Eoborus fusiforme, Salvador & Simone, 2013

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

Eoborus fusiforme sp. nov.

( Figs. 84-87 )

Holotype: MNRJ 5188 -I ( Figs. 84-87 ).

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 Sequences S1 and S2, the same sequences of occurrence of Eoborus sanctijosephi ( Medeiros & Bergqvist, 1999; Bergqvist et al. 2006).

Age : Tertiary, Middle Paleocene.

Etymology: The Latin word fusiforme (meaning “spindleshaped”) refers to the species conspicuous shell shape.

Diagnosis: Shell small for genus, fusiform. Acuminat- ed spire. Whorls flat. Aperture elliptical, with upper palatal region of outer lip meeting continuously with preceding whorl, accompanying the whorl outline.

Description: Shell medium-sized, fusiform; small for family, less than 2 cm. Spire angle ~55°. Greatest width on body whorl; width ~½ shell length. Spire acuminated. Protoconch smooth, conspicuous; transition to teleoconch clear. Teleoconch with fine, well-marked and oblique growth lines. Profile of whorls flat. Suture well-marked. Aperture elliptical, prosocline, with upper palatal region of outer lip meeting continuously with preceding whorl, accompanying whorl outline; without lamellae or teeth; aperture ~2/5 shell length and ~⅔ shell width. Peristome ample, smooth, greatly reflected. Body whorl ~⅔ shell length. Umbilicus wide.

Measures (in mm): Holotype: 6 whorls; H = 18.3; D = 9.3; S = 9.6; h = 8.3; d = 6.0; H/D = 1.96; h/d = 1.37.

Examined material: Holotype.

Discussion: The only known specimen of E. fusiforme has been previously misidentified as the paratype ( MNRJ 5188-I) of Bulimulus sommeri Palma & Brito, 1974 . However, it clearly belongs to a different species; especially when considering that B. sommeri is a junior synonym of Itaborahia lamegoi . E. fusiforme differs from E. sanctijosephi and E. rotundus by its much smaller size, fusiform shell, acuminated spire, flattened whorls and prosocline aperture. Moreover, it differs from E. rotundus by the way in which the upper palatal region of outer lip meets with the preceding whorl, which is continuous and accompanies the whorl outline; this character E. fusiforme shares with E. sanctijosephi .

Family Urocoptidae

Genus Brachypodella Beck, 1837 “ Brachypodella” britoi Ferreira & Coelho, 1971

( Figs. 88-90 )

Brachypodella britoi Ferreira & Coelho, 1971: 470 (figs. 8-9); Palma & Brito, 1974: 397 (pl. 1, fig. 8); Simone & Mezzalira, 1994: 51 (pl. 15, fig. 426); Bergqvist et al., 2006: 60 (fig. 78).

Holotype: MNRJ 5024 -I (destroyed, examined).

Paratype: MNRJ 5025 -I (1 specimen, examined; Fig. 88 ) , MNRJ 5026 -I (5 specimens, examined; Figs. 89-90 ) .

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: Sequence S1 ( Medeiros & Bergqvist, 1999; Bergqvist et al., 2006).

Age : Tertiary, Middle Paleocene.

Etymology: Species dedicated to Prof. Ignácio M. Brito (Instituto de Geociências da Universidade Federal do Rio de Janeiro, UFRJ, Rio de Janeiro, Brazil).

Diagnosis: Protoconch smooth. Teleoconch sculptured by strong and well-marked ribs. Body whorl slightly detached from previous whorl. Peristome reflected.

Re-Description: Shell conical-turriform, multispiral, high. Spire angle ~20°. Protoconch smooth. Teleoconch sculptured by strong, well-marked, regularly space ribs; on last whorls, the ribs from a whorl are coincident with the ones on previous whorl. Suture well-marked, oblique (diagonal) to columellar axis. Profile of whorls slightly convex. Aperture rounded, slightly oblique, forming angles in transition from palatal and columellar regions to parietal region, being straight. Body whorl slightly detached from previous whorl. Peristome lightly reflected.

