Tag Archives: literature

Achatina fulica east of Andes in Ecuador

Goldyn et al. have just published a paper of which the abstract reads “[w]e are reporting the first locality of invasive giant African snail, Achatina (Lissachatina) fulica (Férussac, 1821) in the Ecuadorian Amazon. It was found present in 32 out of 50 urban sites studied. The abundance where present was relatively high when compared to literature from other parts of the world. The snails were found in aggregations, usually foraging — most often on dogs’ feces. Statistical analysis suggests a preference toward this source of alimentation. This is the first report of such preference in this species, which is highly significant considering the possible implications. Besides the threat posed by an invasive species to the invaluable ecosystems of the Amazon, the pathogens transferred by A. fulica combined with a high abundance of the species in an urban environment and its food preferences may constitute an important health hazard for local human populations”.

This is, however, not the first published occurrence east of the Andes in Ecuador. The same authors have published this, and additional data, before in Folia Malacologica last year. If not an oversight by the reviewers and editor, this so-called “first locality” has to be blamed to the authors.

But the fact as such (if we exclude the many Brazilian occurrences), unfortunately, was waiting just to happen. Hopefully the Ecuadorian authorities nowadays know how they should eradicate this pest before it becomes wide-spread in this area which contain many endemic species.

Reference:
Goldyn, B., et al., 2017. Urban ecology of invasive giant African snail Achatina fulica (Férussac) (Gastropoda: Achatinidae) on its first recorded sites in the Ecuadorian Amazon. – American Malacological Bulletin, 35: 59-64.

New Epiphragmophoridae from Brazil

Just published: a paper by Cuezzo & Pena describing a new genus and species of Epiphragmophoridae; their abstract reads as follows “We describe a new genus and a new species in the family Epiphragmophoridae, Minaselates paradoxa sp. n. The new species was found at the National Park Cavernas do Peruaçu, in northern portion of the state of Minas Gerais, Brazil. Minaselates paradoxa sp. n. is classified in Epiphragmophoridae based on the fact that it shares the following diagnostic features of the family: a dart apparatus with a single dart sac, and two unequal mucous glands at the terminal genitalia. Minaselates gen. n. differs from Epiphragmophora Doering, 1874 by having a granulose protoconch, shell spire with blunt apex, complex microsculpture on the teleoconch and closed umbilicus fused with the shell wall. Also, significant differences between the two genera are the presence of a long and thin kidney that extends more than half the length of the pulmonary cavity, the presence of a flagellar caecum, and a smooth jaw in Minaselates gen. n. The finding of this new species and genus is particularly significant to refine the definition of the family, since Epiphragmophoridae has been traditionally diagnosed using the same characters of Epiphragmophora. Dinotropis Pilsbry & Cockerell, 1937, the other valid genus in the family, is monospecific and is only known by the morphology of the shell. In many ways it is similar to Epiphragmophora. A cladistics analysis was made in the present study which supports Minaselates gen. n. as a different entity and as sister group of the Epiphragmophora within Epiphragmophoridae”.

Reference:
Cuezzo, M.G. & Pena, M.S., 2017. Minaselates, a new genus and new species of Epiphragmophoridae from Brazil (Gastropoda: Stylommatophora: Helicoidea). – Zoologia, 34: e13240 (12 pp.). DOI: 10.3897/zoologia.34.e13230

Fossil connections

Recently a review paper appeared by Hammouda et al. (2017), in which some links between northern Africa and South America are suggested. The abstract is as follows:

“Terrestrial gastropods occur in many North African localities in Eocene continental deposits. Here we analyse the faunal assemblage from the Hamada de Méridja Formation in southwestern Algeria, dated as Early to Middle Eocene on the basis of charophytes. The assem- blage consists of three closely related species that to date have been classified either in the extant Madagascan genus Leucotaenius v. Martens, 1860, or in the SW European Eocene genera Romanella Jodot, 1957 and Vicentinia Jodot, 1957. This is rejected for shell morphological and phylogeographical reasons, and a new classification as Maghrebiola gen. nov. is proposed. Maghrebiola is tentatively placed in the South American family Strophocheilidae, as species from the Early Eocene Itaboraí Basin of Brazil, currently placed in the genus Eoborus Klappenbach and Olazarri, 1970 in the family Strophocheilidae, superfamily Acavoidea, have a very similar shell habitus. This record possibly extends the known geographical range of the Strophocheilidae into the African continent during the Eocene. Immigration of this stock into North Africa during the Cretaceous via a still existing plate connection is assumed. An attribution of Maghrebiola to the African family Achatinidae is unlikely for shell morphological reasons despite certain habitus similarities, although the Priabonian genera Arabicolaria and Pacaudiella from Oman most likely belong into this family, and not to the Vidaliellidae as originally proposed. Possible causes for the very low diversity of the assemblage are mainly unfavourable living conditions, i.e. a relatively dry climate resulting in sparse vegetation and only occasional presence of water bodies, which may have had increased salinities, accounting for the lack of freshwater mollusks. The absence of any competing large gastropods may possibly have facilitated high intraspecific variability leading to sympatric occurrence of three closely related species, due to the animals occupying a wide range of available ecological niches. As the species discussed here have also been attributed to the genera Romanella and Vicentinia in the Vidaliellidae, we provide an appendix with annotated characterisations of most genera of the Vidaliellidae and list the nominal species assigned to them. This family is tentatively placed in the South American superfamily Orthalicoidea; its stock would have similarly immigrated from South America, but have successfully colonized mainly SW Europe, with only one Eocene species [Romanella kantarensis (Jodot, 1936)] recognized in Algeria”.

