Tag Archives: brazil

Defecation behaviour

A short research note was recently published by Carvalho & Oliveira. It is about the defecation behaviour of a terrestrial snail from Brazil, Cochlorina aurisleporis (Bruguière, 1792).

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After noting the overall scarcity of data in literature on this behaviour in many animals, the authors describe the process in this arboreal snail, which uses it muscles to form a more or less spherical pellet and finally drops the pellet onto the substrate beneath. They suggest as hypothesis to explain this behaviour that it may be a strategy to prevent detection by chemically oriented predators. Although this hypothesis is interesting, it would need further testing in the field. For a start, the predators of this species are unknown as the biology of Neotropical land snails is hardly documented in literature. The authors also made a statement its distribution, viz. “a purported (and unexpected) disjunct distribution”, being known from Madagascar and Brazil. It is simply based on an erroneous original locality in Bruguière (in the 18th and 19th century species were often described based on material collected by others and many times with vague, imprecise or even erroneous localities). Cochlorina aurileporis is purely a Brazilian species; it is unfortunate that the reviewers have overlooked this.

Reference:
Carvalho de Lima, T. & Oliveira, C.D. de Castro, 2020. Unusual shaping: The defacation bahavior in Cochlorina aurisleporis (Bruguière, 1792) (Gastropoda: Bulimulidae). – The Nautilus 134(1): 57-59.

Regional inventory Brazil

The continued inventory of Santa Catarina State in Brazil is subject of anothby eeAgudo-Padrón: “Based on the last list of non-marine molluscs from Santa Catarina State/SC published in March 2018, with 232 related forms, the current inventory of continental molluscs (land/terrestrial and limnic/freshwater) occurring in the State of Santa Catarina/SC is increased, with a new verified/confirmed registry of most other twenty (20) species (-fifteen (15) gastropods, thirteen (13) natives-Pomacea maculata Perry, 1810; Phyllocaulis sp (in determination process); Drepanotrema kermatoides (d’Orbigny, 1835); Anisancylus obliquus (Broderip & Sowerby, 1832); Drymaeus cf. paucipunctus (Pilsbry, 1898); Leiostracus cf. polygrammus (Moricand, 1836); Leiostracus sp (in determination process); Omalonyx matheroni (Potiez & Michaud, 1838); Peltella cf. palliolum (Férussac, 1821); Peltella iheringi Leme, 1968; Streptaxis cf. subregularis (Pfeiffer, 1846); Streptaxis cf. tumescens Suter, 1900; Gastrocopta cf. servilis (Gould, 1843); and two (2) non-native/exotic invasives forms – Ovachlamys fulgens (Gude, 1900); Galba (-Lymnaea) truncatula (Müller, 1774); …besides five (5) native bivalves-Diplodon charruana (d’Orbigny, 1835); Diplodon (-Rhipidodonta) suavidicus (Lea, 1856); Musculium argentinum (d’Orbigny, 1835); Eupera bahiensis (Spix, 1827); Cyanocyclas paranacensis (d’Orbigny, 1835) -), for a new total verified/ confirmed registry of 252 species and subspecies, sustained/consolidated product of complete 24 years of systematic field researches, examination of specimens deposited in collections of museums and parallel reference studies. Addition- al information regarding its known regional geographic distribution is incorporated/included“.

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Reference:
Agudo-Padrón, I., 2020. Additions to the Systematic Inventory of Non-Marine Molluscs Occurring in the State of Santa Catarina/SC, Central Southern Brazil Region. – Advances in Environmental Studies 4(1): 261-270. Link

New record for Brazil

Salvador et al. just published a new paper, of which the abstract is “We report the first Brazilian record of Leiostracus demerarensis (L. Pfeiffer, 1861) from Pará and Maranhão states. The distribution of this species now comprises Guyana, Suriname, French Guiana, and northern Brazil. Furthermore, given the uncertainty in generic and familial allocation of this species (either Bostryx Troschel, 1847, Bulimulidae, or Leiostracus Albers, 1850, Simpulopsidae), we used the barcoding segment of the COI gene to ascertain its classification in Simpulopsidae, retaining it as Leiostracus demerarensis. Moreover, Simpulopsis luteolus (Ancey, 1901) is also reported for the first time from Pará state“.

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The correct classification of this species was discussed a few years ago by Muratov & Gargominy in 2011, who considered it as a Bostryx species and based themselves on material collected in French Guiana. This new Brazilian record allowed the authors also check the molecular data, which confirmed its placement in Leiostracus. Hence a case where the DNA helped to judge between two conflicting views.

