Zoosyst. Evol. 94 (1) 2018, 1-15 | DOI 10.3897/zse.94.14959

> PENSUFT.

museum fur naturkunde

Revision of Platydoris angustipes and description of a new species
of Platydoris (Gastropoda: Nudibranchia) from southeastern Brazil

based on comparative morphology

Patricia O. V. Lima!, Luiz Ricardo L. Simone!

1 Museu de Zoologia da Universidade de SGo Paulo, Cx. Postal 42494; 04299-970 Sao Paulo, SP, Brazil

http://zoobank. org/57027940-2E36-4170-A90C-B8F17E7C72B6

Corresponding author: Patricia O. V. Lima (patylima84@gmail.com)

Abstract

Received 10 July 2017
Accepted 10 November 2017
Published 2 January 2018

Platydoris angustipes (Morch, 1863) is a common nudibranch in the Western Atlantic,
ranging from Florida, USA, to Rio de Janeiro, Brazil. In this study, we examined the
anatomy of P. angustipes along its distribution, including its type material. Our analysis

shows consistent differences between the Caribbean and Brazilian populations, mainly

Academic editor:
Matthias Glaubrecht

in the reproductive system, radular teeth and odontophore musculature. This strongly
suggests that the two populations actually belong to distinct species. The Brazilian popu-

lation is described herein as a new species, Platydoris guarani sp. n.

Key Words

Discodorididae
Platydoris angustipes
Platydoris guarani
new species

Introduction

The nudibranch Platydoris angustipes (Morch, 1863) is
presently considered a widespread species in the western
Atlantic, ranging from the Caribbean to southern Brazil,
and reaching Ascension Island to the east (Rosenberg et
al. 2009; Padula et al. 2017). It is very commonly found
in Brazilian waters (Marcus and Marcus 1967; Garcia et
al. 2002; Valdés et al. 2006; Padula et al. 2012; Alvim
and Pimenta 2013; Galvao-Filho et al. 2015; Padula
et al. 2017).

In their phylogenetic analysis of the genus Platydoris,
Dorgan et al. (2002) reviewed the morphological data
from the literature noting the distribution of P. angustipes
in the Caribbean Sea, but not in Brazil. However, Alvim
and Pimenta (2013), in a taxonomical revision of Disco-
dorididae, list P angustipes for Brazilian waters.

Since there is doubt whether the Caribbean and Bra-
zilian populations of Platydoris angustipes are the same

taxa, in the present study we performed a detailed com-
parative anatomical survey of them. This included the
holotype, from Saint Thomas (U.S. Virgin Islands), and
specimens collected in Honduras, the Virgin Islands and
Brazil (Rio de Janeiro state). We were able to recognize
significant morphological differences that led us to the
description of the Brazilian population as a new species.

Materials and methods

The studied material come from museum collections,
consisting of specimens preserved in 70% ethanol. Dis-
sections were performed under a stereomicroscope by
standard techniques, with the specimens immersed in
fixative (Simone 2004, 2011). The initial steps of the an-
atomical investigation were done through a longitudinal
cut on the tissue covering the dorsal visceral mass. Di-
gestive, circulatory, excretory, reproductive and central

Copyright Patricia O. V. Lima and Luiz Ricardo L. Simone. This is an open access article distributed under the terms of the Creative Commons Attribution License
(CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

2 Lima, P V. & Simone, L. R. L.: Revision of Platydoris angustipes and description...

nervous systems were investigated in detail. The termi-
nology used for odontophore muscles was based on Pon-
der et al. (2008), Simone (2011) and Lima and Simone
(2015). Digital photographs were taken at each dissection
step. Illustrations were prepared with the aid of a camera
lucida. Scanning electron microscopy (SEM) images of
the radula were obtained at MZSP.

Institutions abbreviation: CAS — California Academy
of Sciences (San Francisco, USA); ZMUC - Statens Na-
turhistoriske Museum (Copenhagen, Denmark); MZSP —
Museu de Zoologia da Universidade de Sao Paulo (Sao
Paulo, Brazil); UFBA — Universidade Federal da Bahia
(Bahia, Brazil).

