, mangrove habitat, coll. S. Echeverria, 10 October 2002. — 2 males, 4 pre-incubatory females, Terraba River delta, Osa, Puntarenas, mangrove habitat, coll. S. Echeverria, 10 October 2002 (collection of RWH). — 2 females, 1 ovigerous (MZUCR-2324-13), same collection data as for holotype. —Other material: 3 subadults, same collection data as for holotype.

Diagnosis. Body pigmented. Eyes distinct with 8–10 well-developed ommatidia and associated pigment. Antenna 1, male having flagellum with two apparent articles; first attenuated, about 0.6 length of peduncle article 3; article 2 minute, with cluster of numerous aesthetascs and 6–7 terminal setae, female with few (usually 3) aesthetascs. Mandible with lamina dentata bearing 8–10 (usually 9) relatively large, distally curved, saw-like spines. Maxilliped having reduced coxa with small, rounded epipod; basis broad (length about 1.4 that of width) and about as long as combined lengths of palp articles, lacking endite; palp with distal article suboval, wider than long. Pereopod 1 with 3–4 comb setae in both sexes near distal margin of upper inner face of propodus. Male copulatory stylet (appendix masculina) complex, inner subterminal margin armed with strong hook, outer subdistal margin with small, papilla-like lobe with surface having minute, short spinules. Uropodal exopod extending past distolateral margin of endopodal article 1, lacking distinct subdistal notch. Telson widest anteriorly, length about 1.8 times length, lateral margins straight, gradually tapering to rounded tip.

Description. Adult male: Length 4.0– 5.1 mm. Body (viewed dorsally) about 9 times longer than wide. Head pigmented, slightly more than half length of pereonite 1, with blunt subquadrate rostrum extending anteriorly to or just beyond eye lobes; eyes relatively large, pigmented with 7–9 (8) well-developed ommatidia.

Pereon. Pereonite 1 largest, about 1.3 times longer than pereonite 2; pereonites 2–6 about equal in length; pereonite 7 shorter than other pereonites.

Abdomen. Slightly longer than pereonite 6 and about 0.9 length of pereonite 5, widest posteriorly; urosomite about half length of fused pleonites 1–4.

Telson ( Fig. 1 View FIGURE 1 K). Linguiform, margins not concave, about 1.3 times length of abdomen widest anteriorly with posterior margin rounded, slightly less than twice as long as wide; lateral and posterior margins fringed with small setae, posterior margin with two pairs of larger setae (one lateral pair and one medial, longer, terminal pair); dorsal surface with some minute setae and pair of long simple, sublateral setae near posterior end; pair of statocysts evident, well-developed.

Antenna 1 ( Fig. 1 View FIGURE 1 E). Peduncle with 3 articles, first article widest, nearly 1.5 length of article 2, inflated laterally and partially overlapping inner anterior margin of eye lobe, lateral margin with 4 or more brush setae; article 2 cylindrical with 3 brush setae on distolateral margin; article 3 about equal in length to article 2 but narrower and attenuated, brush seta and simple setae on distolateral margin. Flagellum with two apparent articles; first attenuated, about 0.6 length of peduncle article 3; article 2 minute, with cluster of 6–7 terminal setae, numerous aesthetascs.

Antenna 2 ( Fig. 2 View FIGURE 2 A, B) with 6 articles; article 5 extending past tip (excluding terminal setae) tip of antenna 1. Dorsal aspect: Article 1 reduced, proximally concave; article 2 massive dorsally with deep, oblique groove for insertion of basal peduncular article of antennule, in margin with dense row of fine setae; article 3 short, wider than long; article 4 and 5 subequal in length; article 6 (=flagella article 1) short and blunt, width greater than length, terminating in dense cluster of setae, length less than 1/4 that of article 5.

Mandible ( Fig. 3 View FIGURE 3 A, B). Incisor having 3 narrow distal cusps; lamina dentata bearing 8–10 relatively large, distally curved, saw-teeth. Palp well-developed; article 1 short, barrel-shaped, appearing asetose; article 2 about twice as long as article 1, inner margin with dense row of short setae interspersed with 6 or 7 long setae (distal most seta with expanded base, much larger than others); article 3 equal in length to article 2, inner margin with about 15 setae of varying length, tip having 5 well-developed curved pectinate seta, distal most largest.

Maxilla 1 ( Fig. 3 View FIGURE 3 C, D) outer lobe styliform with 1 long terminal tooth (spine) and 5–6 smaller, closely set, subterminal teeth; inner lobe reduced, elongate, bearing single terminal seta.

