Itaborahia lamegoi Maury, 1935

Salvador, Rodrigo Brincalepe & Simone, Luiz Ricardo Lopes De, 2013, Taxonomic Revision Of The Fossil Pulmonate Mollusks Of Itaboraí Basin (Paleocene), Brazil, Papéis Avulsos de Zoologia 53 (2), pp. 5-46 : 5-46

Itaborahia lamegoi Maury, 1935

( Figs. 43-50 )

Itaborahia lamegoi Maury, 1935: 10 (figs. 6, 7); Oliveira, 1936: 5; Paula Couto, 1949: 11; Trindade, 1956: 13 (pl. 2, figs. 1b, 2b); Magalhães & Mezzalira, 1953: 220 (pl. 64, fig. 258); Parodiz, 1969: 183 (pl. 19, fig. 13); Breure, 1979: 137; Bergqvist et al., 2006: 58 (fig. 68).

Itaborahya lamegoi (error): Mezzalira, 1946: 18.

Bulimulus ? (Itaborahia) lamegoi : Zilch in Wenz, 1959-60: 485, (fig. 1706).

Bulimulus lamegoi : Brito, 1967: 17 (pl. 2, fig. 3); Palma & Brito, 1974: 394 (pl. 1, fig. 1); Simone & Mezzalira, 1994: 51 (pl. 15, fig. 422); Rodrigues & Fonseca, 2007: 253.

Bulimulus sommeri Palma & Brito, 1974: 396 (pl. 2, fig. 3, 5); Breure, 1979: 137; Simone & Mezzalira, 1994: 50 (pl. 15, fig. 423); Bergqvist et al., 2006: 57 (fig. 65).

Holotype: AMNH 24240 (examined; Figs. 48-49 ).

Type Locality: Limestones of Parque Paleontológico de São José de Itaboraí, Rio de Janeiro, Brazil. Park’s center coordinates: 22°50’20”S, 42°52’30”W .

Geographic and stratigraphic occurrence: Known only from the type locality: Sequences S1 and S2 ( Medeiros & Bergqvist, 1999; Bergqvist et al., 2006).

Age : Tertiary, Middle Paleocene.

Etymology: Species dedicated to its collector, Dr. Alberto R. Lamego (Serviço Geológico e Mineralógico do Brasil).

Diagnosis: Shell fusiform. Spire apex sharply acuminated, with somewhat concave outline. Aperture prosocline. Peristome reflected, incomplete (absent in parietal region). Columellar fold in the uppermost part of the columellar region (next to parietal region). Umbilicus imperforated.

Re-Description: Shell large, fusiform. Greatest width on body whorl; width ~½ shell length. Spire angle ~50°. Profile of whorls slightly convex. Spire apex sharply acuminated, with somewhat concave outline. Suture well-marked, linear, slightly oblique (diagonal) to columellar axis. Protoconch apparently smooth; transition to teleoconch unclear. Shell smooth, except for growth lines. Aperture large, sub-oval, prosocline; ~½ shell length. Peristome reflected, incomplete (absent in parietal region). Columellar fold in uppermost part of columellar region (next to parietal region), extending itself towards shell interior. Body whorl ~⅔ shell length. Umbilicus imperforated.

Measures (in mm): Holotype: 6 or 7 whorls (shell apex broken); H = 31.4; D = 15.1; S = 16.7; h = 15.9; d = 9.9. Mean (n = 7): 7 whorls; H = 30.6 ± 4.5 (max 34.6; min 25.7); D = 13.3 ± 1.8 (max 16.5;

min 11.8); S = 16.0 ± 2.3 (max 18.6; min 13.6); h = 14.1 ± 2.5 (max 16.5; min 11.6); d = 9.1 ± 1.4 (max 10.7; min 7.1).

Examined material: Holotype. DGM 3001 -I (10 specimens), 4223-I (2 specimens), 5001-I (3 specimens); MNRJ 3350 -I (1 specimen), 4341-I (1 specimen); MZSP 94822 (1 specimen), 98180 (1 specimen). Type material of Bulimulus sommeri : DGM 5411 -I (holotype).

Discussion: Among all the species previously classified as Itaborahia , only the type species, I. lamegoi , is here maintained in the genus. All the other species show different shell shapes and lack a concave outline, a prosocline aperture and a columellar fold. The other species previously classified in Itaborahia by Bergqvist et al. (2006) are here classified as Bulimulus trindadeae , Cyclodontina coelhoi and Cortana carvalhoi .

The holotype of Bulimulus sommeri Palma & Brito, 1974 ( DGM 5411-I; Figs. 50 ) is considered here as indistinguishable from Itaborahia lamegoi and, therefore, these species are synonyms. The paratype of B. sommeri ( MNRJ 5188-I) is a new species of the genus Eoborus Klappenbach & Olazarri, 1970 , and is described further in this work as E. fusiforme sp. nov.

Figures

FIGURES 43-50: 43-47. Itaborahia lamegoi (DGM 5001-I); shell length 30 mm. 43-45. Overview. 46. Imperforated umbilicus. 47. Smooth protoconch. 69-70. I. lamegoi (AMNH 24240; holotype); shell length 31.5 mm. 50. ”Bulimulus sommeri” (DGM 5411-I; holotype); shell length 20.5 mm.