Description of a new species of Calliostoma (Gastropoda, Calliostomatidae) from Southeastern Brazil

Abstract Calliostoma tupinamba isa new species from Southeastern Brazil, ranging from southern Rio de Janeiro to northern São Paulo, and found only on coastal islands, on rocks and sessile invertebrates at 3 to 5 meters of depth. Shell and soft part morphology is described here in detail. Calliostoma tupinamba is mainly characterized by a depressed trochoid shell; eight slightly convex whorls; a sharply suprasutural carina starting on the third whorl and forming a peripheral rounded keel; and a whitish, funnel-shaped and deep umbilicus, measuring about 5%–10% of maximum shell width. Calliostoma tupinamba resembles Calliostoma bullisi Clench & Turner, 1960 in shape, but differs from it in being taller and wider, having a smaller umbilicus and lacking a strong and large innermost spiral cord at its base. Finally, an identification key of Brazilian Calliostoma species is presented.


Introduction
The speciose genus Calliostoma Swanson, 1840 has a worldwide distribution, occurring from the intertidal zone to depths of several hundred meters (Clench and Turner 1960). The species are frequently found in association with sessile invertebrates, such as hydrozoans, gorgonians and urchins, and many of them are carnivorous (Perron 1975;Perron and Turner 1978;Quinn 1981;Marshall 1988Marshall , 1995Williams et al. 2010;Dornellas and Simone 2011).
An astounding diversity of Calliostoma species is found in the Western Atlantic: almost 100 species, 18 of which occur in Brazilian waters (Clench and Turner 1960;Quinn 1992;Rosenberg 2009). Calliostoma shells generally have spire typically straight-sided, but may be redounded, and the base ranges from flat to convex, umbilicate or imperforate, sculptured by spiral beaded cords, with a subquadrate aperture and an arched columella. Their ground colors usually are slightly yellowish or brownish, while their secondary coloration consists of white, red or reddish-brown blotches (Hickman and McLean 1990). On anatomical grounds, Calliostoma shows some apparently unique features, such as the presence of an ampulla in females, the reduction or lack of cephalic lappets, the presence of a pseudoproboscis and the intestinal loop placed outside of the haemocoel (Randles 1905;Fretter and Graham 1962;Sá and Coelho 1986;Dornellas and Simone in press;Dornellas personal observation).
A new species of Calliostoma from Southeastern Brazil is here described, with a detailed morpho-anatomical description. An identification key, based on shell characters of fully grown Brazilian Calliostoma species is provided.
Specimens preserved in 70% alcohol were extracted from their shells and dissected under a stereomicroscope. All drawings were made with a camera lucida. For detailed examination of radulae, jaws and protoconch, samples were mounted on stubs, coated with a gold-palladium and observed under a scanning electron microscope. Dimensions for the holotype are given as height X width. Protoconch and shell whorls are counted following Diver (1939) methodology. The list of examined material, housed at MZSP, MNRJ and MOFURG, follows the species description.
Diagnosis. Shell reaching 38 mm in height, with sharply suprasutural carina starting on the third whorl and forming a large peripheral rounded keel. Umbilicus deep, white, funnel-shaped, narrow (5% to 10% of maximum shell width). Base convex.
Description. Shell (Figs 1-9, 16). Attaining 37.6 mm × 38.2 mm; depressed trochoid; 8 whorls, slightly convex. Sharp suprasutural carina starting on third whorl and forming peripheral rounded keel. Basic color of shell pale or tawny brown to pinkishbrown with white and dark red to purple spots and axial flammules, especially on periphery; apex purple; base with numerous white dots on beads. Protoconch (Figs 9, 16) of 0.75 whorls, sculptured with tiny pustules. Transition to teleoconch marked by a weak terminal varix. Teleoconch sculptured by beaded spiral cords (beads crowded and rounded), with one or two smaller intercalary beaded spiral cords between, without a pattern. About 20 beaded cords on the last whorl. Cords on the body whorls becoming remarkably narrower towards periphery. First three whorls of teleoconch with weak axial riblets. First whorl with about 15 axial riblets and two weakly spiral cords that produce reticulate sculpture at their intersections (Fig. 16). The spiral cords become stronger starting on the second whorl. Base convex (flattened in juveniles), with about 15 cords between umbilicus and periphery. Cords equal in size and smoother than that of the teleoconch. Spire angle ~80º. Aperture subquadrate, with base round in adults but flat in juveniles; outer lip at ~55º angle from base. Columella truncated, heavily arched, thickened, white, terminating in a rounded denticle. Umbilicus deep, white, funnel-shaped, 5% to 10% of maximum shell width.
