Berghia benteva, (Marcus, 1958)

Domínguez, Marta, Troncoso, Jesús S. & García, Francisco J., 2008, The family Aeolidiidae Gray, 1827 (Gastropoda Opisthobranchia) from Brazil, with a description of a new species belonging to the genus Berghia Trinchese, 1877, Zoological Journal of the Linnean Society 153 (2), pp. 349-368 : 352-354

BERGHIA BENTEVA ( MARCUS, 1958)

Baeolidia benteva Marcus, 1958: 65 , figs 105–111.

Material examined: Praia dos Ossos (Buzios, Rio de Janeiro), 21 March 1998, two specimens, 0-m depth, 18–19-mm long. Praia dos Ossos (Buzios, Rio de Janeiro), 26 March 1998 , one specimen, 0-m depth, 18-mm long. Praia de Armação (Buzios, Rio de Janeiro), 1 July 1999, one specimen, 0-m depth, 10-mm long.

External morphology: Whitish to cream body ( Fig. 1B–D ), and translucent oral tentacles with white tips. The rhinophores have the same colour as the body, and bear papillae on their posterior side. On top of the head, in front of the rhinophores, there is opaque white pigmentation. Behind the rhinophores the black eyes are visible through the skin. Between the eyes there is a white patch of rhomboidal shape ( Fig. 4A ). The zone of pericardium is covered with irregular white spots. In addition to these characters, the smallest specimen ( Fig. 1B ) has an opaque white line on the back, between the pericardium and the tail, and white dots on each side of the line. The cerata are arranged in 12–15 pairs of groups: four or five precardial and between eight and ten postcardial ( Fig. 4B ). The postcardial cerata are thicker than the precardial ones. This characteristic is most evident in the smallest specimen. The first cluster consists of numerous cerata, which are smaller than those of the remaining groups. The cerata are organized in horseshoe-shaped arches, very close. There are one or two cerata rows in the ends of each arch; the larger cerata are located on the central part of the body. The digestive gland within each cerata is brown and the cnidosac is pink–red. The genital opening is situated below the second or third precardial ceratal group, and the anus is located approximately to the right of the pericardium. There is a broad foot and a long translucent tail with a white longitudinal line.

Internal morphology: The radulae in one 18-mm-long specimen have the formula 16 ¥ 0. 1. 0; in a 19-mmlong specimen they have the formula 22 ¥ 0. 1. 0. The teeth are arched and bilobed, with a notch in the central part and 27–29 denticles on each side ( Fig. 3C, D ). The radular formula in one 10-mm-long specimen is 16 ¥ 0. 1. 0. In this specimen the oldest teeth have short broad central cusps ( Fig. 4C ), which diminish in size from the first to the fourth tooth, and disappear from the fifth tooth ( Fig. 4D ). The masticatory borders of the jaws are smooth.

Remarks: The specimens studied are similar to those described by Marcus (1958). Unfortunately, his preserved material was faded at the time of the description, and we do not know the coloration of the living animals, but these had other very similar characteristics to our specimens, and we consider that they are the same species. Both have rhinophores with papillae on the posterior side, the cerata are arranged in up to 12 groups on each side of dorsum, and the masticatory border of the jaws is smooth. Furthermore, the teeth are bi-arched, and the central denticle is absent, except in the oldest teeth. This is the first record of B. benteva since its original description in 1958.

Distribution: Near Ubatuba, São Paulo ( Marcus, 1958); Praia dos Ossos (Buzios, Rio de Janeiro) (present paper).

Figures

Figure 1. Living animals. A, Anteaeolidiella indica from Praia dos Ossos. B, Berghia benteva from Praia de Armação (10-mm-long specimen). C, D, Berghia benteva from Praia dos Ossos (18- and 19-mm-long specimens). E, Berghia creutzbergi from Praia de Armação (13-mm-long specimen). F, Berghia marcusi sp. nov., from Praia de Armação (dorsal view, 12-mm-long specimen). G, Berghia marcusi sp. nov. (ventral view of the same specimen). H–J, Spurilla neapolitana from Praia de Armação. K, Spurilla neapolitana from Praia dos Ossos.

Figure 3. SEM images of radulae and jaws. A, radula of Anteaeolidiella indica from Praia dos Ossos; scale bar = 10 Mm. B, jaw of A. indica; scale bar = 100 Mm. C, radula of Berghia benteva from Praia dos Ossos (18-mm-long specimen); scale bar = 50 Mm. D, central part of the tooth of B. benteva; scale bar = 10 Mm. E, detail of the tooth of Berghia creutzbergi from Praia de Armação (13-mm-long specimen); scale bar = 10 Mm. F, jaw of B. creutzbergi (13-mm-long specimen); scale bar = 200 Mm.

Figure 4. Berghia benteva. A, dorsal view of the external morphology; scale bar = 5 mm. B, lateral view of a specimen, showing the arrangement of the cerata; scale bar = 5 mm. C, D, radular teeth (10-mm-long specimen, from Praia de Armação); scale bars = 100 Mm.