Hoplodoris hansrosaorum Domínguez, García & Troncoso, 2006

Alvim, Juliana & Pimenta, Alexandre Dias, 2013, Taxonomic review of the family Discodorididae (Mollusca: Gastropoda: Nudibranchia) from Brazil, with descriptions of two new species, Zootaxa 3745 (2), pp. 152-198 : 159-160

Hoplodoris hansrosaorum Domínguez, García & Troncoso, 2006

( Figures 1 B; 5–6)

Hoplodoris hansrosaorum Domínguez et al. 2006: 150 –155, figs. 1–14, tbl. 1; García et al. (2008: 146); Rios (2009: 427); Padula et al. (2012: 3).

Type material. Holotype: MZSP 52190, 28 July 1999, 27.0 mm long alive, J. S. Troncoso & F.J. García colls.

Type locality. Ilha de Cabo Frio, Arraial do Cabo, Rio de Janeiro state, Brazil.

Material examined. Holotype; Brazil: Alagoas state: Saco de Pedra: MNRJ 12924, 08 /i/2008, V. Padula coll. [1; one dissected]; Rio de Janeiro state: Cabo Frio: Ilha do Papagaio: MNRJ 13247, 30 /iii/2008, V. Padula coll. [1]; Arraial do Cabo: Prainha: MNRJ 13176, 03 /iii/2007, P. M. S. Costa coll. [1; one dissected].

Geographical distribution. Brazil: Alagoas state: Saco de Pedra (Padula et al., 2012); Rio de Janeiro state: Cabo Frio: Ilha do Papagaio (present study); Arraial do Cabo: Prainha (present study), Ilha de Cabo Frio (Domínguez et al., 2006).

Description. External morphology ( Figures 1 B; 5E): body elliptical, slightly depressed, up to 26.0 mm long alive. Mantle hardened, densely covered by rounded tubercles irregularly arranged with different diameters; tubercles lower at mantle edge and in center of mantle (79 µm to 144 µm) than those on sides of mantle (224 µm to 250 µm); tubercles composed by spicules in two classes of size, one class with average 28 µm and another class with average 145 µm. Rhinophoral and branchial sheaths prominent and lobulated; rhinophoral sheaths with one row of tubercles; branchial sheaths with two rows of tubercles. Rhinophores long, with cylindrical apex, 17 to 22 diagonal perfoliations. Gill with eight retractile, tripinnate branchial leaves; anal cone high. Foot four times narrower than mantle; anteriorly, bilabiated and notched on upper “lip”. Oral tentacles conical and short. Color of living specimens predominantly orange, reddish in center of mantle, yellowish in lateral part and, mantle edge white; yellow tubercles with white pigment surrounding it; ventrally, white with some red spots smallest and more concentrated on ventral part of foot than on lateral of foot and mantle; reddish rhinophores with some white spots on perfoliation and cylindrical apical part; branchial leaves located anteriorly yellowish and more posterior ones translucent reddish.

Labial cuticle and radula ( Figures 5 A–D): Labial cuticle with rounded elements more or less conical. Radular formula 22 x 4.29.0.29. 4 in preserved specimen measuring 22.0 mm in length; innermost lateral teeth hook-shaped with one or two denticles in its inner surface; subsequent lateral plates hook-shaped, larger and more developed in center of rows, its inner surface smooth and its outer surface serrate with up to 40 denticles, number of denticles increasing along row; four marginal teeth spatulate and pectinate.

Reproductive system ( Figures 5 F–H; 6): hermaphrodite duct connecting to convolute ampulla. Postampullary gonoduct very short that connects to oviduct and prostate. Prostate granular, divided into two parts approximately of same size, less dense part distal, denser proximal part. Vas deferens elongated, narrow and convoluted; near gonopore enlarged, containing penis. Penis with tiny spines surrounding its most anterior portion. Accessory gland elongated and tapered in distal part; with cylindrical cuticle stylet. Vagina elongated, two times thicker than deferent duct. Rounded bursa copulatrix; bursa serially arranged, vaginal duct folding once and connecting to short-stalked seminal receptacle. Uterine duct short. Bursa and receptacle of similar size.

Remarks. Among the eight species of the genus Hoplodoris , the only one recorded from the Atlantic Ocean is Hoplodoris hansrosaorum , which was described on the basis of only one specimen. In the present paper, three additional specimens are described, allowing us to evaluate intraspecific variation and to recognize new features. The genus Hoplodoris is characterized by an accessory gland with a copulatory spine and a penis with hooks (Valdés, 2002). Although Domínguez et al. (2006) did not describe the penis, an accessory gland with a long tapering stylet was recorded. In the specimens studied presently, the penis bears a few tiny spines in its anterior portion ( Figs. 5 F–G) and a cuticular stylet is present in the accessory gland ( Fig. 5 H), which is very similar to that described by Domínguez et al. (2006).

Domínguez et al. (2006) described the inner surface of the innermost lateral teeth as smooth; however, in all specimens examined here, one or two denticles are present ( Fig. 5 B). Because there is no species in the genus Hoplodoris with a smooth inner surface of the innermost lateral teeth, Domínguez et al. (2006) were probably referring to the subsequent lateral teeth.

Some aspects of the reproductive system might exhibit some variation: the prostate can be elongated (this study; Fig. 6 ) or rounded (Domínguez et al. 2006); the seminal receptacle is approximately the same size as the bursa copulatrix (this study; Fig. 6 ), whereas Domínguez et al. (2006) reported the bursa copulatrix as being three times wider. Based on the illustrations provided by Domínguez et al. (2006: 151; Fig. 6 ), the penis bulb is enlarged until it opens in the deferent duct, yet in the specimens studied here, there are no differences between the deferent duct and the penial bulb in terms of width ( Fig. 6 A).

Figures

FIGURE 1. Living specimens; A, Thordisa diuda (MNRJ 13195, 9 mm), photo: V. Padula; B, Hoplodoris hansrosaorum (MNRJ 12924, 22 mm); C, Geitodoris pusae (MNRJ 11712, 12 mm); D, Discodoris branneri (MNRJ 14922, 87 mm); E, Discodoris hummelincki (MNRJ 13997, 32 mm); F, Diaulula greeleyi (MNRJ 14974, 10 mm); G, Rostanga byga (MNRJ 12371, 5 mm); H, Jorunna spazzola (MNRJ 13196, 5 mm), photo: V. Padula.

FIGURE 5. Hoplodoris hansrosaorum, SEM photographs; A, labial cuticle; B, inner surface of the innermost lateral tooth; C, midlateral tooth; D, marginal teeth; E, tubercle of the dorsum; F – G, penis, spines indicated by white arrow; G, detail of the spines; H, stylet of the accessory gland. A – C, E, H (MNRJ 13176); D, F – G (MNRJ 12924).

FIGURE 6. Hoplodoris hansrosaorum (MNRJ 13176); A, general view of reproductive system; B, detail near the uterine duct opening; C, detail near the ampulla; D, accessory gland. Abbreviations: am, ampulla; ag, accessory gland; bc, bursa copulatrix; dd, deferent duct; f, female glands; ov, oviduct; pr, prostate; s, seminal receptacle; u, uterine duct; va, vagina.