Vol. 99 (2-3) 

April 29, 1985 

THE NAUTILUS 45 

ARENE FLEXISPINA. A NEW SPECIES (GASTROPODA: LIOTIIDAE) 

FROM OFF EASTERN BRAZIL 

Jose Henrique N. Leal 1 and Arnaldo C. dos Santos Coelho 

Setor de Malacologia 2 - Museu National 

20.942 - Rio de Janeiro, RJ - Brasil 

Seven species of the genus Arene H. & A. 
Adams, 1854 are already known from the Brazil- 
ian coast: Arene tricarinata (Stearns, 1872), A. 
briareus (Dall, 1881), A. variabilis (Dall, 1889), 
A. bairdii (Dall, 1889), A. brasiliana (Dall, 
1927), A. riisei Rehder, 1943 (Abbott, 1974; 
Rios, 1975) and A. notialis Marini, 1975 (Marini, 
1975). The present description is based on speci- 
mens obtained through bottom sampling (van 
Veen and Petersen grabs) between 54 and 82 
meter depth during the GEOMAR X cruise 
undertaken by the Brazilian Navy research 
vessel "N.Oc. Almirante Camara" along the 
eastern coast of Brazil, in the period of 01-11 
June 1978. Sampled substrate in the three sta- 
tions where the species was found consisted of 
fragments of calcareous algae and calcareous 
gravel. Although soft parts are not preserved, 
thus making difficult a more accurate taxonomic 
characterization, shell features are markedly 
distinct. 

Arene flexispina new species 
(Figs. 1-3) 
Description: Shell small, solid, trochoid in 
shape, reddish brown, with spiral rows and 
spines of lighter color. Ratio height/width of the 
shell higher in adults than in younger speci- 
mens. Whorls 5V2, the first IV2 comprising the 
protoconch, white and smooth, lower than the 
subsequent whorl. Teleoconch whorls with 2 
larger peripheral spiral rows of 10 or 11 large, 
fluted spines spirally raised and imbricated. 
Narrower row 1-2 subsutural, one intermediate 
(between the 2 larger) and one immediately 
above the subsequent whorl, with numerous im- 
bricated scale-like spines, smaller than those in 
the 2 larger rows. Finely incised axial lines on 
entire shell microscopic and crowded. Suture 

'Present address: B.L.R., Rosenstiel School of Marine and 
Atmospheric Science, 4600 Rickenbacker Causeway, Miami, 
FL 33149 
Contribution no. 46 

channeled, clearly defined. Body whorl rounded, 
with wider spiral cords; spines in the 2 larger 
cords triangular, bent outwards and sharply 
pointed in apical view; spines number the same 
as in the spire. Base with 4 or 5 well-separated 
beaded spiral cords; beads almost imperceptible 
in worn specimens. Cord bordering the umbili- 
cus the same size or only slightly larger than the 
other basal cords (younger specimens). Um- 
bilicus wide, deep and twisted, with fine axial 
lines internally. One or two cords entering the 
umbilicus in younger shells, absent in mature 
specimens. Aperture whitish, oblique. Outer lip 
thin, with crenulations corresponding to the ex- 
ternal spiral ornamentation. Operculum round, 
multispiral, with small radial lines giving beaded 
aspect to its calcareous external surface. 
Attachment side horny and convex. 

Material examined: GEOMAR X station 048, 
40 km off Ponta de Corumbau, Bahia, Brazil 
(16°56'30"S, 38°39'30"W), 80 m depth, "N.Oc. 
Almirante Camara" col. 09 June 1978, Holotype, 
Museu National, Rio de Janeiro, Brazil (Col.Mol. 
MN 5352), height 6.4 mm, width 6.7 mm; Para- 
type 1, United States National Museum, Wash- 
ington, D.C. (USNM 820786), height 5.4 mm, 
width 6.2 mm; Paratype 2 (Col.Mol.MN 5353), 
height 4.7 mm, width 5.4 mm; Paratype 3, 
Museu Oceanografico, Fundacao Universidade 
do Rio Grande, Rio Grande, Brazil (MORG 
22807), height 3.5 mm, width 4.5 mm; Paratype 
4 (USNM 820786A), height 3.4 mm, width 4.3 
mm; Paratype 5 (MORG 22808), height 3.2 mm, 
width 4.3 mm; GEOMAR X station 038, 170 km 
off Conceicao da Barra, Espirito Santo, Brazil 
(18°49'00"S, 37°52'00"W), 54 m depth, "N.Oc. 
Almirante Camara" col. 07 June 1978, Paratype 
6 (MORG 22619), height 2.0 mm, width 3.0 mm; 
GEOMAR X station 047, 120 km off Abrolhos 
Reef, Bahia, Brazil (17°44'00"S, 37°21'00"W), 54 
m depth, "N.Oc. Almirante Camara" col. 08 
June 1978, Paratype 7 (Col.Mol.MN 5354), 
height 1.4 mm, width 2.4 mm. 

