Paradentalium infractum ( Odhner, 1931 )

Caetano, Carlos Henrique Soares, Scarabino, Victor & Absalão, Ricardo Silva, 2006, Scaphopoda (Mollusca) from the Brazilian continental shelf and upper slope (13 º to 21 ºS) with descriptions of two new species of the genus Cadulus Philippi, 1844, Zootaxa 1267, pp. 1-47 : 12-13

Paradentalium infractum ( Odhner, 1931) n.comb.

Figs. 16–19

+ Dentalium infractum Odhner 1931: 1 , pl. 1, figs. 1–3, 8, 10, 12, pl. 2, figs. 15–17, 22, 23. + Dentalium (Dentalium) infractum: Scarabino 1973: 195 , pl. 1, figs. 2, 2a.

+ Dentalium (Antalis) infractum: Penna­Neme 1974: 110 , figs. 2, 4, 5, 6.

+ Dentalium (Antalis) elegantulum Penna­Neme 1974: 108 , figs. 1, 3.

+ Antalis infractum: Scarabino 1985: 198 , pl. 72, fig. 1013; 1994: 306, pl. 106, fig. 1501. + Antalis infracta: Steiner and Kabat 2001: 440 ; 2004: 602.

Type material

Holotype SMNH 1554; Paratypes SMNH 6337, 12 lv, SMNH 6338, 4 dd.

Type locality

"Küste von [Coast of] Uruguay ", 33°00’S – 51°10’W, 80 m (by original designation) but corrected to South Brazil by Scarabino (1973).

Diagnosis

Shell up to 49 mm long, slender, slightly curved, white to yellowish, polished, shining. Six thin primary ribs on posterior half of the shell, dorsal one larger than the others. Anterior half smooth. Secondary ribs present, number variable. Intercostals spaces straight to convex. Apical section hexagonal, oral section circular.

Material examined

Holotype MZUSP 18699; Paratypes MZUSP 18700, 4 dd; MZUSP 18702, 2 dd, of D. elegantulum ; IBUFRJ 7900, sta AV10,1 dd; IBUFRJ 8024, sta D1, 1 lv; IBUFRJ 7981, sta D4, 1 dd; IBUFRJ 14240, sta Y5, 7 lv, 34 dd; IBUFRJ 14241, sta C27, 3 lv, 8 dd; IBUFRJ 14242, sta 27, 2 dd; IBUFRJ 14243, sta R2#1, 12 dd; IBUFRJ 14244, sta R3#2, 2 dd; MORG 13864, off São Luiz, Maranhão, 33 m, 1 dd.

Distribution

Brazil: Maranhão (this study), Alagoas, Bahia to Rio Grande do Sul ( Odhner 1931; Penna­Neme 1974; Scarabino 1973, 1975, 1985, 1994); Uruguay ( Scarabino 1973). Living 40–190 m, shells 5 to 269 m (this study).

Remarks

Odhner (1931) described the species from off Uruguay but, as observed by Scarabino (1973), the latitude given by the author corresponds, in fact, to South Brazil. Penna­Neme (1974) identified specimen number MNRJ 3646 as one of the paratypes of D. elegantulum , but it could not be found in MNRJ.

Antalis cerata ( Dall, 1881) and Paradentalium disparile ( Orbigny, 1853) are the most similar species to P. infractum in the western Atlantic. Paradentalium infractum and A.

cerata shared the pattern of alternating sculptured and smooth portions along the shell extent but the latter showns an apex with nine to twelve ribs while P. infractum shown a hexagonal apical section. Additionally, A. cerata has microscopic reticulation in the intercostals spaces (see Fig. 22 ). The apex is composed of six ribs in both Paradentalium disparile and P. infractum , but in P. d i s p a r i l e the secondary ribs are more numerous and strongest occurring over the entire shell ( P. disparile has no smooth portion).

Figures

FIGURES 1 – 19. Genus Dentalium and Paradentalium. (1 – 5) Dentalium laqueatum, (1) IBUFRJ 14233, 40 mm, (2 – 5) IBUFRJ 14238, 27 mm; (6 – 10) Paradentalium gouldii, (6) Paralectotype MCZ 7707, (7 – 10) IBUFRJ 10796, 10 mm; (11 – 15) Paradentalium disparile, (11 – 13) IBUFRJ 7744, 36 mm, (14 – 15) other specimen from the same lot exibiting the apical pipe, 29 mm; (16 – 19) Paradentalium infractum, IBUFRJ 14240, 45 mm. Scale bar = 100 m.

FIGURES 20 – 38. Genus Antalis and Coccodentalium. (20 – 22) Antalis cerata, IBUFRJ 14253, 27 mm; (23 – 28) Antalis circumcincta, (23) Lectotype BMNH 1887.2. 9.30, 48 mm, (24) Paralectotype BMNH 1887.2. 9.29, 46 mm, (25 – 28) IBUFRJ 14302, 48 mm; (29 – 32) Antalis taphria, IBUFRJ 14254, 16 mm; (33 – 38) Coccodentalium carduus, IBUFRJ 14245, 89 mm. Scale bar = 100 m.