The following abbreviations are used herein: aa: ante-
rior aorta; ab: afferent branchial vein; an: anus; am: am-
pulla; ap: posterior aorta; au: auricle; at: aortic trunk;
be: bursa copulatrix; bg: blood gland: bs: buccal sphinc-
ter; ce: cerebral ganglia; cp: pedal commissure; cu: cae-
cum; dd: duct of digestive gland; dg: digestive gland;
ds: salivary duct; es: oesophagus; ev: efferent branchi-
al vein; ey: eye; fg: female gland; ft: foot; gb: buccal
ganglia; ge: gill circle; ge: gonopore; gf: gill filament;
gg: gastro-oesophageal ganglia; go: gonad: gp: pedal gan-
glia; hd: hermaphrodite duct; in: intestine; mo: mouth;
m2 — m10: odontophore muscles; mt: oral tube muscle;
ne: nephrostome; oc: odontophore cartilage; ot: oral
tube; ov: oviduct; pa: papilla; pe: pericardium; pe: pe-
nis; pl: pleural ganglia; pr: prostate; ra: radula; rg: rhi-
nophoral ganglia; ri: rhinophore; rm: retractor muscle
gill; rp: reproductive system; rs: radular; sac; rv: renal
vesicle; sg: salivary gland; st: stomach; sn: nervous sys-
tem; sp: spine; sr: seminal receptacle; to: oral tentacle;
ud: uterine duct; va: vagina; vd: vas deferent; ve: ven-
tricle; vp: reproductive system vein; vn: nervous system
vein: vs: radular sac vein.

Results

Family Discodorididae Bergh, 1891
Genus Platydoris Bergh, 1877

Type species. Doris argo Linnaeus, 1767, by subsequent
designation (O’ Donoghue 1929).

Platydoris angustipes (Moérch, 1863)
Figures 1-6

Doris (Argus) angustipes Morch, 1863: 32

Platydoris angustipes var. alaleta Bergh, 1877: 505, pl. 58, figs. 13-18.

Platydoris rubra White, 1952: 118, fig. 17, pl. 6, fig. 6.

Platydoris angustipes: Ev. Marcus and Er. Marcus 1967: 93, fig. 112;
Er. Marcus and Ev. Marcus 1970: 67, fig. 121; Meyer 1977: 301;
Humann 1992: 243; Dorgan et al. 2002: 282, figs. 1B, 2B, 11-13;
Valdés et al. 2006: 182; Debelius and Kuiter 2007: 245; Cama-
cho-Garcia et al. 2014: 121; Goodheart et al. 2016: 9, fig.4f.

Type locality. St. Thomas, U. S. Virgin Islands.

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Redescription. External morphology (Figure 1A—E):
Size ~25 mm length, ~20 mm width. Body dorsoventral-
ly flattened and wide (Fig. 1A, B). Foot not exceeding
notum (Fig. 1B). Rhinophores with ~19 transverse lamel-
lae, rhinophoral sheaths with small lobes (Fig. 1C). Gill
composed of six tripinnate branchial leaves, arranged in
branched fashion with anus in middle of rachis; branchial
sheaths also with small lobes (Fig. 1E). Mouth opens in
anterior ventral region, between anterior region of notum
and foot. Digitiform tentacles present. Anterior border of
foot bilabiate, with longitudinal groove (Fig. 1B).

Haemocoel organs (Figure 2A—B): Pericardium and
posterior half of visceral mass occupying ~15% of haemo-
coel volume. Buccal mass located anteriorly, occupying
~10% of haemocoel volume. Nervous system positioned
dorsally in relation to buccal mass, covered by blood
gland, occupying ~5% of haemocoel volume. Reproduc-
tive system on right side of animal, occupying ~25% of
haemocoel volume. Stomach on left side of animal, in-
testine with small curve on its anterior portion; digestive
gland system occupying ~45% of haemocoel volume.

