Taxonomic review of the family Discodorididae (Mollusca: Gastropoda: Nudibranchia) from Brazil, with descriptions of two new species
Author
Alvim, Juliana
Author
Pimenta, Alexandre Dias
text
Zootaxa
2013
3745
2
152
198
journal article
10.11646/zootaxa.3745.2.2
c32092a5-be17-4b13-8c8b-a7b1e7b334a8
1175-5326
248699
D87FBB64-5DE2-4D19-9338-6E9BE212FAEF
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.