Maxilliped ( Fig. 3 View FIGURE 3 E) composed of 4 articles; epipod relatively small, suboval. Article 1 small compressed. Article 2 laterally inflated, equal to combined length of articles 2 and 3; endite absent. Article 2 with few small lateral setae, inner margin fringed with small setae and 5 marginal or sub-marginal, larger simple setae, 3 large simple setae on surface of distal 1/3 of article. Article 3 slightly more than 1/3 length of article 2, suboval with some small marginal setae and cluster of 5 larger setae on inner subdistal margin. Epipod, suboval, not welldeveloped.

Pereopod 1 ( Fig. 3 View FIGURE 3 F–I). Subchelate, stout, strongly developed. Propodus with clasping margin bearing blunt tooth or tubercle, row of fine spinules (appearing pectinate); outer face with 7–8 simple marginal or sub-marginal setae, inner subdistal margin with four sub-marginal finely pectinate (comb) setae just proximal to articulation with dactylus. Dactylus with clasping margin finely setulate or pectinate with stout spiniform seta originating at junction with unguis ( Fig. 3 View FIGURE 3 F–G).

Pereopods 2–7 ( Fig. 4 View FIGURE 4 ). Propodus with stout, distally spatulate, spiniform seta on distoventral margin adjacent to articulation with dactylus; propodus as long or longer than combined lengths of carpus and merus; ischium about equal in length (pereopods 2 and 3) or slightly longer (pereopods 4–7) than propodus. Frontal carpal lobe on pereopods 6 and 7 more distally produced than on pereopods 2–5. Pereopods 6 with dactylus having small, stout, spiniform seta originating at junction with unguis ( Fig. 4 View FIGURE 4 E) and pereopod 7 with two such seta at junction with unguis ( Fig. 4 View FIGURE 4 F). Other setation as illustrated. Unguis on pereopods 2–7 less than half total length of dactylus.

Uropod ( Fig. 1 View FIGURE 1 J). Endopod with carina along inner margin of sympod (proximal article), distal article subovate, extending to posterior margin of telson, distal two thirds with numerous short marginal setae interspersed with 8–10 long simple setae. Exopod extending distally to, or just past, articulation of terminal endopodal article, rounded distally; lateral margin convex, crenulated, with row of 10–12 short plumose setae interspersed with small short setae, and pairs of longer simple setae medially and subdistally.

*Reduced to small, distally attenuated process with 1 or 2 small terminal setae

**Relatively well-developed, distally expanded with numerous small setae on surface (= “ carinata –like”).

Ovigerous female ( Fig. 1 View FIGURE 1 A–D, F, I): Length 5.1–5.5 mm, 7–8 times longer than wide. Similar to male, except antenna 1 larger, less attenuated, and lacking dense cluster of aesthetascs. Antenna 2 appearing similar to male, though not as setose. Pereopod 1 with inner subdistal margin having 2–4 (depending directly on increase in body size) finely setulate (comb) setae just proximal to articulation with dactylus, but not as long as in male. Pleopod 1 ( Fig. 1 View FIGURE 1 F) with 3 reticulae (coupling hooks) on inner distal margin of basis.

Etymology. This species is named in honor of Odalisca Breedy, Escuela de Biología and CIMAR (Centro de Investigación en Ciencia del Mar y Limnología), and CIEMIC (Centro de Investigación en Estructuras Microscopica), Universidad de Costa Rica, in recognition of her contributions to the study of the marine invertebrate fauna of Costa Rica.

Remarks. With the inclusion of C. odaliscae n. sp., there are now 32 recognized members of the genus Cyathura (see Schotte et al. 1995 —onwards; Table 1 View TABLE 1 ). Of these, males are now known for 22 species. Twelve of these, C. bentotae Müller, 1991 ; C. bruguiera Poore & Lew Ton, 1985 ; C. cubana Negoescu, 1979 ; C. esquivel Kensley, Ortiz, & Schotte, 1997 ; C. furcata Nunomura & Hagino, 2000 ; C. hakea Poore & Lew Ton, 1985 ; C. indica Barnard, 1925 ; C. munda Menzies, 1951 ; C. profunda Kensley, 1982 ; C. rudloei Kensley, 1980 ; C. shanghaiensis Liu, Poore, & Chen, 2013 ; C. terryae Müller, 1990 ), are distinguished from C. odaliscae by having relatively simple, unornamented male copulatory stylets (see Fig. 5 View FIGURE 5 A–L).