Reference:
Salvador, R.B. et al., 2020. First record of Leiostracus demerarensis (L. Pfeiffer, 1861) from Brazil (Gastropoda, Orthalicoidea), with a taxonomic reassessment. – CheckList 16(2): 507-512.

New Brazilian Rectobelus

A paper published last year describing a new species from Brazil is Simone & D’ávila. “Rectobelus levogyrus, a new species of subulinid, is described found in archaeological surveys in Amazon shell mounts (sambaquis) from Costa Marques, Rondônia, Brazil. It is the first sinistral subulinid species recorded in Brazil, and that is its main distinguishing character. A brief taxonomical treatment of the other congener species, R. rectus (Baker, 1927) (the type species, from Venezuela) and R. birabeni (Hylton Scott, 1946) (from Argentina) is included, with figures, as well as a discussion on the validity of the genus“.

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The title of this papers is curious, citing two different subfamily names, which are both outdated as the Subulininae are now considered as belonging to the Achatinidae. This is a very difficult group as the species are separated on minor details which are often not consistently studied in larger series. Many species from the ‘subulinid’ group are supposed to have continuous growth, making size differences difficult to use as a taxonomic characteristic. Moreover, for many species anatomical and molecular data are lacking. In this paper Simone disagrees with the opinion of Hausdorf, who considered Rectobelus H.B. Baker. 1927 as a synonym of Ischnocion Pilsbry, 1907. The latter is placed on MolluscaBase in the subfamily Coeliaxinae. Thus there remains ample room for further research.

Reference:
Simone, L.R.L. & D’ávila, 2019. The discovery of a sinistral Obeliscinae (Eupulmonata, Subulinidae) in Brazil, found in Amazon archaeological shell mounds of Rondônia. – Journal of Conchology 43(4): 327-336.

New streptaxid from Brazil

Salvador & Cunha just published a new paper, describing a new Brazilian species. “A new species of Streptartemon Kobelt, 1905 land snail from Santos, SE Brazil, is herein described as Streptartemon waukeen sp. nov., from specimens originally found in an urban garden. The new species is distributed along coastal urban areas from southern Espírito Santo state to São Paulo state. It can be diagnosed from its congeners by the following features: a comparatively small shell; the penultimate and body whorls bulging and rounded; a small and roughly circular aperture; and the lack of apertural lamellae/teeth. The new species also presents a bursa tract diverticulum, which is a plesiomorphic state in stylommatophoran snails, but absent in most streptaxid genera. Further details of the genital anatomy, as well as DNA barcoding information, are provided“.

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The discovery of this new taxon in urban areas is remarkable. Further collecting should show if this species is confined to anthropological habitats or not.

Reference:
Salvador, R.B. & Cunha, C.M., 2020. A new species of Streptartemon from southeastern Brazil (Gastropoda: Streptaxidae). – Journal of Conchology 43(5): 513-520.

Brazilian Obeliscus

Recently published by D’Avila e.a., a paper on Brazilian Obeliscus species. The abstract reads as follows: “Obeliscus agassizi Pilsbry, 1906 was described from specimens collected in Brazil, by J. G. Anthony, during the Agassiz expedition, in 1865. The type locality of the species was given simply as Brazil, without further information. More than a century after its description, this species was rediscovered during an expedition to the Biological Reserve of Pedra Talhada, Alagoas/Pernambuco states, Brazil. In the present study we provide detailed description of the anatomy of the soft parts of O. agassizi specimens, collected during this expedition, besides more precise data concerning the species occurrence. This work presents the first anatomical description for the genus. An annotated checklist of Obeliscus Beck, 1837 species is also provided. The species of Obeliscus have been traditionally distinguished by shell characteristics, mainly the general shell shape, number of whorls proportionally to the shell size, shell ornamentation, the shape of the protoconch and aperture size and shape. The distinction between species is often subtle. Considering that shell traits may be not sufficient as single taxonomic characters, other evidence for species boundaries, especially anatomical characters, is needed. Presently, it is not possible to discuss the taxonomic meaning of the set of anatomical characters described for O. agassizi, at the intra-genus level, as there is no information on the anatomy of the soft parts of other species of Obeliscus. The comparative analysis of the genital system of O. agassizi, Neobeliscus calcareus (Born, 1780), Stenogyra terebraster (Lamarck, 1822) and Rectobelus birabeni (Hylton-Scott, 1946) pointed out anatomical characters with potential diagnostic significance for the genus Obeliscus. However, the establishment of a definitive dif- ferential diagnosis for this genus, based in both conchological and anatomical traits, depends on the analysis of a greater number of species of Obeliscus, as well as species of other genera of Obeliscinae Thiele, 1931“.

