A new synonym from Brazil

Silva et al. just published a research note on a Brazilian land snail. There is no abstract, but their first sentence gives a nice summary of the paper: “Helicodiscus Morse, 1864 (family Helicodiscidae) is a genus of terrestrial snails with over 20 valid species (MolluscaBase 2020) and distributed almost exclusively over North America (Solem 1984). Helicodiscus theresa Thiele, 1927 has been described as native to Brazil, but herein we reassert the identity of this species as the North American Helicodiscus parallelus (Say, 1821), exotic to Brazil”.

Reference:
Silva, F.S., Forsyth, R.G. & Salvador, R.B., 2020. Helicodiscus theresa from Brazil is the exotic species Helicodiscus parallelus (Gastropoda, Helicodiscidae). – Strombus 26(1-2): 15-18.

St. Martin molluscs

Published today: a new paper by Hovestadt and Neckheim contributing to the knowledge of the Caribbean fauna. Their abstract is as follows: “The non-marine malacofauna of St. Martin is critically revised. Forty-seven terrestrial taxa and 7 freshwater taxa are accepted as being part of the non-marine malacofauna. The fauna is compared with the fauna of the much less known islands of Saint-Barthélemy and Anguilla. Pleurodonte guadeloupensis martinensis is described as a new subspecies, endemic for St. Martin”.

Their abstract is very concise, but the paper contains a wealth of data on the land and freshwater snails of these three islands mentioned. They also describe a new subspecies (illustrated above in figs 3-6) and in two appendices locality data an overview is given of the fauna of a fourth island, Tintamarre.

Reference:
Hovestadt, A. & Neckheim, C.M., 2020. A critical checklist of the non-marine molluscs of St. Martin, with notes on the terrestrial malacofauna of Anguilla and Saint-Barthélemy, and the description of a new subspecies. – Folia Conchyliologica 57: 1-38.

New Brazilian cave species

Just published: a paper by Simone et al. of which the abstract reads as follows: “The genus Habeastrum Simone, 2019 was recently described based on empty shells, counting with two troglobite species. Concho- logical features allowed a preliminary classification in the caenogastropod family Diplommatinidae, but this family allocation was left open to future studies. Herein, we present a detailed anatomical study of newly acquired specimens, confirming the classification in Diplommatinidae. These new specimens, from Minas Gerais state, SE Brazil, belong to a new troglobite species described herein, Habeastrum strangei sp. nov. The present records extend the genus distribution ca. 1,100 km east-northeast.”.

This is an interesting paper on a fauna clearly hardly researched, and so we might expect more interesting papers on this topic in the future. The anatomical data are also interesting as they add to insights in a group for which these data were still lacking.

Reference:
Simone, L.R.L. et al., 2020. A new troglobite species of Habeastrum Simone, 2019 from Brazil, and support for classification in Diplommatinidae (Mollusca, Caenogastropoda). – Zoosystematics and Evolution 96(2): 639-647.

New Orthalicoid fossils

A recent paper adds new data to a family of fossils that are supposed to be part of the superfamily Orthalicoidea and thus have links to the Neotropics. The abstract reads as follows: “The vidaliellids were a family of gastropods with an abundant fossil record in Palaeogene rocks from southwestern Europe and north Africa. However, their palaeobiogeographic patterns of dispersal and their phylogeny are still not fully understood. In this paper, we revisit two gastropod species from the Palaeogene of Mallorca (Balearic Islands, western Mediterranean), which can be classified within the family Vidaliellidaes. Selvovum nov. gen. is described to contain the species “Ampullaria” selvensis, a large and ovoid vidaliellid that lived in the swamps and forests of the late Eocene of Mallorca. Calculocochlea oliveri nov. gen. nov. sp. is described for another, medium-sized land snail that thrived among the riverine forests and bush- lands of the early Oligocene of Mallorca. Relationships of this latter taxon with the Vidaliellidae remain contentious because of its particular ornamentation and its lack of a reflected peristome. These two new taxa suggest high habitat diversity for the Vidaliellidae, and they show that Mallorca was a refugium for vidaliellids, which became extinct in the Iberian Peninsula and southern France towards the end of the middle Eocene”

Stronger than with extant species, the relationships of fossils is often based on hypotheses. In this case, this family is sopposed to have originated from “a migration event from South America via west Africa that would have occurred during the Early Creta- ceous, prior to the loss of land connection due to the open- ing of the South Atlantic Ocean. This scenario hinges on the classification of the Vidaliellidae within Orthalicoidea and on the classification of Maghrebiola in Rhytidoidea: Strophocheilidae”. We will see if this hypothesis will be sustainable in the future.