Circulatory and excretory systems (Figures 1D, E;
2A-C): Pericardial cavity dorsal, located posteriorly to
digestive gland and anteriorly to gill circle (Fig. 2A).
Afferent and efferent branches located inside each gill
filament, flowing from and to afferent and efferent bran-
chial veins, respectively (Fig. 1D). Gill retractor muscle
split, originating from base of gill circle, running longi-
tudinally up to half of foot, inserting into dorsal surface
of foot (Fig. 2B). Auricle funnel-like (wider anteriorly),
with thin walls. Ventricle slightly taller than wide, with
thick muscular walls (Fig. 2C). Aortic trunk branches
very close to ventricle; anterior artery irrigates reproduc-
tive system, buccal mass, odontophore and nervous sys-
tem posterior artery irrigates stomach and digestive gland
(Fig. 2C). Renal vesicle located on dorsal right side of
pericardium, near the base of auricle, connecting to inner
surface of pericardium, ~1/6 of ventricle size (Fig. 2A).
Renal chamber extending from dorsal to medial sinus, an-
teriorly connected to renal vesicle, extending posteriorly
to center of gill circle (Fig. 1E). Nephrostome readily vis-
ible. Blood gland clearly divided in anterior and posterior
portions (Fig. 2A).

Digestive system (Figures 1E; 2A—B, D-E; 3A—E;
6A-C): Oral tube composed of outer and inner lips, with
thick transversal fold; mt, three long pairs of retractor
muscles of buccal mass, originating on oral tube and run-
ning dorsally and ventrally along it; inserting in the side
of the body; about four times as wide and three times as
long as m10 (Fig. 2D, E). Odontophore oval, connected
to oral tube by pair of ventral protractor muscles (m10);
thin longitudinal dorsal and ventrolateral protractors of
oral sphincter originating in anterior region of odon-
tophore and inserted in posterior region of integument,
close to oral tube (Figs 2E; 3C). Oral sphincter surround-
ing chitinous part of oral tube (Fig. 2D). Odontophore
muscles: m2, pair of strong buccal mass retractor mus-
cles, four times longer than wide, originating on anterior

Zoosyst. Evol. 94 (1) 2018, 1-15 3

Figure 1. Platydoris angustipes, fixed animal A dorsal view B same, ventral view C rhinophore D gill filament with
transversely sectioned showing afferent and efferent branchial ring E gill circle. Scale bars: 5 mm (A, B); 1 mm (C);
2 mm (D, E).

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4 Lima, PV. & Simone, L. R. L.: Revision of Platydoris angustipes and description...

VS

A
SEN a.
22 by tt W WN mt
QoS Hi ASS
x ! ; & | | 7

3g es

Figure 2. Platydoris angustipes. Visceral mass A dorsal view B same, ventral view C circulatory system, dorsal view.
Anterior digestive system D dorsal view E same, ventral view. Scale bars: 5 mm (A, B); 2 mm (C-—E).

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Zoosyst. Evol. 94 (1) 2018, 1-15 5

Figure 3. Platydoris angustipes. A medium digestive system. Odontophore B dorsal view with radula C same, ventral
view D same, dorsal view with removed radula E same, dorsal view with folded down muscles. Scale bars: 2 mm.

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6 Lima, P. V. & Simone, L. R. L.: Revision of Platydoris angustipes and description...

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ADS

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Figure 4. Platydoris angustipes. Reproductive system A general view B detail of connection of uterine duct C detail
of vagina’s spines D detail of internal part of insertion of vas deferens E detail of penis’s spines. Scale bars: 2 mm (A,
B); 1 mm (C-E).

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Zoosyst. Evol. 94 (1) 2018, 1-15

Figure 5. Platydoris angustipes. Nervous system A dorsal view B same, ventral view C buccal and gastroesophageal

ganglia. Scale bars: 1 mm.