Examined material: Types.

Discussion: Brachypodella is a recent genus that occurs in southern North America, Central America, Caribbean Islands and northern South America, approximately the same distribution of the family ( Schileyko, 1999a). The typical character of the genus is the presence of a keel on the basal portion of the body whorl ( Schileyko, 1999a).

Little information can be obtained about Brachypodella britoi since there is not a single well-preserved specimen; they consist only of fragments. Moreover, the holotype was completely destroyed. Still, there is some information to be extracted from these fragments, as for example, the supposed conical-turriform shell shape, similar to other species in the genus and commonplace in the family ( Schileyko, 1999a).

Important characters in the familiar allocation of B. britoi are: the conical-turriform shell shape, sculpture pattern and the body whorl detached from previous whorl, very common in Urocoptidae ( Schileyko, 1999a). The original illustration of Ferreira & Coelho (1971: p. 471, fig. 8) shows the body whorl greatly detached from the previous one. However, this degree of detachment is not seen in the specimens - the body whorl is only slightly detached ( Fig. 88 ). Brachypodella britoi , as Brasilennea arethusae , has few ribs per whorl, but they are raised and strong. Quensen & Woodruff (1997) relates these ribs to a greater protection against shell-breaking predators in Cerion Röding, 1798 . Unfortunately, there is no known malacophagous predator in Itaboraí in Sequence S1.

The holotype was the only specimen with a protoconch (as indicated by the original illustration in Ferreira & Coelho, 1971). Ferreira & Coelho (1971) also stated that the first whorl of the protoconch is very prominent but this feature could not be checked, since the holotype is destroyed. The protoconch is an important character for classification; Ferreira & Coelho (1971) decided to allocate the species in the genus Brachypodella precisely because the prominent protoconch of B. britoi was similar to the protoconch of B. erratica Pilsbry, 1930 . However, loss of the protoconch is a well-disseminated character in Urocoptidae , including the genus Brachypodella ( Schileyko, 1999a).

The aperture can be seen in a single specimen (a paratype) and it is hard to tell if it is complete or not. In any case, the aperture seems to be rounded, slightly oblique, without lamella or teeth and with a slightly reflected peristome. Moreover there is no keel on the basal portion of the body whorl; its presence is also a typical feature of the genus ( Schileyko, 1999a).

Therefore, B. britoi has a protoconch and lacks the keel on the body whorl, going against the common features of the genus ( Schileyko, 1999a). This suggests that this species could be transferred to a more suitable genus or even that a new genus could be erected to receive it. Moreover, the distant temporal and spatial occurrences could also warrant the creation of a new genus. Nevertheless, here we choose a more conservative approach, simply leaving the genus in doubt as “ Brachypodella” britoi , until more specimens are found.

Family Gastrocoptidae

Genus Gastrocopta Wollatson, 1878 Gastrocopta mezzalirai ( Ferreira & Coelho, 1971) comb. nov.

( Figs. 91-93 )

Vertigo mezzalirai Ferreira & Coelho, 1971: 468 (fig. 5); Palma & Brito, 1974: 397; Simone & Mezzalira, 1994: 49 (pl. 14, fig. 412); Bergqvist et al., 2006: 60 (fig. 79).

Holotype: MNRJ 5018 -I-A (examined; Figs. 91-93 ).

Paratype: MNRJ 5019 -I (11 specimens, examined) .

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: Sequence S1 ( Medeiros & Bergqvist, 1999; Bergqvist et al., 2006).

Age : Tertiary, Middle Paleocene.

Etymology: Species dedicated to Sergio Mezzalira (Instituto Geográfico e Geológico, São Paulo, Brazil).

Diagnosis: Shell smooth, oval with flattened base. Greatest width on body whorl. Aperture sub-rectangular, with two teeth: one large parietal and one small columellar.