Reference:
Juarez-Ruiz, J. et al., 2020. Shape and habitat disparity in Palaeogene land snails (Stylommatophora, Orthalicoidea, Vidaliellidae) of southwestern Europe: two new bulimoid genera from the Palaeogene of Mallorca (Balearic Islands, western Mediterranean). – Journal of Iberian Geology 46 (2):195-207.

Helicina weyrauchi

The journal Malacologia just published a paper by Ampuero & Ramirez about Peruvian Helicinidae. “The original description of Helicina weyrauchi Haas, 1948, was based on shell material, as is the case for several helicinids in South America. We redescribe the species based on freshly collected material and provide the first anatomical description of a member of Heli- cinidae from northern Peru. The shell is characteristically white, with the first three whorls dark yellow; mantle with irregular dark spots on the dorsal surface, two pairs of odontophore cartilages and a narrow middle one. The male reproductive system consists of a prostate with glandular and collector regions, while the female reproductive system has a small and ovoid seminal receptacle, elongated provaginal sac with irregular projections with its stalk joining mesially, and oviduct aperture in the cloaca, near the mantle border. Records of H. weyrauchi are limited to the seasonally dry tropical forest of the Marañón River, which might indicate that this species is endemic to this ecosystem”.

The paper contains also information about the anatomy, which might be useful to compare to other species and might help to understand this poorly known group in South America.

Reference:
Ampuero, A. & Ramírez, R., 2020. Redescription of Helicina weyrauchi Haas, 1948 (Helicinidae) from the Marañón Dry Forest of Northern Peru. – Malacologia 63(1): 21-31.

Puerto Rican Polygyra

 

Freshly pressed, a note by Charles & Lenoble on Polygyra. “Polygyra cereolus (Megerle von Mühlfeld, 1816) is a small air-breathing snail originating in Florida, which is considered as an invasive species and is reported from a wide area in the south of the United States to Mexico and in some in some Caribbean Islands, Hawaii, Spain and the Arabian peninsula. Here we report the observation of this species in Puerto Rico”.

Unfortunately another report on an invasive species spreading.

Reference:
Charles, L. & Lenoble, A., 2020. Confirmation of Polygyra cereolus (Gastropoda: Polygyridae) in Puerto Rico, Greater Antilles. – Novitates Caribaea 16: 159-163.

New Cuban Cerion species

Suárez & Fernández published a paper on this topic. Their abstract reads as follows: “Five new species from the genus Cerion Roding, 1878 (Gastropoda: Cerionidae) are described, been four of them from Holguín province, and one from Guantanamo province, increasing to 156 the number of species described for Cuba. As notable diagnostic characters are mentioned for Cerion orteai sp. nov., with type locality in Playa Baracutey, Ramón de Antillas, the presence of columellar teeth and a comparative taller parietal tooth; for Cerion naylae sp. nov., with type locality in Playa Carmona, Ramón de Antillas, the absence of ribs in the half of the shell; for Cerion espinosai sp. nov., with type locality in Playa Baracutey, Ramón de Antillas, the stair way adopted during insertion in suture; for Cerion moralespradoi sp. nov., with type locality in El Canto, Punta de Maisí, a rounded apex, and a bilobulate parietal tooth; and for Cerion harasewychi sp. nov., with type locality in Rafael Freyre, Gibara, a conch surface with unperceptible ribs. For all these species, data of radule and reproductive organs are given“.

Cuba is a well-research island, but this paper shows it is still possible to find novelties.

Reference:
Suárez, A. & Fernández, A., 2020. Descripción de cinco especies nuevas de Cerion (Mollusca: Pulmonata: Cerionidae) de la región Oriental de Cuba. – Novitates Caribaea 16: 80-97.

