Coryphella cf. verta Ev. Marcus, 1970

Cetra, Nicolás & Roche, Andrea, 2023, Nudibranchia (Mollusca: Gastropoda) from San Matías Gulf, Northern Argentine Patagonia, Zootaxa 5244 (5), pp. 455-473 : 467

Coryphella cf. verta Ev. Marcus, 1970

( Figures 6E , 7B )

Material examined. Argentina, Río Negro : Plataforma , one specimen, 8 m, 21/02/2017 (ESCM-Ma-82); one specimen, 8 m, 01/02/2021 (ESCM-Ma-55); one specimen, 6 m, 17/08/2021 (ESCM-Ma-42).

Description. Length up to 10 mm, body translucent white. A longitudinal dorsal thin white line runs from the oral tentacles to the posterior end of the foot. Conical rhinophores with fine wrinkles and white tip. Cerata cylindrical, bright orange-red with white tips. Cerata grouped in widely spaced clusters along the dorsum. The anterior group begins just behind the rhinophores and contains 8 to 11 cerata, arranged in rows with no more than four per row. There are four to six posterior groups on each side of the body with a decreasing number of cerata in each group, up to 11 in the former, as few as one in the posterior one. Oral tentacles thin, elongated and slightly flattened ( Figure 6E ). Radular formula is 21 x 1.1.1 (ESCM-Ma-82). Rachidian teeth with a narrow central cusp, slightly longer than the 5-8 denticles on each side. Lateral teeth with a broad base and 5-7 long denticles ( Figure 7B ).

Geographic distribution and depth range. Recorded from Florida, Gulf of Mexico, Venezuela to southeastern Brazil ( Millen & Hamann 2006). Found on rocky bottoms between four and 12 m depth. Here extended to San Matías gulf, Argentina.

Biology. Found on hard bottoms associated with hydrozoans.

Remarks. Coryphella verta is a tropical species distributed from Florida to Brazil (Millen & Hamman 2006) and is recorded here for the first time in the Argentine Sea. C. verta can be distinguished externally from Flabellina dushia because F. dushia has oral tentacles longer than rhinophores, shorter cerata grouped in arcs, a wider body and broad opaque white bands on the notum, sides, head, and distal parts of the rhinophores and oral tentacles. Internally the lateral teeth of F. dushia are more acute, the seminal receptacle is shorter and larger and has a conical penis with a pointed tip ( Millen & Hamann 2006). Another tropical species is F. dana , which can be easily distinguished because it has annulate rhinophores ( Millen & Hamann 2006). The identification here is provisional due to observed differences in the body color pattern.

Figures

FIGURE 6. (A) Berghia rissodominguezi, (B) egg mass of Berghia rissodominguezi, (C) Doto uva, (D) egg mass of Doto uva, (E) Coryphella cf. verta, (F) Tritonia odhneri.

FIGURE 7. Scanning electron micrographs. (A) Berghia rissodominguezi (ESCM-Ma-37): radular teeth; (B) Coryphella cf. verta (ESCM-Ma-82): radular teeth; (C-D) Doto uva (MLP-Ma 14657): (C) radular teeth, (D) detail of the central teeth; (E-F) Tritonia odhneri (ESCM-Ma-10): (E) radular teeth, (F) detail of the central and lateral teeth.