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This is a useful paper, especially by providing anatomical details for this species and a checklist of other Brazilian species of the genus. However, the authors have missed the chance to add also molecular data to place this genus in the phylogentic data already available for the family. According to MolluscaBase the genus Obeliscus is classified in the Achatinidae (subfamily Stenogyrinae), no longer in the Subulinidae (subfamily Obeliscinae).

Reference:
D’ávila e.a., 2020. Resdiscovery of Obeliscus agassizi Pilsbry, 1906 (Gastropoda, Subulinidae, Obeliscinae), annotated checklist of species of Obeliscus beck, 1837 and first description of the anatomy for the genus. – Zoosystema 41(12): 159-172.

New records from Santa Catarina state

In the just issued Tentacle there is another contribution of Agudo & Meyer on new records in the Brazilian state of Santa Catarina.

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Agudo is tireless in bringing data on the malacofauna of this state to light, making it without doubt the most thoroughly researched part of Brazil.

Reference:
Agudo-Padron, I. & Meyer, D., 2020. Conservation of non-marine molluscs in Central Southern Brasil: new additions to the inventory of Santa Catarina state. – Tentacle, 28: 20-21.

Identity finally confirmed

Several years ago Ignacio Agudo published about a snail which he identified as Plekocheilus (Eurytus) from Santa Catarina state in Brazil. Based on a photograph of an immature specimen the species name aff. rhodocheilus Reeve, 1848 was added; a taxon of which only the type material exist from an unknown Brazilian locality.

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Now it appears that more specimens have been found and reared to adult stage. According to Agudo, the true identity of this species is completely different (but the external morphology is very similar): Mirinaba fusoides (Bequaert, 1948), family Strophocheilidae.

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Good to have this clarified and corrected. Note that this species appears to be eniantomorphic; both dextral and sinistral specimens have been found. This is a phenomenon quite rare, but seems to occur more often in Brazil as other examples (e.g., Corona) are known from that region.

Reference:
Agudo, I., 2020. Plekocheilus (Eurytus) aff. rhodocheilus (Reeve, 1848) (Gastropoda: Pulmonata: Amphibulimidae) from Santa Catarina State, SC, Central Southern Brazil region: a case of taxonomic identity resolved. – Bioma, 5 (54): 37-47. (Link)

Taxonomy of Polygyratia

Freshly pressed: a paper by Salvador & Cavallari on this genus. Their abstract is as follows: “Herein, we present a taxonomic revision of the genus Polygyratia Gray, 1847, with a new systematic placement in Scolodontidae and containing only the species Polygyratia polygyrata (Born, 1778). We offer an updated morphological description and geographical distribution, based on museum specimens and occurrence data gathered from literature and online database iNaturalist. We synonymise P. charybdis Mörch, 1852 with P. polygyrata. The species is known only from Atlantic Forest areas in Bahia state, eastern Brazil. We exclude three other species from the genus Polygyratia, classifying them as: Systrophia (Systrophia) heligmoida (d’Orbigny, 1835) and S. (Entodina) reyrei (Souverbie, 1858), based on conchological features; and S. (E.) pollodonta (d’Orbigny, 1835), though tentatively, based on scant published data. Finally, we present the first report of S. (S.) heligmoida (d’Orbigny, 1835) from Brazil“.

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It is good to have this revision of Polygyratia, with its new classification to the Scolodontidae. Personally I would like to see additional research, anatomical and molecular, on the 3 species which are now (tentatively) classified by these authors in Systrophia.

Reference:
Salvador, R.B. & Cavallari, D.C., 2020. Taxonomy and distribution of enigmatic ‘helicoid’ Polygyratia Gray, 1847 (Gastropoda, Stylommatophora). – Zoosystema and Evolution, 96(1): 91-101.

Snails from Fernando de Noronha

Recently published by Freitas et al., a survey at this archipelago. “Oceanic island biotas are known by their high levels of endemism and high vulnerability. In Brazil, only few islands have been studied. The present study reports general information on the distribution and abundance of terrestrial gastropods of the Fernando de Noronha archipelago, a group of islands 345 km off the Brazilian coast. In total, four species of land snails were recorded: the endemics Hyperaulax ridleyi (Smith, 1890) and Ridleya quinquelirata (Smith, 1890), and the widely distributed Beckianum beckianum (Pfeiffer, 1846), and Allopeas gracile (Hutton, 1834). The most abundant species was H. ridleyi. By reporting the present situation of native land snails of Fernando de Noronha, this study provides data that could help in their conservation, comprising an important first step for planning future conservation strategies for the land biota of the whole archipelago“.

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Reference:

Freitas, A.V.L. et al., 2019. Land snails of the Fernando de Noronha archipelago, Brazil. – American Malacological Bulletin, 37(2): 66-69.