dorsal odontophore, running laterally to m4 and inserted
ventrally in dorsal portion of foot, bifurcate on inser-
tion (Fig. 3B—D); m4, pair of strong and broad dorsal
tensor muscles, as long as wide, covering ~2/3 of carti-
lage, inserted in ventral portion of subradular membrane
(Fig. 3D, E); m5, pair of dorsal auxiliary tensor muscles,
twice as long as wide, originating on posteriormost re-
gion of odontophore cartilage, covering ~1/3 of posterior
cavity of odontophore, as long as m4, but with ~1/3 of its
width, inserting in ventral side of subradular membrane
around radular sac (Fig. 3D, E); m6, unpaired horizon-
tal muscle, with transversal fibers connecting to median
surface of left and right odontophore cartilages, about
same length and half as wide as m4, posterior portion as
wide as anterior portion (Fig. 3D, E); m7, pair of thin and
narrow muscles, originating on inner surface of odonto-
phore cartilages, running together posteriorly, inserting
into radular sac (Fig. 3D, E); m9, unpaired and horizontal
muscle, originating on posterior portion of m4, connect-
ing of the two components of the m4 pair (Fig. 3D, E).
Pair of odontophore cartilages elliptical, occupying ~2/5
of odontophore volume (Fig. 3D, E). Subradular mem-
brane thin, strong, translucent. Radular sac ~1/4 as large
as odontophore. Radular teeth (Fig. 6A—C): rachidian
teeth absent; formula 42 x 62.0.62 (in 25 mm long speci-
men, CASIZ 76667). Each lateral tooth with broad base,
tapering towards apex, hook-shaped, with single termi-
nal cusp; two outermost teeth spatulate. Pair of salivary

glands long, tubular; duct inserting in anterior region of
esophagus, extending posteriorly to ventral middle region
of digestive gland (Fig. 2B). Esophagus simple, originat-
ing dorsally to odontophore, inserting directly in anterior
region of stomach; internal longitudinal folds with same
diameter along entire length (Figs 2D, E; 3A). Stomach
oval, occupying ~30% of visceral mass volume, with
folds at the center of entire inner surface (Figs 2A; 3A).
Common opening for esophagus and stomach located on
digestive gland. Intestine with longitudinal folds along its
entire length; diameter ~1/2 that of esophagus and more
uniform than it (Fig. 3A). Digestive gland dark beige,
cone-shaped; largest organ of visceral mass, occupying
~40% of its volume; anterior portion about twice as wide
as posterior portion; inner surface of gland sponge-like,
bearing two distinct main ducts (Fig. 3A). Anus opening
into anal papilla in the center of gill circle, ~1/4 of gill
filament length (Fig. 1E).

Genital system (Figure 1B; 2B; 4A—E): Located be-
tween buccal mass and digestive gland, mostly dorsal-
ly-positioned on right side of animal (Fig. 2B). Genital
opening on ventral right side, on anterior third of animal,
located between foot and notum (Fig. 1B). Gonad im-
mersed in digestive gland, difficult to distinguish from
it. Hermaphrodite duct thin, long. Ampulla located on fe-
male gland, elongated and tubular. Prostate rounded, glan-
dular, connected with female gland duct, ~1/3 of ampulla
length (Fig. 4A, D). Vas deferens short, ~1/5 of ampulla

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8 Lima, P. V. & Simone, L. R. L.: Revision of Platydoris angustipes and description...

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Lo ti Wh Wi ce

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Figure 6. SEM of radula of Platydoris angustipes. A panoramic view B central region with rachidian tooth absent C
lateral teeth. Scale bars: 300 um (A); 100 um (B); 30 um (C).

(Fig. 4D). Penis’ muscle absent. Penis muscular, cylin-
drical and elongated, about three times longer than pros-
tate; thin folds on internal surface, with cartilage between
them and three small tubercles each with a central spine
(Fig. 4D, E). Female gland well-developed, rounded, oc-
cupying ~1/5% of reproductive system volume; divided
into mucus gland (~2/3 of female gland, color beige) and
albumen gland (~1/3 of anteriormost region, dilated, 1r-
regularly shaped, color dark brown) (Fig. 4B). Oviduct
occupying ~1/2 of female gland’s volume (Fig. 4A). Uter-
ine duct thin, relatively short, ~1/7 of vagina length; lo-
cated on the base of seminal receptacle, inserted in female
gland near oviduct (Fig. 4B). Seminal receptacle round-
ed, as large as bursa copulatrix, ~1/3 of vagina length;
connected to bursa copulatrix through stalk with ~1/2 of
vagina length (Fig. 4B). Bursa copulatrix rounded, ~1/3
of vagina length, connected directly to vagina (Fig. 4B).
Vagina cylindrical, elongated, approximately as long as
and twice as wide as penis; internal surface with cartilage
between folds and five large tubercles each with a central
spine; located dorsally in relation to prostate and parallel
to penis in genital opening (Fig. 4 A-C).