The males described for the remaining 10 species, C. burbancki Frankenberg, 1965 ; C. carinata ( Krøyer, 1847) (type species); C. higoensis Nunomura, 1977 ; C. kikuchii Nunomura, 1977 ; C. muromiensis Nunomura, 1974 ; C. madelinae Hackney & Ganucheau, 1989 ; C. odaliscae n. sp; C. polita ( Stimpson, 1856) ; C. sagamiensis Nunomura, 2006 and C. shinjikoensis Nunomura, 2001 , have complex or ornamented male stylets (see Fig. 5 View FIGURE 5 K–U). The male copulatory stylet of C. odaliscae n. sp., differs from these other species by having its inner subterminal margin armed with strong distally curled, hook-like process and the outer subdistal margin having small lobe with minute, short spinules ( Figs 1 View FIGURE 1 H, 5V). The males for the remaining nine species of the genus are undescribed (see Table 1 View TABLE 1 ).

Cyathura guaroensis Brusca & Iverson, 1985 View in CoL from Costa Rica and Cyathura munda View in CoL from Baja California are the only two species previously known from the eastern Pacific ( Menzies 1951; Brusca & Iverson 1985). They can be distinguished from C. odaliscae by the anterolateral margins of their telsons being slightly concave and widest in the mid-region; whereas, those of the new species are straight, being broadest in the region of fusion with pleonite. Besides its unique male stylet, C. odaliscae can also be distinguished from C. munda View in CoL , as well as C. francispori View in CoL , by the mandibular palp. The distal article of the palp of C. odaliscae is well-developed with a row of setae on the inner margin and five curved spiniform setae; whereas, on C. munda View in CoL , and C. francispori Negoescu, 1981 View in CoL , the distal article is greatly reduced with only a one or two distal seta. Cyathura munda View in CoL also differs from C. odaliscae by its pereon lacking pigmentation.

The other eastern Pacific species, Cyathura guaroensis View in CoL , appears atypical by lacking a distinct tooth on the grasping margin of the propodus, as well as, a distoventral lobe or process on the carpus; this condition, however, needs confirmation. Other differences between C. odaliscae and C. guaroensis View in CoL include differences in body pigmentation and setation of the maxilliped.

The female of C. odaliscae differs from those of the tropical, northwestern Atlantic species, C. cubana View in CoL and C. tridentata Wagner, 1990 View in CoL , by the absence of a maxillipedal endite. The female of C. odaliscae is further distinguished from that of C. tridentata Wagner, 1990 View in CoL by lacking a setose maxillipedal epipod. Besides its distinctive male stylet, the new species differs from the more temperate NW Atlantic species of C. politaburbancki-madelinae complex by its smaller adult size, the setation of the maxilliped, and morphology and setation of the pereopods. The new Costa Rican species is separated from the Japanese species C. omorii Nunomura, 1974 View in CoL by the shape of the first pereopod shape and the setation and/or dentition of the first maxilla. Cyathura odaliscae is separated from the Australian species, C. aegiceras Poore & Lew Ton, 1985 View in CoL by the maxilliped having a much smaller epipod and differences in the shape and distribution of the setae on the first article of the palp. Cyathura odaliscae differs from the somewhat similar C. peirates Bamber, 2008 View in CoL from Hong Kong, by its distinctly stouter body, less than 9 times the width for the former compared to over 12 times width for the latter. Further, articles 1 and 2 of the mandibular palp on C. odaliscae are densely setose. These palp articles are sparsely setose on both C. aegiceras View in CoL and C. peirates View in CoL ; as well as, on that of the Mediterranean species C. francispori View in CoL (see Negoescu 1981). The remaining four nominal species, C. eremophila Monod, 1925 View in CoL , C. estuaria Barnard, 1914 View in CoL , C. pusilla View in CoL , and C. truncata Dang, 1965 View in CoL (see Barnard 1925; Monod 1925; Stebbing 1904; Dang 1964, respectively), are too incompletely described and illustrated to warrant any meaningful comparison with C. odaliscae .

Ecological notes. Cyathura odaliscae appears to be adapted to low salinity conditions. The specimens used in this study were collected from decaying wood in mangrove habitat. It co-occurred with several other peracarid crustaceans, including three amphipods (i.e., Corophium panamanesis Shoemaker, 1949 ; Chelorchestia costaricana Stebbing, 1906 View in CoL ; and an apparently undescribed Leptocherius –like species), and an apseudomorphan tanaidacean tentatively identified as Discapseudes colombiensis Guţu and Ramos, 1991 View in CoL (see Heard et al. 2008).