Crepidula intratesta, Simone, 2006

Simone, Luiz Ricardo L., 2006, Morphological and phylogenetic study of the Western Atlantic Crepidula plana complex (Caenogastropoda, Calyptraeidae), with description of three new species from Brazil, Zootaxa 1112 (1), pp. 1-64 : 21-23

Crepidula intratesta , new species

(Figs. 13–15, 112)

Crepidula plana: Rios 1985: 59 (pl. 21, fig. 267); Rios 1994: 71 (pl. 24, fig. 272). (Non Say 1822.)

Crepidula (Ianacus) plana: Rios 1970: 56 ; 1975: 65 (pl. 17, fig. 260); Oliveira et al. 1981: 112. (Non Say 1822.)

Crepidula aff. plana: Simone 2002 (figs. 4, 7, 60–62, 119–140).

Types: Holotype ♀ MZSP 30791 (19.5 by 14.8 mm) . Paratypes: BRAZIL. Espírito

Santo; off Vitória, MNRJ 8989, 5 shells (P.M. Costa col. otter trawl, 2001). RIO DE JANEIRO; Rio de Janeiro, Governador Island, Centro de Instrução da Marinha, MNRJ 2338, 1♀ (Adolfo Emigdio col. Iii/1957). São Paulo; off Ubatuba ( Integrated Project IOUSP, R.V. Veliger II col.) , 23°30'S 44°54'W, 42m depth, MZSP 30790 , 5 specimens (Sta. 26, 21/iv/1986) ; 23°25'S 44°52'W, 21 m depth, MZSP 30803 , 13 specimens (Sta. 27, 21/iv/1986) ; 23°29'S 44°52'W, 38 m depth, MZSP 30798 , 2 specimens (Sta. 8, 28/x/1985) ; 23°33'S 44°50.5'W, 43 m depth, MZSP 30799 , 2♀ (Sta. 7, 28/x/1985) ; 23°34'S 44°48'W, 44 m depth, MZSP 30801 , 4 specimens (Sta. 17, 22/i/1986) ; 23°34'S 45°06'W, 21 m depth, MZSP 30802 , 24 specimens (Sta. 12, 20/i/1986) , 20 m depth, MZSP 30800 , 1 specimen (Sta. 39, 21/x/1986) ; 23°34'S 45°07'W, 20 m depth, MZSP 30797 , 2 specimens (Sta. 21, 18/iv/1986) ; 23°38'S 44°49'W, 47 m depth, MZSP 30795 , 1♀ (Sta. 16, 22/i/1986) ; 23°38'S 45°14'W, 16 m depth, MZSP 30805 , 1 specimen (Sta. 42, 22/x/1986) ; 23°39'S 45°04'W, 36m depth, MZSP 30792 , 2♂ (Sta. 11, 20/i/1986) ; 23°44'S 45°00'W, 42 m depth, MZSP 30796 , 2♀ (Sta. 37, 21/x/1986) ; 23°44'S 45°15'W, 32 m depth, MZSP 30804 , 10♀, MZSP 36325 , 2♀ (sta. 5, 27/x/1985) ; 23°47'S 45°10'W, 35 m depth, MZSP 30793 , 2♂, 1♀ (Sta. 14, 21/i/1986) . Rio Grande do Sul, off Albardão , 33°32'S 52°18'W, 35 m depth, MZSP 19034 , 10♀ ( GEDIP­RS, R. V. W. Besnard sta. 571, 13/iii/1969) .

Type locality: BRAZIL; São Paulo; off Ubatuba , 23°29'S 44°52'W, 38 m depth (Integrated Project IOUSP, R.V. Veliger II, Sta. 8, 28/x/1985) .

A complete conchological and anatomical description of this species is provided elsewhere ( Simone 2002). In present paper only a formal description for naming this species is presented.

Description: Shell (Figs. 13–15): Medium to large size (up to 40 mm), color white, periostracum deciduous. Dorsal surface plane to concave, arched, opaque. Sculpture lacking, except for concentric, low, narrow somewhat uniform undulations and growth lines. Protoconch 1 whorl, inlaid, located approximately in center of posterior edge. Borders sharp, fragile, with weak remains of pale brown, hairy periostracum. Ventral surface smooth, glossy, white. Septum triangular, protruding ventrally; lateral edges almost straight, at some distance from shell edges; posterior end normally with a shallow concavity and at some distance from shell posterior end. Septum anterior free edge concave, presenting a shallow central notch from which edges diverge gradually towards anterior and lateral, somewhat straight; left insertion in shell simple; right insertion marked by a somewhat deep and narrow notch. No clear muscle scar.

Inner anatomy: Already described in Simone (2002). The some complements follows. 1) Odontophore muscle m12, a small pair of muscles, originating in odontophore cartilages in a small portion by side of m6 (horizontal muscle) anterior region, running free towards ventral and lateral, inserting in short distance in subradular membrane inner surface. 2) Female genital papilla somewhat tall, in posterior surface a pair of broad folds running longitudinally close from each other, between both a narrow furrow, each one surrounding distal, narrow genital pore; an additional left­dorsal, longitudinal, low fold, originating gradually in papilla base, disappearing gradually at some distance lateral from genital pore (Fig. 112).

Habitat: Almost invariably within empty gastropod (bivalve sometimes) shells, from intertidal to 73 m depth.

Distribution: Central and Southeast coast of Brazil (Bahia to Rio Grande do Sul).

Measurements of shells (in mm): MZSP 36325: 1) 18.4 by 14.0, 2) 19.1 by 15.3; MZSP 30795: 24.1 by 18.0; MZSP 30790: 27.3 by 20.0. Holotype see type list.

Etymology: The specific epithet refers on the living habit inside empty shells, being intra meaning inside, and testa meaning shell from the Latin.

Material examined: Types and those listed in Simone (2002).

Discussion: Crepidula intratesta has been considered as the Brazilian occurrence of C. plana . However, based on the anatomical difference with the C. plana specimens collected from the neotype locality, and further arguments given by Collin (2000), the specific separation becomes necessary. This description was considered premature in by Simone (2002), but is provided here. A more complete morphological differentiation is given in the section of discussion of characters. However, the more outstanding differences are the C. intratesta longer osphradium, with more filaments; endostyle simple (not divided along its length); kidney with larger hollow chamber, lacking solid dorsal lobe; the thinness of the peri­oral and jaw muscles (mc); the presence of an auxiliary ventral tensor muscle of the radula (m7a); salivary gland very shorter, forming a single mass (instead of being coiled); a different arrangement of gastric inner folds; the penis with shorter terminal papilla; pallial oviduct with fewer seminal receptacles; papilla of female pore with different folds (Figs. 66, 112).

Although all species of the “ C. plana complex” potentially can show a concave dorsal surface, this apparently is rare. I have not seen any specimen with this shell morphology, except some specimens of C. plana . Crepidula intratesta almost invariably has the concave dorsal surface, which easily differentiate it from the other species. This shell morphology has the shell septum protruding by the ventral shell surface. It is undoubtedly a consequence of the habitat inside empty shells (mostly gastropods).

Further anatomical discussion and distinction is provided by Simone (2002) and herein, in the following section. However, it is interesting to establish that the anatomical difference between C. intratesta , and particularly with C. protea , is relatively small. The differences remain in the conchological features and in developmental attributes ( C. protea most probably is not a protandric hermaphrodite, but a dioic).