This paper presents a provoking view on the relations between northern Africa, soutwestern Europe and South America during the Eocene. Perhaps food for discussion among palaeontologists?

Reference:
Hammouda, S.A., Kadolsky, D., Adaci, M., Mebrouk, F., Bensalah, M., Mahboubi, M. & Tabuce, R., 2017. Taxonomic review of the ‘‘Bulimes’’, terrestrial gastropods from the continental Eocene of the Hamada de Méridja (northwestern Sahara, Algeria) (Mollusca: Stylommatophora: Strophocheilidae?), with a discussion of the genera of the family Vidaliellidae. – Paläontologische Zeitschrift, 91: 85-112.

Reproductive biology of a Megalobulimus species

Fontenelle & Miranda have just published a paper on Megalobulimus. Their abstract reads “We studied the reproductive biology of Megalobulimus paranaguensis (Pilsbry & Ihering, 1900), a large and long-lived land gastropod from the Atlantic Rainforest of Brazil. The study was conducted at an urban park in the city of Santos, state of São Paulo. For 4 years, we counted the egg postures and annual eclosion rate of 32 captive snails and looked for associations between egg posture and the climatical variables of the period. The annual mean posture of 8.7 eggs per snail obtained in our results is a small number, but typical of Brazilian macromollusks. The annual eclosion rate was 31%. The beginning of the annual activity period of snails occurred in the middle of March, and lasted 33.97±3.02 weeks. The dormancy period started in the beginning of November, and lasted 18.39±3.11 weeks. There were two egg posture peaks, a minor peak between March and May, and a major peak between August and November, with greater values in September. Megalobulimus paranaguensis has a well-defined seasonal reproductive pattern influenced by environmental temperature and temperature range. Furthermore, in this snail, reproduction is negatively influenced by temperature increasing and temperature range”.

Schermafbeelding 2017-04-06 om 20.55.36

Reference:
Fontenelle, J.H. & Miranda, M.S., 2017. Aspects of biology of Megalobulimus paranaguensis (Gastropoda, Acavoidea) in the coastal plain of the Brazilian southeast. – Iheringia, Zoologia, 107: e2017004 (5 pp.). DOI: 10.1590/1678-4766e2017004

An Omalonyx revisited

Arruda et al. (2016) recently published a revaluation of an Omalonyx species from Brazil. Species from this group are notoriously difficult to discern. “Omalonyx geayi Tillier, 1980 was originally described on the basis of specimens from Kaw swamp, French Guiana. This species distinguished from other of Omalonyx d’Orbigny, 1837: (i) by hermaphrodite duct twice as long and sacculate, without radial ducts but a funnel-shaped insertion on the ovariotestis, and (ii) by longitudinal wrinkled folds on the phallus inner wall. Two recent collections – from Trinidad and Carauari (Amazonas, Brazil) included specimens with ovariotestis and hermaphrodite duct morphologies similar to that originally described for O. geayi, but with phallus morphology not consistent with identification as O. geayi. A further eight lots, from Suriname, Ecuador, Brazil (Amazonas and Alagoas States), Bolivia and Cayenne-Kourou Road in French Guiana comprised specimens with phallus morphology analogous to O. geayi and ovariotestis and hermaphrodite duct similar to that of other Omalonyx species. Based on histological examination, and earlier phylogenetic analyses of morphological characters, we conclude that the ovariotestis and hermaphrodite duct conditions previously described for O. geayi were based on parasitized specimens. Accordingly, O. geayi is redescribed, and new information presented on the species’ wide distribution in South America”.

Schermafbeelding 2017-04-05 om 10.02.04

Based on histological and anatomical research, the authors conclude that the original description was based on parasitised specimens in which the ovariotestis and proximal hermaphrodite duct were deformed. O. geayi as currently understood is occurring more broadly in South America than previously thought. The study was based on specimens from Trinidad, Suriname, French Guiana, Ecuador, and Brazil.

Reference:
Arruda, J.O., Barker, G.M. & Thomé, J.W., 2016. Revaluation of the taxonomic characters and distribution of Omalonyx gaeyi (Gastropoda, Succineidae). – Iheringia, Zoologia, 106: e2016019 (6 pp.). DOI: 10.1590/1678-4766e2016019

New fossil Pupoides

Cabrera & Martinez (2017) have just published a paper on minute pupillids. “A new species of Pupoides Pfeiffer 1854, subgenus Ischnopupoides Pilsbry 1926, is described for the Late Cretaceous of Uruguay (Queguay Formation), being the oldest record of the genus and subgenus. Pupoides (I.) gnocco new species is characterized by a small dextral fusiform shell, constituted by a spire comprising five slightly convex whorls, oblicuous axial ornamentation, subrounded aperture, and an expanded outer lip that lacks dentition”.

Reference:
Cabrera, F. & Martinez, S., 2017. Late Cretaceous Pupoides Pfeiffer 1854 (Gastropoda: Pupillidae) from  Uruguay (Queguay Formation). – Journal of Conchology, 42 (5):333-338.