Roboastra, EUROPAEA GARCIA GOMEZ, 1985

Pola, M., Cervera, J. L & Gosliner, T. M., 2005, Review of the systematics of the genus Roboastra Bergh, 1877 (Nudibranchia, Polyceridae, Nembrothinae) with the description of a new species from the Galápagos Islands, Zoological Journal of the Linnean Society 144 (2), pp. 167-189 : 179-180

ROBOASTRA EUROPAEA GARCÍA GÓMEZ, 1985

( FIGS 3D , 4D , 6C , 7E )

Material examined: Torre, Marbella, Spain, July 1995, 1 specimen, 10 m depth, 30 mm, collected by J.L. González ( MNCN 15.05 /46612). Torre , Marbella , Spain, September 1995, 1 specimen, 10 m depth, 18 mm, collected by M. T. Barrea ( CASIZ 166049 ) . Torre, Marbella , Spain, August 1996, 2 specimens, 10.7 m depth, 15 & 19 mm, collected by K.L. Schick ( CASIZ 166053 ) . La Herradura, Granada, Spain, February 1993, 1 specimen, 12 m depth, 14 mm, collected by A. Barrajón and M. Zarauz ( MNCN 15.05 /29203). Arrecife La Cañonera, Strait of Gibraltar, Spain, June 2002, 1 specimen, 17 m depth, 50 mm, collected by Alma Sánchez ( MNCN 15.05 /46650). Funchal , Madeira, June 1999, 1 specimen, 100 m depth, 35 mm ( MMF 31021) . Ponta do Baleeira, Sagres, Portugal, July 2002, 1 specimen, 20 m depth, 14 mm, collected by M. Pola ( MNCN 15.05 /46613). Ponta do Baleeira , Sagres , Portugal, July 2002, 1 specimen, 20 m depth, 10 mm, collected by M.A. Malaquias ( MNCN 15.05 / 46613). Specimens were collected on rocks and were measured following preservation .

Distribution: This species is known mainly from the Strait of Gibraltar and southern Iberian Peninsula ( García Gómez, 1985, 2002; Cervera et al., 1988; García Gómez et al., 1989, 1991; Moreno & Templado, 1998; Schick, 1998; Megina, 2000; Ocaña et al., 2000; Sánchez-Tocino, Ocaña & García 2000; Grande et al., 2002; Megina & Cervera, 2003). One misidentified specimen of Plocamopherus from Madeira deposited at the Natural History Museum (London) (1863.9.19.3), supposedly collected by Rev. R. Lowe, was correctly identified as belonging to Roboastra , very probably R. europaea . This hypothesis has been strongly supported by the recent collection of one specimen (also photographed) of this species at Funchal harbour.

This species has been also recorded in southwestern Portugal (Calado et al., in press) and Catalonian coasts (north-eastern Iberian Peninsula, Mediterranean Sea) (Schick, pers. comm.). Poddubetskaia & Petit de Voice (2003) provide an illustration of R. europaea from Dakar ( Senegal). This is the southernmost record of this species in the Atlantic.

External and internal morphology: Described in detail and figured by Pola et al. (2003). Regarding the colour pattern, this species can exhibit two colour varieties ( Fig. 6C 1 , C 2 ). The radular formula of two 15- mm-long specimens (preserved) is 23 ¥ 4.1.1.1.4; that of the 30-mm-long specimen (preserved) is 25 ¥ 4.1.1.1.4 ( Fig. 7E ). The reproductive system is triaulic ( Figs 3D , 4D ). The hermaphroditic duct widens into a S-shaped ampulla that has thick walls. The bursa copulatrix is rounded and the seminal receptacle is elongate; both are similar in size. The seminal receptacle has a short duct that connects to the vagina, near the bursa. The deferent duct, which lacks a morphologically well-differentiated prostate, is long and coiled, ending in a dilated penial atrium. The vaginal gland is large with muscular walls, convex on one side and concave on the other. The penis is located within the distal end of this muscular portion and is armed with at least three different kinds of hooked and chitinous spines arranged in helicoidal rows. Anatomical descriptions are based on the illustrations by Pola et al. (2003).

