Jorunna spazzola

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 : 179-180

Jorunna spazzola (Er. Marcus, 1955)

( Figures 1 H; 17–18)

Awuka spazzola Er. Marcus, 1955: 156, figs. 180–192; Er. Marcus (1958b: 57); Ev. Marcus (1970: 210). Jorunna spazolla : Ev. Marcus (1976c: 35); Edmunds & Just (1985: 55, figs. 2B, 4B); García et al. (2008:154); Rios (2009: 428).

Type material. Syntypes: MZSP 75960, June/ November 1953 and April 1954, up to 10.0 mm long alive [6].

Type locality. Ilha de São Sebastião, São Paulo state, Brazil.

Material examined. Syntypes; Brazil: Rio de Janeiro state: Cabo Frio, Ilha do Papagaio: MNRJ 13196, 27 /x/ 2007, V. Padula coll. [2; two dissected]; Arraial do Cabo, Praia do Forno: MNRJ 13190, 16 /v/2008, V. Padula coll. [3, two dissected]; MNRJ 12372, 28 /xii/2007, J. Alvim coll. [1]; MNRJ 11707, 23 /vi/2007, J. Alvim coll. [1]; São Paulo state: Ilha de São Sebastião: MZSP 75960 [6; one dissected].

Geographical distribution. Barbados (Edmunds & Just, 1985); Brazil: Rio de Janeiro state: Cabo Frio (García et al., 2008), Arraial do Cabo (present study); São Paulo state: Ilha de São Sebastião, Ilha do Cardoso, Cananéia, Baía de Trapandé (García et al., 2008).

Description. External morphology ( Figures 1 H; 17G–H): elongated body, slightly tapered in posterior portion, up to 9.0 mm long alive, 1.5 times longer than wide. Mantle densely covered by equidistant caryophyllidia (average: 173 µm in height); caryophyllidia lower at mantle edge and in center of mantle than those at sides of mantle; in each caryophyllidium five or six spicules protrude around tubercle, which presents an oval ciliated apex. Rhinophoral and branchial sheaths prominent, covered by caryophyllidia. Rhinophores long with 8 to 10 diagonal perfoliations and cylindrical apex. Gill with five to ten retractile, bi-tripinnate branchial leaves, arranged to form a closed circle around high anal cone. Foot narrower than mantle; anteriorly bilabiate and notched on upper “lip”. Oral tentacles triangular and flattened. Color of living specimens ranges from purplish gray to whitish gray, with several rounded blotches on dorsum, darker than rest of mantle, of irregular sizes and arrangement; ventrally, whitish; rhinophores and branchial leaves with same tone as mantle with white tips.

Labial cuticle and radula ( Figures 17 A–F): labial cuticle with yellow lateral plates with numerous elements with rounded apex. Radula formula 22 x 13.0. 13 in preserved specimen measuring 7.0 mm in length; lateral teeth hook-shaped; innermost lateral teeth with one or three or four denticles on inner surface of teeth. Subsequent lateral teeth smooth, larger and more developed in center of rows. Four to five marginal teeth elongated, thin and branched, with two or four finger-like projections on their distal part.

Reproductive system ( Figure 18 ): hermaphrodite duct connected to rounded and not convoluted ampulla. Postampullary gonoduct short, connecting to oviduct and prostate. Prostate granular, not divided in two portions, probably due to small size of specimens. Vas deferent duct elongated and convoluted, approximately of same diameter of vagina. Accessory gland attached to common atrium, between penis and vagina; accessory gland tubular and approximately four times wider than deferent duct; with spine straight at base and curved at distal portion, length about 165 µm. Vagina elongate and narrow passing behind prostate and female gland and, folding over bursa copulatrix. Round bursa copulatrix. Bursa serially arranged, vaginal duct slightly convoluted and connecting to seminal receptacle; uterine duct short. Seminal receptacle approximately 60% of length of bursa copulatrix.

Remarks. Only one lot (MZSP 75960), containing six specimens, was found in MZSP labeled as Awuka spazzola by Marcus, without additional information about locality and date. In the original description, Er. Marcus (1955) mentioned seven specimens collected at Ilha de São Sebastião in June / November 1953 (3 specimens) and April 1954 (4 specimens), and a few years later Ev. Marcus (1976c: 35) reviewed the species and referred to the original material and serial sections as “the 6 available specimens”. Thus, we believe that MZSP 75960 corresponds to the type-series (syntypes), and the missing specimen was used for the histological sections.