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Nervous system (Figure 5A—C): Located dorsally in
relation to odontophore, mostly covered by blood gland.
Pair of cerebral and pleural ganglia fused with one an-
other. Pedal ganglia ventrally fused with cerebral and
pleural ganglia, but not fused between themselves. Pedal
commissure simple, broad and short, surrounding esoph-
agus and salivary glands (Fig. 5B). Buccal ganglia short,
located ventrally to odontophore between radular sac
and anterior portion of esophagus, connected to cerebral
ganglia through long and slender connective tissue, unit-
ed to gastro-esophageal ganglia by short connective tis-
sue. Gastro-esophageal ganglia circular, ~1/4 of buccal
ganglia length (Fig. 5C). Rhinophoral (olfactory) ganglia
inconspicuous. Dorsal eyes located on cerebral ganglia
(Fig. 5A).

Distribution. United States of America (Florida and Vir-
gin Islands) (Marcus and Marcus 1967; Marcus and Mar-
cus 1970); Cuba (Guanahacabibes Peninsula) (Espinosa
et al. 2012); Cayman Islands (Hess et al. 1994); Panama
(Bocas del Toro) (Goodheart et al. 2016); Jamaica (Mar-
cus and Marcus 1970); Curacao (Marcus and Marcus

Zoosyst. Evol. 94 (1) 2018, 1-15

1970); Trinidad & Tobago (White 1952); Ascension Is-
land (Padula et al. 2017).

Habitat. On reefs, tide pools, from 0 to 73 m depth.

Material examined. CARRIBEAN SEA, West Indies,
Lesser Antilles, Martinique, cliffs S of St. Pierre, CASIZ
76667, 1 specimen (William Liltved on “Gloriamaris”,
28/1x/1986, 10-85ft — Liltved — West Indies Cruise 1986);
HONDURAS, MZSP 75996, 1 specimen (Col. Marcus,
P-938); Saint Thomas, ZMUC-GAS 1505, 1 specimen
(Riise 152 — Holotype of Doris angustipes);, Saint Croix,
Virgin Island, ZMUC-GAS 2020, 1 specimen (Riise 1860
— Holotype of Platydoris angustipes alaleta).

Platydoris guarani sp. n.

http://zoobank.org/632F273F-E1D3-4808-8D68-D21199975575
Figures 7-11

Platydoris angustipes Er. Marcus, 1957: 422, fig. 81-89; Ev. Marcus
1972: 79; Garcia et al. 2002: 53, fig.2K; Garcia et al. 2008: 148;
Alvim and Pimenta 2013: 186, figs. 2C; 21-22; Padula et al. 2012:
3 (non Morch 1863).

Type material. Holotype: BRAZIL, Rio de Janeiro, Ilha
Grande, Angra dos Reis, MZSP 86082, 1 specimen (E.P.
Gongalves, L.R. Simone & P. Oristanio, coll., 24/1x/2006,
17m depth, Ponto 3, Pinguino Wreck). Paratype: BRAZIL,
Rio de Janeiro, Ilha Grande, Angra dos Reis, MZSP 134877,
2 specimens (E.P. Gongalves, L.R. Simone & P. Oristanio,
coll., 24/ix/2006, 17m depth, Ponto 3, Pinguino Wreck).

Type locality. Brazil, Rio de Janeiro state, Angra dos Reis.

Etymology. The specific epithet is a noun in apposition,
derived from the native Guarani indigenous people, some
tribes of which still reside in Rio de Janeiro.

Diagnosis. Body of orange color, with a white ribbon on
its edge and brown spots just above the ribbon (they can
be seen both dorsally and ventrally). Radula with outer-
most teeth not spatulate, with apex hook-shaped; cusp
simple and smooth. Presence of m4a and m7b odonto-
phore muscles. Gonad readily visible. Absence of spines
on internal surface of penis and vagina.

