Brasilennea guttula, R. B. Salvador & Simone, 2012

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

Brasilennea guttula Salvador & Simone, 2012

( Figs. 17-21 )

Brasilennea guttula Salvador & Simone, 2012: 2 (figs. 1-4).

Holotype: MCT 6940 -I (examined; Figs. 17-21 ).

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. The precise stratigraphic occurrence can’t be assessed; probably Sequence S1, the same sequence of occurrence of the other Brasilennea species ( Medeiros & Bergqvist, 1999; Bergqvist et al. 2006).

Age : Tertiary, Middle Paleocene.

Etymology: The name refers to the species’ intriguing shell shaped as a water drop.

Diagnosis: Outline shaped like water drop (spire sharply acuminate) instead of pupiform. Greatest width on body whorl. Larger number of whorls (about 14).

Description: See Salvador & Simone (2012).

Measures (in mm): Holotype: 14 whorls; H = 13.6 (aperture broken); D = 6.5; S = 11.3.

Examined material: Holotype. Discussion: B. guttula is smaller than B. arethusae but larger than B. minor , and has more whorls than both ( B. guttula has 14, while B. arethusae has 10-11 and B. minor has 8-9). The most striking difference, however, is its “water drop” shape, i.e., an acuminate spire (the other species have wide, dome-shaped first whorls). Regarding the other typical features of the genus, B. guttula shares all of them: the shell strength, the smooth protoconch, the sculpture pattern, the suture pattern and the most prominent feature of the genus, the two furrows on the body whorl. Nevertheless, the holotype (the only specimen known) has the last portion of the body whorl broken, so for now there is no clue indicating if the peristome has a doubled aspect or if there was a parietal lamella and/or a columellar lamella as in the other two Brasilennea species.

Figures

FIGURES 10-19: 10-11. Brasilennea arethusae (AMNH 24237; holotype); shell length 23.5 mm. 12. B. arethusae (AMNH 24238; paratype); shell length 24 mm. 13. Anomalous specimen of B. arethusae (DGM 4998-I); shell length 27 mm. 14-15. ”Strobilopsis mauryae” (MNRJ 5020-I; holotype); greater width 4.5 mm. 16. B. arethusae (AMNH 24239; paratype); greater width 7.5 mm. 17-19. Brasilennea guttula (MCT 6940-I; holotype); shell length 13.5 mm.

FIGURES 20-31: 20-21. Brasilennea guttula (MCT 6940-I; holotype), showing the two spiral furrows on the body whorl; shell length 13.5 mm. 22. Brasilennea minor (DGM 4221-I; holotype); shell length 9 mm. 23-24. B. minor (DGM 4999-I); shell length 11.5 mm. 25. Taller specimen of B. minor (DGM 4999-I); altura 15 mm. 26. B. minor (DGM 4999-I) with broken aperture, showing the parietal (pt) and columellar (cl) lamellae. 27. Temesa magalhaesi (DGM 4220-I; holotype); shell length 14.5 mm. 28-31. T. magalhaesi (DGM 4997-I); shell length 14 mm.