RESUMO
Juliana Alvim and Alexandre Dias Pimenta (2016) The taxonomy of Pleurobranchus from Brazil is little known because the internal anatomy and possible intraspecific variation are poorly understood. This study recognizes three valid species from Brazil: Pleurobranchus areolatus Mörch, 1863, P. iouspi Ev. Marcus, 1984 and P. reticulatus Rang, 1832. Pleurobranchus reticulatus and P. areolatus were misidentified for a long time because of their simple descriptions, without photographs of living animals. However, they are distinguished by: color of the rhinophores, P. reticulatus has a uniform color, while P. areolatus has the same pattern as the dorsum; P. reticulatus is larger and has more pinnae free from the body wall than P. areolatus; the prostate is tubular and highly convoluted in P. reticulatus, while in P. areolatus is elongated with the proximal portion rounded; and, the jaws of P. areolatus, the smaller species, have more rows and fewer platelets per row than P. reticulatus. Pleurobranchus emys and P. iouspi are considered synonyms based on the examination of portions of the types, mainly due the presence of a dense layer of spicules in the mantle and because their original descriptions do not differ significantly. A discussion about some possible synonymies was provided and their recognition were based mainly on the diameter of the tubercles of the mantle, the presence/absence of flaps that surrounds the gonopore and the development of a leaflet in the convex portion of the penis. The detailed anatomical study allowed recognition of a general pattern in the position and presence or absence of extrinsic and intrinsic odontophore muscles for Pleurobranchus. The circulatory and nervous systems do not provide useful characters for species delimitation.
RESUMO
Four new species of the pyramidellid Odostomiinae from Brazil are described: Chrysallida conifera sp. nov., characterized by a small and regularly conical shell with prominent nodules; Parthenina biumbilicata sp. nov., characterized by a deep and wide umbilicus and a regularly increasing aperture diameter at the protoconch, which bears a small circular umbilicus; Eulimastoma franklini sp. nov., which is very similar to Eulimastoma dydima (Verrill & Bush, 1900) but has a prominent helicoid protoconch; Eulimastoma exiguum sp. nov., similar to Eulimastoma weberi (Morrison, 1965) but without spiral ridges. Fargoa diantophila (Wells & Wells, 1961) and Chrysallida nioba (Dall & Bartsch, 1911) are reported from the southwestern Atlantic for the first time.
RESUMO
Four new species of the pyramidellid Odostomiinae from Brazil are described: Chrysallida conifera sp. nov., characterized by a small and regularly conical shell with prominent nodules; Parthenina biumbilicata sp. nov., characterized by a deep and wide umbilicus and a regularly increasing aperture diameter at the protoconch, which bears a small circular umbilicus; Eulimastoma franklini sp. nov., which is very similar to Eulimastoma dydima (Verrill & Bush, 1900) but has a prominent helicoid protoconch; Eulimastoma exiguum sp. nov., similar to Eulimastoma weberi (Morrison, 1965) but without spiral ridges. Fargoa diantophila (Wells & Wells, 1961) and Chrysallida nioba (Dall & Bartsch, 1911) are reported from the southwestern Atlantic for the first time.
RESUMO
Four new species of the pyramidellid Odostomiinae from Brazil are described: Chrysallida conifera sp. nov., characterized by a small and regularly conical shell with prominent nodules; Parthenina biumbilicata sp. nov., characterized by a deep and wide umbilicus and a regularly increasing aperture diameter at the protoconch, which bears a small circular umbilicus; Eulimastoma franklini sp. nov., which is very similar to Eulimastoma dydima (Verrill & Bush, 1900) but has a prominent helicoid protoconch; Eulimastoma exiguum sp. nov., similar to Eulimastoma weberi (Morrison, 1965) but without spiral ridges. Fargoa diantophila (Wells & Wells, 1961) and Chrysallida nioba (Dall & Bartsch, 1911) are reported from the southwestern Atlantic for the first time.
RESUMO
The taxonomy of the species of Metaxia Monterosato, 1884 from Brazil is revised. Previously to this study, only Metaxia excelsa Faber & Moolenbeek, 1991 was known to occur in this country, under its older name Metaxia exilis (C.B. Adams, 1850). The review of a large amount of shells in malacological collections in Brazil revealed the occurrence of three known additional species: Metaxia taeniolata (Dall, 1889); Metaxia rugulosa (C.B. Adams, 1850); Metaxia prompta Rolán & Fernández-Garcés, 2008, all previously reported from the southeast coast of the USA and/or the Caribbean region. Metaxia gongyloskymnus sp. nov., diagnosed by the globose protoconch with continuous axial ribs and microscopic spiral sculpture, is restricted to localities off the Southeastern Brazilian coast.
RESUMO
The taxonomy of the species of Metaxia Monterosato, 1884 from Brazil is revised. Previously to this study, only Metaxia excelsa Faber & Moolenbeek, 1991 was known to occur in this country, under its older name Metaxia exilis (C.B. Adams, 1850). The review of a large amount of shells in malacological collections in Brazil revealed the occurrence of three known additional species: Metaxia taeniolata (Dall, 1889); Metaxia rugulosa (C.B. Adams, 1850); Metaxia prompta Rolán & Fernández-Garcés, 2008, all previously reported from the southeast coast of the USA and/or the Caribbean region. Metaxia gongyloskymnus sp. nov., diagnosed by the globose protoconch with continuous axial ribs and microscopic spiral sculpture, is restricted to localities off the Southeastern Brazilian coast.
RESUMO
The taxonomy of the species of Metaxia Monterosato, 1884 from Brazil is revised. Previously to this study, only Metaxia excelsa Faber & Moolenbeek, 1991 was known to occur in this country, under its older name Metaxia exilis (C.B. Adams, 1850). The review of a large amount of shells in malacological collections in Brazil revealed the occurrence of three known additional species: Metaxia taeniolata (Dall, 1889); Metaxia rugulosa (C.B. Adams, 1850); Metaxia prompta Rolán & Fernández-Garcés, 2008, all previously reported from the southeast coast of the USA and/or the Caribbean region. Metaxia gongyloskymnus sp. nov., diagnosed by the globose protoconch with continuous axial ribs and microscopic spiral sculpture, is restricted to localities off the Southeastern Brazilian coast.