Description. External morphology (Figure 7A-C):
Size ~60 mm length, ~40 mm width. Body color orange
with white ribbon on its edge and brown spots just above
the ribbon that can be seen both dorsally and ventrally
(Fig. 7A—B). Body flattened and wide with small tuber-
cles around dorsum. Rhinophores with ~25 transver-
sal lamellae, very thin; color dark orange; rhinophoral
sheaths with very small lobes (Fig. 7C). Gill composed of
six white tripinnate branched branchial leaves, arranged
in circular fashion surrounding anus; branchial sheaths
also with very small tubercles (Fig. 7C). Mouth opens in
anterior ventral region, between anterior region of notum

9

and foot. Digitiform tentacles present. Anterior border of
foot bilabiate and longitudinally notched.

Haemocoel organs: Of similar proportions as P. an-
gustipes (see above).

Circulatory and excretory systems (Figure 8A, B):
Same as P. angustipes, but with renal vesicle very large,
well-developed, of about same length and width as ven-
tricle (Fig. 8B), extending from dorsal to medial sinus,
anteriorly connected to renal vesicle, extending posteri-
orly to center of gill circle and opening in nephrostome
(Fig. 8A). Nephrostome pore not readily apparent.

Digestive system (Figures 8C, D; 9A-D; 11A—C):
Same pattern as P. angustipes, but with the following dif-
ferences: m2, twice as long, not bifurcated on insertion
(Fig. 9A, B); m4a, pair of thin muscles originating in pos-
terior region of m4 and inserting in the middle of odon-
tophore cartilages, dorsally connected to m7b (Fig. 9D);
m7b, pair of thin and short muscles originating in poste-
rior region of m6, with joint insertion with posterior part
of m7 (Fig. 9C, D). Radular sac ~1/5 as large as odonto-
phore (Fig. 9A, B). Radular teeth (Fig. 11A—C): anteri-
or region broader than in P. angustipes; rachidian teeth
also absent; formula 35 x 60.0.60 (in 60 mm long spec-
imen, MZSP86082). Each lateral tooth with broad base,
tapering towards apex, hook-shaped, with single terminal
cusp; outermost teeth narrower than in P. angustipes, in-
ner base width ~1/2 lateral teeth width, apex also hook-
shaped, cusp simple and smooth (Fig. 11C). Pair of sali-
vary glands long, tubular, bulging in anterior portion and
tapering posteriorly; duct inserting in anterior region of
esophagus, extending posteriorly to ventral middle region
of digestive gland (Fig. 8D). Esophagus simple, originat-
ing dorsally to odontophore, inserting directly in anterior
region of stomach; longitudinal folds on inner surface
with same diameter along esophagus’ entire length. Stom-
ach oval, with folds on the center of entire inner surface
(Fig. 8C). Common opening for esophagus, stomach and
caecum located on digestive gland. Intestine with longi-
tudinal folds along its entire length; diameter similar to
that of esophagus; anterior portion S-shaped, about twice
longer than in P. angustipes (Fig. 8C). Caecum: short
elongated sac, located ventrally to stomach, opening in
anterior portion of stomach close to esophageal insertion;
~1/12 length and ~1/5 width of stomach (Fig. 8C). Di-
gestive gland dark beige; largest organ of visceral mass;
cone-shaped, anterior portion about twice as wide as pos-
terior portion; inner surface of gland sponge-like, bearing
distinct main duct. Anus opening into anal papilla on the
center of gill circle, similar to P. angustipes.

Genital system (Figure 10A—B): Located between
buccal mass and digestive gland, longitudinal on right
side of animal. Genital opening on right side, on ante-
rior third of animal, located between foot and notum.
Gonad circling around all digestive gland, but easy to
distinguish, unlike in P. angustipes. Hermaphrodite duct
thin, long. Ampulla located on female gland, elongated
and tubular. Prostate rounded, glandular, of same length
as ampulla (Fig. 1OA). Vas deferens about same length

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10 Lima, PR V. & Simone, L. R. L.: Revision of Platydoris angustipes and description...