The specimens studied here present the same characteristics as mentioned in the original description, except for some minor differences with respect to the proportions of ducts and organs of the reproductive system. Furthermore, we failed to observe the two portions of the prostate, probably due to the small size of the specimens and fixation state of the potential syntypes. However, we are able to report variation of the innermost lateral tooth. Ev. Marcus (1976c) described the innermost lateral tooth as possessing a single denticle, whereas we found specimens with one, three or four denticles ( Figs. 17 B–D), not in the same radula.

Valdés et al. (2006) considered Discodoris mortenseni Ev. Marcus & Er. Marcus, 1963 as a possible (using a question mark in the synonymy) synonym of Jorunna spazzola , and thus used the older name J. spazzola from the Caribbean. Indeed, Discodoris mortenseni belongs to the genus Jorunna according to the morphology of caryophyllidia, radula and the reproductive system. However, besides being smaller (3.0 mm to 12.0 mm in length) than J. mortenseni (20.0 mm to 28.0 mm in length), J. spazzola can be distinguished from J. mortenseni on the basis of the general coloration of the body, radula and rhinophores. In J. spazzola , the body and gill are grayishpurple with gray blotches, whereas J. mortenseni is pink or pink-gray with brown spots and the gill is dark. The radula of J. spazzola is longer than it is wide (22 x 13.0.13), whereas in J. mortenseni it is wider than it is long and there are more teeth per row (14 x 32.0.32/ 22 x 39.0.39). In J. spazzola , there are denticles on the inner surface of the inner lateral tooth, which are absent in J. mortenseni ; the rhinophores of J. spazzola present eight to ten perfoliations, whereas J. mortenseni has 20 perfoliations. Based on these differences we can conclude that J. mortenseni is distinct from J. spazzola . Furthermore, the specimens illustrated by Valdés et al. (2006) have a gill that is proportionally smaller than that of J. spazzola , and the tiny dark spots on the dorsum are quite different from the rounded blotches in the specimens studied here ( Fig. 1 H).

Camacho-García and Gosliner (2008) considered Jorunna luisae Ev. Marcus, 1976c, from Italy, as a synonym of J. spazzola . However, the synonymy was based on a study of the same specimen as that illustrated by Valdés et al. (2006). Camacho-García and Gosliner (2008; pag. 159, Figs. 13 A–B) described the reproductive system of the holotype of J. luisae , allowing us to compare the differences between the original description of J. spazzola and the specimens analyzed here. The deferent duct is thinner than the vagina in J. luisae , whereas J. spazzola presents a deferent duct that is approximately as thick as the vagina ( Fig. 18 ); in some specimens we found the deferent duct slightly thicker. In J. luisae the ampulla is convoluted, whereas in J. spazzola it is rounded, not convoluted ( Fig. 18 ); J. luisae presents a convoluted, short and wide accessory gland, whereas in J. spazzola the tubular accessory gland is long and thin and is not convoluted ( Fig. 18 ). We consider, therefore, that J. luisae and J. spazzola are different species.

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 13. Diaulula greeleyi, SEM photographs; A, detail of the labial cuticle; B, innermost lateral teeth; C, midlateral teeth; D, marginal teeth; E, general view of the dorsum; F, detail of the caryophyllidium. A (MNRJ 13193); B – D (MNRJ 13994); E – F (MNRJ 12307).

FIGURE 17. Jorunna spazzola, SEM photographs; A, detail of the labial cuticle; B – D, detail of the innermost lateral tooth; E – F, marginal teeth; G – H, caryophyllidia. A, C – F (MNRJ 13190); B (MNRJ 13196); G – H (Syntype, MZSP 75960).

FIGURE 18. Jorunna spazzola (Syntype, MZSP 75960); A, general view of reproductive system; B, copulatory spine. Abbreviations: ag, accessory gland; am, ampulla; bc, bursa copulatrix; dd, deferent duct; f, female glands; pr, prostate; s, seminal receptacle; u, uterine duct; va, vagina.