Head-foot (Figs 29-30, 32). Total length two whorls. Head rounded located approximately at anterior end of head-foot. Snout reddish, wide, cylindrical; distal end slightly wider than base; dorsal surface papillated, with short, rounded and white papillae; distal surface folded. Outer lips with pseudoproboscis ( Fig. 32: pb). Mouth circular, located in middle of ventral surface of snout. Cephalic lappets absent. Cephalic tentacles usually twice larger than snout, sometimes asymmetrical, reddish, dorsoventrally flattened, grooved, narrowing gradually up to lightly pointed tip. Ommatophores located at outer base of cephalic tentacles, ~1/3 of tentacles' length. Eyes dark and round, at tip of ommatophores.
Foot thick, occupying ~3/4 of total head-foot length; reddish colored; dorsal region covered by numerous white papillae. Epipodium (  from each other, symmetrical on both sides, becoming shorter towards posterior end. Epipodial sense organ present at base of each tentacle, indistinguishable from the foot papillae on the lateral sides of the foot. Pair of columellar muscles thick, ~¼ whorl, fused with each other in median line.
Mantle organs (Fig. 31). Pallial cavity ~3/4 whorl. Mantle border (mb) thick, white with irregular band of brown; anterior end papillated, occupying ~1/3 of mantle border. Gill located on left side of pallial cavity, occupying almost its entire length, projecting anteriorly and sustained by gill rod (sg) and suspensory membrane. Anterior end of gill narrow, with pointed tip, gradually increasing towards narrow posterior end. Osphradium rounded located at base of gill road. Afferent gill vessel ~2/3 of gill's length, arising from transverse pallial vessel, running in distal region of central axis of gill. Transverse pallial vessel arising off from left nephrostome, discharging in afferent gill vessel. Ctenidial vein (cv) (= efferent gill) vessel about 1/3 longer than afferent vessel, running in basal region of gill central axis; its posterior 1/9 free from gill filaments, lying parallel, at left from afferent vessel up to pericardium. Hypobranchial gland (hg) on both sides of rectum; more developed on left side. Rectum ~¼ of pallial cavity width, sigmoid on posterior region under kidneys, gradually straightening towards the anus. Anus siphoned, smaller than rectum's width; pleated, short free end, located on anterior right side of pallial cavity. Kidneys posteriorly located in pallial cavity, ~1/3 of rectum's length.
Visceral mass. Not studied. Circulatory and excretory systems (Fig. 31). Pericardium (pc) located between pallial cavity and visceral mass, immediately posterior to kidneys, close to median line; its left side receiving ctenidial vein and right side receiving right pallial vein.
Papillary sac (ps) of left kidney ~1/3 of rectum's length; oval, with wide base; gradually narrowing towards anterior, ending at left of nephrostome; inner wall with numerous thin and long papillae projecting inward from all surfaces. Right kidney (rk) divided in two regions: anterior region hollow, a tube ~1/3 of rectum's length and ~1/2 width of papillary sac in male; in female called ampulla (ap), large, oval, hollow, filled by mucus, ~3/4 larger than papillary sac; kidney expanding ventrally, covering right half of surface of adjacent visceral hump; posterior region spreading around visceral mass immediately beneath mantle, encircling inner surface of columellar muscle.