46 THE NAUTILUS 

April 29, 1985 

Vol. 99(2-3) 

FIGS. 1-3. Arene flexispina n. sp. 1 and 2, Apertural and 
ventral views of the holotype, Col.Mol.MN 5352, 40 km off 
de Corumbau, Bahia State, Brazil. Scale bar=2 mm. 
.'!. Apertural view with operculum of the paratype >'<. MORG 
Vol. 99(2-3) 

April 29, 1985 

THE NAUTILUS 47 

It was observed from the shell measures of the 
8 examined specimens of A. Jlexispina that the 
ratio height/width increases as the shell grows, 
suggesting a pattern of allometrie growth (Fig. 
5), probably a consequence of a gradual altera- 
tion in the angle of coiling in the species. 

A rene Jlexispina appears to be related to A. 
briareus from the Caribbean and tropical west- 
ern Atlantic, according to the original descrip- 
tion (Dall, 1881:52), and later illustration by the 
same author (Dall, 1889: pi. 24, figs. 5, 5a), and 
by comparison of specimens (Col.Mol.MN 5390; 
Morg 14.969), mainly by its elevated spire and 
spinose ornamentation. A. jlexispina differs, 
however, by its darker color, two obviously 
larger cords on body whorl, which are all about 
the same size or only a little larger than the re- 
maining in briareus; ornamentation of the spiral 
cords consisting in about 11 large fluted spines, 
instead of about 40 small spines in briareus; a 
well differentiated ridge or cord around the um- 
bilicus and a nodulose spiral ridge inside it in 
briareus, not present in Jlexispina; outer lip 
thicker in briareus. 

Arene notialis from off southeastern Brazil 
differs by its whitish color, lower spire, about 21 

width (mm) 

FIG. 5. Allometrie shell growth in Arene jlexispina n. sp.; 
sketches illustrate the shape of shells at three points on the 
curve: a) Paratype 7, Col.Mol.MN 5354, height 1.4 mm, 
width 2.4mm; b) Paratype 3. MORG 22807, height 3.5 mm, 
width 4.5 mm; c) Holotype. Col.Mol.MN 5352, height 6.4 
mm, width 6.7 mm. Scale bars= 1 mm. 

nodules (not spines) on spiral cords in the body 
whorl, 8 joined strongly beaded basal spiral 
cords instead of 5 separated cords in Jlexispina; 
umbilicus smaller and straight, bordered by a 
larger basal cord and outer lip thicker in 
notialis, according to Marini (1975) and material 
examined of A. notialis from off Guarapari, 
Espirito Santo, Brazil, "N.Oc. Almirante 
Saldanha" col. September 1968, 80 m depth, 
Col.Mol.MN 4862, two specimens. 

Acknowledgments 

We are indebted to Dr. Donald R. Moore from 
the Rosenstiel School of Marine and Atmos- 
pheric Science, Miami, for the critical review of 
the manuscript, to the staff at Departamento de 
Hidrografia e Navegacao, Ministerio da 
Marinha, Brazil, for providing the adequate con- 
ditions to the obtention of the material exa- 
mined, during the GEOMAR X cruise, to Prof. 
Eliezer de C. Rios, Museu Oceanografico, Rio 
Grande, Brazil, who made available part of the 
studied material and to Mr. Raul Garcia, Rio de 
Janeiro, Brazil, for the drawings of Arene Jlex- 
ispina. 

LITERATURE CITED 

Abbott, R. T. 1974. American Seashells (2nd Edition). Van 
Nostrand-Reinhold, New York, 663 pp. 

Dall, W. H. 1881. Reports on the Results of Dredging, under 
the Supervision of Alexander Agassiz, in the Gulf of 
Mexico, and in the Caribbean Sea, 1877-79, by the United 
States Coast Survey Steamer "Blake", . . . XV. Prelimi- 
nary Report on the Mollusca. Bull. Mus. Comp. Zooi. 
Harvard Univ., Cambridge 12(6):171-318, pis. 1-9. 

1889. Reports on the Results of Dredging, under 

the Supervision of Alexander Agassiz, in the Gulf of 
Mexico (1877-78) and in the Caribbean Sea (1879-80), by 
the U.S. Coast Survey Steamer "Blake", . . . XXIX. - 
Report on the Mollusca. Part II. - Gastropoda and Scapho- 
poda. Bull. Mus. Comp. Zool. Harvard Univ., Cambridge 
18:1-492. 31 pis. 

Keen, A. M. 1971. Sea Shells of Tropical West America. 
Stanford University Press, Stanford, 1064 pp. 

Marini, A. C. 1975. Sobre duas especies novas de micro- 
moluscos (Trochacea: Turbinidae; Liotiidae) da costa 
brasileira. Pap. Ainil. Zool. St. Paulo 29(5):31-34, 2 pis. 

Olsson, A. A. and A. Harbison. 1953. Pliocene Mollusca of 
Southern Florida, with special reference to those from 
North Saint Petersburg with special chapters on Turridae 
by Williams G. Fargo and Vitrinellidae and Fresh-water 
Mollusks by Henry A. Pilsbry. Acad. Nat. Sci. Philad.. 
Monog. 8:1-457, 65 pis. 

Rios, E. C. 1975. Brazilian Marine Mollusks Iconography: 
Fundacao Universidade do Rio Grande, Rio Grande, 
331 pp., 91 pis.