Remarks: Roboastra europaea was described by García Gómez (1985) as the first species of the genus in the Atlantic Ocean, from the Strait of Gibraltar. Pola et al. (2003) redescribed the species and updated its geographical range to south-western Portugal (Calado et al., in press) and the Catalonian coast (north-eastern Spain).

The anatomy of this species and the reproductive system of the specimen examined (MNCN 15.05/ 46650) are very similar to those descriptions and no substantive differences have been found, except with regard to identification of the uterine duct, which was not reported before. The uterine duct is long and convoluted, going from the middle of the vagina to the oviduct. García Gómez (1985) mentioned the presence of a fertilization duct, but did not draw it. More recently, R. europaea was included in studies relating to molecular phylogeny ( Grande et al., 2002) and feeding ecology ( Megina & Cervera, 2003).

Figures

Figure 1. Roboastra gracilis: living specimens from: A, Fiji (photo K. Tucker); B, Cebu, Philippines (photo M. Miller); C, Sulawesi, Indonesia (photo L. Warren); and D, Hawaii (photo P. Fiene).

Figure 2. Radular morphology of Roboastra gracilis. Scanning electron micrographs. A, left half of the radula (WAMS23233). B, left half of the radula (CASIZ 083858). C, inner lateral teeth (CASIZ 083858). Scale bars = 30 Mm.

Figure 3. Drawings of reproductive systems of Roboastra spp. A, R. gracilis. B, R. luteolineata. C, R. tigris. D, R. europaea (adapted from Pola et al., 2003). E, R. caboverdensis. F, R. leonis sp. nov. Scale bar = 1 mm. Abbreviations: am, ampulla; bc, bursa copulatrix; fglm, female gland mass; ga, genital atrium; p, penis; pr, prostate; rs, receptaculum seminis, ud, uterine duct; va, vagina; vd, vas deferens; vgl, vaginal gland.

Figure 4. Penial morphology of Roboastra spp. A, R. gracilis (CASIZ 087131), scale bar = 30 Mm; B, R. luteolineata (CASIZ 115739), scale bar = 30 Mm. C, R. tigris (NHMLAC 140747), scale bar = 300 Mm. D, R. europaea (MNCN 15.05/46613), scale bar = 50 Mm. E, R. caboverdensis (MNCN 15.05/46614), scale bar = 90 Mm. F, R. leonis sp. nov. (CASIZ 097577), scale bar = 300 Mm. G-I, detail of the three different kinds of spines in R. caboverdensis (MNCN 15.05/46614), scale bar = 10 Mm. J, T. morosa (CASIZ 142786; 35 mm preserved), scale bar = 20 Mm.

Figure 6. Photographs of living animals: A, Roboastra luteolineata, Papua New Guinea (photo T.M. Gosliner). B, R. tigris, Mar de Cortés (photo H. Debelius). C1, R. europaea, Carroñera, Spain (light form) (photo L. Tocino). C2, R. europaea, Tarifa, Spain (black form) (photo T.M. Gosliner. D, R. caboverdensis, Cape Verde (photo P. Wirtz). E, R. leonis sp. nov., the Galápagos Islands (photo T.M. Gosliner).

Figure 7. Scanning electron micrographs of the radula. A, right half of the radula, Roboastra luteolineata (CASIZ 115739), scale bar = 300 Mm. B, innermost lateral teeth, R. luteolineata (CASIZ 086319), scale bar = 30 Mm. C, left half of the radula, R. tigris (CASIZ 057321), scale bar = 300 Mm. D, outermost lateral teeth, R. tigris (CASIZ 068357), scale bar = 90 Mm. E, innermost lateral teeth, R. europaea (CASIZ 166053); white lines indicate the bifid upper cusp of some inner teeth, scale bar = 200 Mm. F, right half of the radula, R. caboverdensis (MNCN 15.05/46614), scale bar = 300 Mm. G, innermost lateral teeth, R. caboverdensis (MNCN 15.05/46614), scale bar = 90 Mm. H, right half of the radula, R. leonis sp. nov. (CASIZ 097577), scale bar = 300 Mm.