Predation on Pomacea eggs

We know that land snails are usually not very selective in their food choice. Fonseca & Sant’Anna showed this in a recent study; “This study investigated the predation of eggs of the apple snail Pomacea dolioides in Itacoatiara, Amazonas, Brazil. Predation was compared between rural and urban areas, period of day, shaded and unshaded clutches. In addition, we evaluated clutch height and the behaviour of predators. Between April 2017 and July 2018, 962 egg clutches were observed at different times of the day: 492 in rural areas with predation of 68 egg clutches and 470 in urban areas with predation of only 9 egg clutches. Significant differences were recorded for predation rate and differences were recorded for egg clutch height in the areas. In the rural areas, the most frequent predators during the day were ants Solenopsis invicta, Crematogaster cf. carinata and the most abundant were S. invicta, Wasmannia aff. iheringi and C. cf. carinata. During the night, S. invicta was the most frequent and abundant predator. In urban areas, the frequency of predation and abundance of S. invicta were higher during the day and night than those of other predators. Populations of P. dolioides in rural areas are more affected by egg predation, mostly by S. invicta and C. cf. carinata, and predatory behaviour depended on the species of the predator“.

Schermafbeelding 2020-08-09 om 12.40.22

As the study (and this picture) shows ants were the dominant predators. But interestingly also 2 land snails are mentioned, with Bulimulus in rural and Subulina in urban areas.

Reference:
Fonseca, A.M. & Sant’Anna, B.S., 2020. Predation on eggs of the apple snail Pomacea dolioides (Reeve, 1856) in rural and urban areas of the Amazon. – Marine and Freshwater Research 71: 662-669.

Corrections to Simone (2006)

When the book of Simone on Brazilian land and freshwater molluscs appeared in 2006, it became obvious that quite some errors occurred in the text. Nothing too serious, but for the perfectionists that taxonomists are supposed to be still a nuisance in some way or another.

During the course of the years, several errors have been rectified in literature. But Simone has published some correcting papers in his recent Malacopedia.

To begin with the most recent one (Simone, 2020c): “Two cases of problematic taxonomy of Brazilian Subulinidae are unveiled. The basis is the catalogue by Simone (2006). The first is Bulimulus regularis (Pfeiffer, 1852) (species 366), which was transferred to the subulinid genus Beckianum, a new combination. The other is a duality in the Leptinaria parana (Pilsbry, 1906) (species 682), which actually are two species: 1) Subulina parana Pilsbry, 1906; and 2) Leptinaria parana Pilsbry, 1926, both from Pará, Brazil. Details of these taxa are discussed, and a new correction of the catalogue is suggested“.

Schermafbeelding 2020-08-05 om 07.00.01

Schermafbeelding 2020-08-05 om 07.00.31

Another correction concerns a bivalve species (Simone, 2019: “Pisidium pulchellum (d’Orbigny, 1835), from Uruguay and region, is a secondary homonym of P. pulchellum Jenyns, 1831, from Europe. A new replacement name, Pisidium dorbignyi Clessin, 1879 was introduced and is the present correct name. The name P. dorbignyi must replace the P. pulchellum in Simone (2006: 301, species 1055) and the given figure must not be considered (it is of an European P. pulchellum). Brief comments and synonymic list are performed here, including a reproduction of the original figure of P. dorbignyi“.

Schermafbeelding 2020-08-05 om 07.10.30

Finally, in two papers (Simone, 2020a, b) corrections of names are given.

Schermafbeelding 2020-08-05 om 07.19.11

Schermafbeelding 2020-08-05 om 07.07.13

References:
Simone, L.R.L., 2019. The enigmatic case “Pisidium pulchellum” (Bivalvia, Sphaeridae). Malacopedia 2(2): 13-15.
Simone, L.R.L., 2020a. Genera ending in “-stoma” are neuter in gender: South American cases. Malacopedia 3(2): 10-12.
Simone, L.R.L., 2020b. Genera ending in “-opsis” and “-gaster” are feminine; and “-ceras” and “-soma” are neuter in gender: South American cases. – Malacopedia 3(3): 13-15.
Simone, L.R.L., 2020c. Two cases of problematic taxonomy in Brazilian Subulinidae (Gastropoda, Eupulmonata). – Malacopedia 3(4): 16-21.