Digestive system (32)(33)(34)(35)(36)(37)(38). Oral tube ~1/2 of odontophore in length and width; walls with circular muscles. Jaws triangular in shape, dark brown; very long denticles on anterior end, projecting in tufts (Figs 17-19). Pair of dorsal folds starting posteriorly to jaws (Fig. 33: dc), each dorsal fold bending, partially overlapping, forming two slits; upper slit rounded, ventral slit triangular. Series of transverse muscles separating outer surface of esophagus from odontophore. Odontophore about twice longer than snout. Odontophore muscles (Figs 34-38): m1, series of small muscles connecting buccal mass with adjacent inner surface of snout and haemocoel; m1d, pair of small dorsal retractors muscles, originating in postero-lateral region of mouth sphincter (Figs 35-36: mc), inserting itself in antero-lateral edge of posterior cartilage; m1v, pair of small ventral protractors muscles of odontophore, originating on surface central of oral tube, running posteriorly away from each other, inserting in postero-ventral region of odontophore, in median surface of posterior cartilages; m2a, anterior retractor muscles of odontophore, originating in antero-lateral surface of anterior cartilages and inserting in hemocelic lateral walls; m2b, posterior retractor muscles of odontophore, originating in lateral surface of anterior cartilages, posterior to m2a, inserting in haemocelic lateral walls; m4, broad pair of dorsal tensor muscles of radula, subradular membrane, originating partly in anterior cartilages, along their ventral surfaces at some distance from median line, and partly in posterior cartilages, in their posterior, lateral surfaces, surrounding anterior cartilages lateral, ventral surfaces, and inserting along subradular membrane, in its dorsal region exposed inside buccal cavity, with portion in radular ribbon in its region preceding buccal cavity; m5, pair of large accessory dorsal tensor muscles of radula, originating in ventral surface of posterior cartilages, running towards median dorsal region, subsequently running anteriorly, inserting in in posterior region of radular ribbon; m6, horizontal muscle, uniting both anterior cartilages almost along entire ventral edge, except for short posterior region, in their external surface; m7a, very long, thick pair of muscles, originating in hemocelic ventral surface, running dorsally, inserting in radular sac, posteriorly to insertion of m5; m7b, pair of muscles originating in lateral inside wall of radular sac, dividing into three thin beam muscles, two of them inserting in posterior cartilage and other entering through m10l; m8, pair of broad approximator muscles of cartilages, originating in anterior cartilages, along its lateral surface, posterior to insertion of jm, running posterior, decreasing gradually, inserting in middle region of anterior surface of posterior cartilages; m10, pair of broad ventral protractor muscles of odontophore, originating from ventral region of mouth and buccal sphincter, running posteriorly, inserting in anterior region of posterior cartilage just ventral to m8 insertion; m10l, pair of broad lateral protractor muscles of odontophore, originating from lateral oral cavity, inserting in outside of anterior region of posterior cartilage; m11, two pairs of ventral tensor muscles of radula, originating in middle region of ventral surface of posterior cartilage, one separated from other by distance equivalent to their width, running anteriorly covering m6, anterior cartilage's ventral surface, becoming wider in anterior region, inserting in subradular membrane distal edge; m11a, very long, thin pair of oblique tensor muscles of radula, originating in hemocelic anterior surface near pleural ganglia, running dorsally through between anterior edge of anterior cartilages, inserting in subradular membrane distal edge; jm, jaw muscles, originating gradually from dorsal surface of oral tube, close to median line, running divergently towards posterior and sides, inserting themselves in latero-ventral surface of the anterior cartilage; jma, dorsal jaw pair muscles, originating in anterodorsal region of anterior cartilage, running dorsally for short distance, surrounding oral cavity; ml, two pairs of wide and thick lateral muscles, originating in hemocelic lateral wall, running straightly forward, internal through the side wall of buccal cavity, inserting themselves in median line of lateral surface of anterior cartilage.
Salivary gland indistinguishable from dorsal region of buccal cavity; salivary aperture in mid-dorsal region of buccal cavity, on dorsal folds. Four dorsal fold channels; two of them are a continuation of dorsal folds in mid esophagus (Fig. 33: df); ventral food channel continuing ventral esophageal fold; esophageal valve ( Fig. 33: ev) located on ventral food channel; mid esophagus with two esophageal folds, a higher ventral fold and right dorsal fold. Posterior esophagus narrow; inner surface with some longitudinal, narrow folds. Esophagus insertion and stomach not observed. Rectum, anus described above (pallial organs).
Genital system: not observed due to damage during extraction of soft parts.