Re-Description: Shell diminutive, oval with flattened base. Greatest width on body whorl; width ~¾ shell length. Spire angle ~60°. Spire apex not protuberant. Protoconch flattened, blunt, smooth; transition to teleoconch not clear. Shell smooth, except for growth lines. Profile of whorls convex. Suture weakly marked, slightly oblique (diagonal) to columellar axis. Aperture medium-sized, orthocline, sub-rectangular; aperture ~⅓ shell length and ~½ width. Peristome reflect- ed, incomplete (absent in parietal region). Aperture with two teeth, one large and strong parietal and one small columellar; none extending itself towards interior. Parietal tooth ~½ aperture height. Body whorl ~⅓ shell length.

Measures (in mm): Holotype: 5 whorls; H = 1.7; D = 1.3; S = 1.1; h = 0.5; d = 0.4; H/D = 1.31; h/d = 1.25.

Examined material: Types. MNRJ 5042 -I (44 specimens) .

Discussion: Vertigo O.F. Müller, 1773 is a diverse genus with a Holartic distribution ( Schileyko, 1998b). Gastrocopta Wollatson, 1878 is a typical American genus, occurring on the whole continent ( Schileyko, 1998b) and being the only gastrocoptid genus in Brazil ( Simone, 2006). This was the main criterion used to transfer V. mezzalirai to Gastrocopta , since morphological diagnosis in the family is difficult ( Schileyko, 1998b). Still, some morphological characters, like the aperture dentition, are useful and were also taken into account.

The diminutive size is common in Gastrocoptidae , but G. mezzalirai is a little smaller than the mean, not even reaching 2 mm. Its shell shape is also slightly different from the norm in the genus: it is not as cylindrical and has its greatest width on the body whorl. However, there are species in this genus with similar shape like, for instance, G. contracta (Say, 1822) . The aperture of G. mezzalirai is very much like the norm in the genus, yet it shows a characteristic of its own: the reflected lip gives the aperture an approximately rectangular shape. Again, regarding both the shape and position of the aperture, G. mezzalirai is very similar to G. contracta . In their original description of G. mezzalirai, Ferreira & Coelho (1971) stated the affinity of G. mezzalirai to Vertigo ovata Say, 1882 ; however, V. ovata ’s shell is typical of the genus and here we could not find any similarity between these two species besides those expected for two members of the same family.

G. mezzalirai has some of the typical dentition in the family: a large parietal tooth and a small columellar tooth. Dentition is greatly variable in the family; gastrocoptids may have from none to six teeth. The strong parietal tooth (actually a fusion of the parietal and angular lamellae) occluding half the aperture seen in G. mezzalirai is typical of the genus Gastrocopta ( Schileyko, 1998b) . These teeth do not extend themselves towards the shell interior, indicating that their function should have been protection against predators that attack trough the aperture ( Solem, 1972; Goodfriend, 1986; Stanley, 1988; Vermeij, 1993; Gittenberger, 1996; Barker & Efford, 2004).

Figures

FIGURES 78-85: 78-79. Eoborus sanctijosephi (DGM 4992). 78. Smooth protoconch.79. Umbilicus. 80. E. sanctijosephi (AMNH 24241; holotype); shell length 44 mm. 81-83. E. sanctijosephi; specimen previously classified as Vorticifex fluminensis (DGM 5003-I; holotype); greater width 8.5 mm. 84-85. Eoborus fusiforme sp. nov. (MNRJ 5188-I; holotype); shell length 18.5 mm.

FIGURES 86-97: 86-87. Eoborus fusiforme sp. nov. (MNRJ 5188-I; holotype); shell length 18.5 mm. 88. ”Brachypodella” britoi (MNRJ 5025-I; paratype); shell length 4 mm. 89-90. “Brachypodella” britoi (MNRJ 5026-I; paratype); shell length (both) 4 mm.91-93. Gastrocopta mezzalirai (MN 5018-I-A; holotype); shell length 1.5 mm. 94-96. Gastrocopta itaboraiensis sp. nov. (MNRJ 5018-I-B; holotype); shell length 1.5 mm. 97. Biomphalaria itaboraiensis (DGM unnumbered); greater width 5 mm.