Figure 7. Platydoris guarani, living animals. A. Dorsal view, specimen from Papagaio, Cabo Frio, Rio de Janeiro
(MZSP 97331). B. Same, ventral view. C. Living animal with spawning, specimen from Enseada da Meia Lua, Cabo
Frio, Rio de Janeiro (MZSP 97625). All photograph by V. Padula.

as ampulla Penis muscular, cylindrical and very broad,
~1/2 length and three times wider than ampulla, without
spines (Fig. 10A). Female gland well-developed, round-
ed, occupying ~20% of reproductive system volume;
divided into mucus gland (~2/3 of female gland, color
beige) and albumen gland (~1/3 of anteriormost region,
dilated, irregularly shaped, color dark brown). Oviduct
occupying ~1/5 of female gland volume (Fig. 10A).
Uterine duct thin, relatively short, length ~1/10 of vagi-
na length, located on the base of seminal receptacle, in-
serted in female gland near oviduct (Fig. 10B). Seminal
receptacle elongate, as long as bursa copulatrix and ~1/3
its width; connected to vagina through stalk with same
length and ~1/2 width of vagina (Fig. 10B). Bursa cop-
ulatrix rounded, ~1/2 length of vagina, connected to va-
gina posteriorly to seminal receptacle (Fig. 10B). Vagina
cylindrical, very broad, with wide and thick folds, with-
out spines; approximately as long and as wide as penis;

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positioned dorsally in relation to prostate and parallel to
penis in genital opening (Fig. 10B).
Nervous system (Figure): Same as in P. angustipes.

Distribution. Brazil (Valdés et al. 2006). Pernambuco:
Fernando de Noronha (Garcia et al. 2002); Alagoas: Saco
da Pedra (Padula et al. 2012); Bahia: Praia de Itapoa (Gar-
cia et al. 2008); Rio de Janeiro: Cabo Frio: Ilha Comprida;
Arraial do Cabo: Prainha (Alvim and Pimenta 2014).

Habitat. Under stones, associated with sponges and as-
cidians (Garcia et al. 2002), from 0 to 17 m depth.

Material examined. Types. Additional material: BRA-
ZIL, Rio de Janeiro, Enseada da Meia Lua, Cabo Frio,
MZSP 97625, 1 specimens (V. Padula, coll., 23/1v/2010);
Ilha dos Papagaios, MZSP 97515, 1 specimen (V. Padul,
coll., 17/x/2009).

11

Zoosyst. Evol. 94 (1) 2018, 1-15

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Figure 8. Platydoris guarani. A circulatory and excretory system, ventral view B renal vesicle C medium digestive

system, dorsal view D detail of salivar glands. Scale bars: 2 mm (A, B, D); 5 mm (C).

2 Lima, P. V. & Simone, L. R. L.: Revision of Platydoris angustipes and description...

Figure 9. Platydoris guarani. Odontophore. A dorsal view with radula B same, ventral view C same, dorsal view with
removed radula D same, dorsal view, with folded down muscles. Scale bars: 2 mm.

bc

hd

Figure 10. Platydoris guarani. Reproductive system A general ventral view B detail of Bursa copulatrix, seminal re-
ceptacle, uterine duct and vagina. Scale bars: 2 mm.

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Zoosyst. Evol. 94 (1) 2018, 1-15

13

Figure 11. SEM of radula of Platydoris guarani. A panoramic view B central region with rachidian tooth absent C lat-
eral teeth. Scale bars: 300 um (A); 100 um (B); 30 um (C).

Discussion

In the previous anatomical and phylogenetic studies in-
cluding Platydoris angustipes (Morch 1863; Bergh 1877;
Marcus and Marcus 1967; Dorgan et al. 2002) and P.
guarani sp. n. (Marcus 1957; Padula et al. 2012; Alvim
and Pimenta 2013), several external diagnostic features
have been used to distinguish them, but no suggestions
of separating them was ever made. Such features in-
cluded: the rounded and dorsoventrally flattened body,
the foot not exceeding notum, the dorsum covered with
small caryophillidia, the digitiform oral tentacles, the bi-
labiate and longitudinally-notched anterior border of the
foot, and the six tripinnate branchial leaves. Moreover,
the color pattern of the body of P. guarani was deemed
distinctive, with a white ribbon on its edge and dark spots
on both dorsal and ventral parts of the notum (Garcia et
al. 2002; Alvim and Pimenta 2013).

Not all of the differences mentioned above are actually
consistent, but the unique set of distinct features found in
the present study between the Caribbean and Brazilian
specimens, allow the separation in two distinct species.
The main diagnostic features are discussed below.