Central nervous system (Figs 34-35): Nerve ring surrounding anterior half of buccal mass. Cerebral ganglia (Fig. 35: ce) rounded, located on lateral region of buccal  mass and occupying ~1/3 of it; commissure thick, long; both dorsoventrally flattened cerebropleural and cerebropedal connectives ( Fig. 35: cp, ccn) long and thin, originating in anterior region of cerebral ganglia, running ventrally and back to pedal and pleural ganglia. Cerebropleural connective twice as thick as cerebropedal. Labial ganglia ( Fig. 35: lg) very small, ~1/5 of cerebral ganglia, located in ventro-lateral region of buccal mass, anteriorly to cerebral ganglia; linked to cerebral ganglia by short cerebrolabial connective. Buccal ganglia about same size as labia ganglia; located posteriorly to cerebral ganglia; connected united to cerebral ganglia by buccolabial connective; buccal commissure ( Fig. 34: bc) thick, lying dorsally to radular sac.
Distribution. From southern Rio de Janeiro to northern São Paulo, 23° to 24°S, 44° to 45°W, only on coastal islands (from Alcatrazes Archipelago to Jorge Grego Island).

Discussion
The overall shell shape of Calliostoma tupinamba closely resembles C. bullisi Clench & Turner, 1960 from northern Brazil. It differs in being taller and wider: the holotype of C. bullisi (Figs 10-12) is a 2 cm tall, has a convex base and a well-developed and rounded peripheral keel, indicating an adult stage, while all examined specimens of C. tupinamba of 2 cm are juveniles, showing a flattened base and a less developed periph-eral keel (Fig. 7). The base of the shell of C. bullisi has a strongly and larger innermost spiral cord (Fig. 12). When it is present in C. tupinamba, this cord is half the size from that of C. bullisi. The umbilicus of C. tupinamba is much narrower, occupying only 5% to 10% of the maximum shell width, while in C. bullisi the umbilicus occupies 20%. Unfortunately, there is no reference in the literature regarding the soft parts' anatomy of C. bullisi: Clench and Turner (1960) described only the head-foot morphology, but without illustration of it differentiating apparently by having uniform red brown tentacle while C. tupinamba has a thin darker longitudinal line in median dorsal region of tentacle. The radula of the holotype of C. bullisi was illustrated with a drawing by Clench and Turner (1960: 5, pl. 5, fig. 1). The radula of C. tupinamba differs from C. bullisi by having slender rachidian and lateral shafts. The protoconch sculpture with a honeycomb pattern is diagnosed for calliostomatids (Hickman and McLean 1990). Marshall (1995) also observed this pattern in an excellent revision of calliostomatids from New Caledonia. Calliostoma tupinamba has not such a pattern, which is also absent in C. torrei Clench & Aguayo, 1940(following Harasewych 2006, C. depictum Dall, 1927 andC. adspersum (Philippi, 1851) (Dornellas and Simone in press). As protoconch sculpture descriptions are lacking in major revisions of the fauna of the western Atlantic (see Clench and Turner 1960;Quinn 1992) it is hard to know whether the honeycomb pattern is present in the western Atlantic Calliostoma.
Calliostoma tupinamba differs from C. hassler Clench & Aguayo, 1939 (Figs 13-15) from Southeastern Brazil by being wider, having spiral cords with coarser beads and a uniform pattern of mottled color. Anatomically, the snout is more papillated on the dorsal surface in C. tupinamba. The rachidian tooth of C. tupinamba has a rounded base, while the tooth of C. hassler is triangular. Moreover, there are differences in the odontophore's muscles: Calliostoma hassler has not a jma pair and a thicker ml pair (Dornellas and Simone in press).
In a revision of the Western Atlantic's Calliostoma, Clench & Turner (1960) allocated some species such as C. jujubinum, C. bullisi in the subgenus Elmerlinia. This taxon is characterized by the triangular shape of the jaws, with denticles projecting in tufts on the distal edge, and by the two lateromarginal plates in the radula. The same pattern is observed in C. tupinamba and C. hassler and, therefore, it seems to be closely related with species of Elmerlinia. Interspaces of first whorls lacking axial sculpture, subsequent whorls with low folds. Height up to 13 mm (Fig. 42)  Circumbasal cords weak to strong; interspaces between peripheral keels concave (Fig. 45)  Whorl periphery with two spiral cords (Fig. 46) ...C. jucundum (Gould, 1849) 14 (13) Three reddish brown bands encircling each whorl; apex of shell deep purple (Fig. 47)