The rhinophore of P. angustipes has circa 19 lamellae,
while P. guarani has circa 25. However, Dorgan et al.
(2002) reported 25 lamellae for P. angustipes and Alvim
and Pimenta (2013) reported 19-25 lamellae for P. gua-
rani. As such, this possible diagnostic feature should be
studied on a larger sample.

Regarding the circulatory system, the renal vesicle of
P. angustipes has approximately 1/6 of the ventricle size,
while in P. guarani this structure is very large, of about
the same size as the ventricle. Moreover, the nephros-
tome in P. angustipes is readily visible (Fig. 1E), whereas
in P. guarani it 1s not.

Some differences were found in the anterior portion
of the digestive system, particularly in the odontophore
muscles: mt and m2 are very long in P. angustipes (Fig.
2D, E), while those of P. guarani are about half the size
(Fig. 9A, B); m2 bifurcates on its insertion in P. angusti-
pes (Fig. 3C), which is not the case in P. guarani. Two
muscles occur only in P. guarani, namely m7b and m4a
(Fig. 9C, D).

In addition, there are visible differences in the midgut.
In P. angustipes the cecum is circa half the length of the
midgut (Fig. 3A), while in P. guarani it is much shorter,

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14 Lima, P. V. & Simone, L. R. L.: Revision of Platydoris angustipes and description...

about 10% of the midgut (Fig. 8C). The anterior portion
of the intestine of P. guarani is S-shaped (Fig. 8C), while
that of P. angustipes is straight (Fig. 3A).

The posterior end of the radula of P. guarani (Fig. 11A)
is wider than the same region of P. angustipes (Fig. 6A).
In P. guarani, the two outermost lateral teeth are narrower
than in P. angustipes (about half the width; Fig. 11C) and
hook-shaped. The outermost lateral teeth of the radula of
P. angustipes are wide (Fig. 6C), as observed by Dorgan
et al. (2002: fig. 11C), with the two outermost teeth spat-
ulate. The same occurs in P. guarani (Marcus and Marcus
1970), but the two outermost spatulate teeth have shorter
cusps and several denticles (see fig. 121); this can also be
observed in young rows of teeth.

There are also differences in the reproductive system.
In P. angustipes it is very difficult to distinguish the go-
nad from the digestive gland, whereas in P. guarani, the
gonad surrounds the digestive gland, being readily visible
(Fig. 8C). In both species, we could not observe the ac-
cessory gland (contra Marcus 1957; Dorgan et al. 2002;
Alvim and Pimenta 2013).

The most significant difference between P. angusti-
pes and P. guarani is the absence of spines and cuticle in
both the vagina and penis of P. guarani (Fig. 10A, B). An
additional diagnostic feature was given by Dorgan et al.
(2002): P. angustipes has more spines on the inner sur-
face of the penis (even more than what we observed, only
three prominent spines; Fig. 4E).

Furthermore, Platydoris guarani is clearly distinguish-
able from other species of Platydoris by the absence of
spines and cuticle in both vagina and penis, and absence
of the accessory gland. Platydoris guarani resembles P.
carolynae (Dorgan et al. 2002: fig. 29C) in the hook-
shape of outermost teeth.

In conclusion, the most characteristic differences be-
tween the two populations of Platydoris, Brazilian and
Caribbean, reside in the digestive system, especially in
the odontophore, radula and reproductive system. Based
on these findings, Platydoris angustipes (Morch, 1863)
is here restricted as a Caribbean species, while the Bra-
zilian population is described as a new species, Platydo-
ris guarani. The analysis of additional specimens is still
necessary to ascertain which species actually occurs on
Ascension Island.

Acknowledgments

We are very grateful to Tom Schiotte (ZMUC) for
loaning the type material of P. angustipes, to Lara
Guimaraes (MZSP) for SEM examination; to Hilton
Galvao-Filho (MZSP) for comments on an earlier ver-
sion of the manuscript; to Vinicius Padula (UFBA) for
the photos of live specimens of P. guarani. This work
was supported by Conselho Nacional de Desenvolvi-
mento Cientifico e Tecnologico (CNPq, Brazil), proc.
159446/2012-0.

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