Monthly Archives: July 2019

A new subulinid from Argentina

A paper that escaped my attention until now, is by Miquel & Jaime (2018) describing a new species from Argentina. “The presence of two Subulinidae living in the tropical region of Argentina is recorded: Nannobeliscus mariaisabelae spec. nov. and an indeterminated species of Leptinaria. N. mariaisabelae is characterized by turrited shell, radular formula 17+1+17 with tricuspid teeth, penis with verge and epiphallus (producing spermatophores); vagina long, with one medial bulb; ovoviviparous. Leptinaria spec. is known only for its small shell, conical, perforated, with strong axial ribs, columella not truncated, amber-yellowish“.

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Based on anatomical data the authors argue that Nannobeliscus deserves to be raised to generic status. The genus is thus known from Argentina and Central Peru (where is was described from by Weyrauch), but undoubtedly more taxa in intermediate regions may be grouped with it.
Reference:
Miquel, S.E. & Jaime, G.L., 2018. Subulinidae species from northern Argentina with description of a new species of Nannobeliscus Weyrauch (Gastropoda, Stylommatophora, Achatinoidea). Spixiana, 41: 1–7.

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New fossils from Argentina

Just published: a paper by Miquel on continental gastropods from Argentina. “A new genus and two new fossil species of continental gastropods from the upper part of the Irene Formation—which is probably Huayquerian–Montehermosian (early Pliocene) and is exposed in the Quequén Salado River (Buenos Aires Province, Argentina)—are described: the new genus and species of freshwater gastropod Argentisioliella pardignasi (Cochliopidae) and a new species of landsnail of the family Bulimulidae (Bocourtia (Kuschelenia?) bonariensis). Argentisioliella pardignasi is morphologically related to those described for the Pebas Formation of Pliocene age. The specimens have bulloid morphology, long and narrow aperture, with a channeled peristome and two folds in the columellar wall. This is the first description of similar snails of the Pebas and Irene formations. Bocourtia (Kuschelenia?) bonariensis is the most ancient record for the genus, being recorded far away from the area of its current distribution (northwest Argentina). The specimen is an internal cast, with more than three convex whorls and a large aperture. Its distribution would coincide with the final phase of the Mio–Pliocene climatic change, when numerous terrestrial gastropods of Patagonian and Pampean provenance disappeared. A well-conserved specimen of the terrestrial snail Austroborus (Strophocheilidae Pilsbry), showing an almost complete shell, with more than 4.5 convex whorls, last whorl and large aperture, was also recorded. In the study area, this genus was present during the Pleistocene and Holocene, living in restricted areas of Argentina and Uruguay, with a disjunctive and relictual distribution“.

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Always interesting to see how palaeontologists are able to read those fragments. In this case the connection between Central Argentina and Pebas, in northeastern Peru on the Amazonian side, is remarkable. Thus a short but interesting paper.

Reference:
Miquel, S.E., 2019. A new genus and two new species of fossil continental gastropods from the early Pliocene of Argentina (Mollusca). – Ameghiniana 56 (2): 187–194.

Galápagos Gastrocopta

A recent paper by Miquel & Brito focusses on Gastrocopta species from the Galápagos, already mentioned in a previous paper.
Their abstract is as follows “A revision of Gastrocopta from the Galápagos Islands (Ecuador) is made. Four new species from Pinzón, Santa Cruz and Floreana Islands are described; species previously known are redescribed and new locations are added. Gastrocopta (Gastrocopta) reibischi is revalidated through new records from Floreana, Isabela and San Bartolomé Islands. Shell shape and the number, morphology and disposition of the apertural barriers support the discrimination of the taxa. The species have cylindrical to pupoid shells; the number of apertural barriers –differentiated as lamellae, folds and nodulae – varies between 4 and 11, almost completely occluding the aperture in the more complex cases. These structures are: angular-parietal, infraparietal, supracolumellar, columellar, subcolumellar lamellae, and supernumerary, basal, infrapalatal, lower-palatal, interpalatal, upper-palatal and suprapalatal folds. In addition to this classic scheme, a supernumerary fold and a nodule are added. Calcareous concretions –pustulae – are found in several species, mainly located in the peristome. The aulacognathous jaw and radular dentition formulae of Gastrocopta (Gastrocopta) clausa and Gastrocopta (Gastrocopta) munita, are described and photographed for the first time“.

The new species are all belonging to the nominate subgenus, and have been named respectively G. (G.) aliciae, G. (G.) christinae, G. (G.) franki, and G. (G.) herrerai. This means that the number of Gastrocoptid species from this archipelago has doubled! As most research on this group so far has been limited to a few islands, further novelties are to be expected as a result of future work.

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Reference:
Miquel, S.E. & Brito, F.F., 2019. Taxonomy and distribution of species of Gastrocopta Wollaston 1878 (Mollusca: Gastropoda: Gastrocoptidae) from the Galápagos Islands (Ecuador). – Molluscan Research, 39: 265-279.

Shells and bones

Found by serendipity: a forensic medicine study on the association of terrestrial shells with a buried skeleton (Galvão et al., 2015). As this is the first report of such an association and the crime case was in Brazil, it seems apt to report here.

The abstract reads as follows: “Little is known regarding the scavenger fauna associated with buried human corpses, particularly in clandestine burials. We report the presence of 20 shells of the terrestrial snail Allopeas micra, within hollow bones of human remains buried for 5 years, during the process of collecting DNA material. The fact that a large number of shells of A. micra had been found in the corpse and in the crime scene supports the assumption that there was no attempt to remove the corpse from the area where the crime occurred. Despite this, our observations cannot be used to estimate the postmortem interval because there is no precise knowledge about the development of this species. This is the first record of a terrestrial snail associated with a human corpse and its role in this forensic medicine case“.

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One of the co-authors was Luiz Simone, who also made the identification of the shells. Earlier studies on forensic malacology were focussed on marine species, and so this was an interesting case.

Reference:
Galvão M. et al., 2015. Shells and bones: A forensic medicine study of the association of terrestrial snail Allopeas micra with buried human remains in Brazil. – Journal of Forensic Sciences 60: 1369-1372.

A new Peruvian Sultana

Just published: a new Peruvian species of Sultana, published by two Spanish authors, Ahuir and Torres.
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The species is described from northern Peru, Dept. Piura, near Huancabamba on the border with Ecuador. Unfortunately the picture given is quite dark, but it shows the characteristic pink lip and the white inside of the aperture well enough. The holotype will be deposited in the Paris museum.
Thanks to Philippe Bouchet who sent me the paper.

Reference:
Ahuir Galindo, J. & Torres Alba, J.S., 2019. One new terrestrial gastropod species from Peru. – Malacologia Mostra Mondiale, 104: 3-4.

Avoiding canopy gaps

Only now a paper turned up which was already published in 2014. Bloch & Stock reported on a Puerto Rican species from the Solaropsidae related to ecological research. Unfortunately the paper is text-only…

The abstract is “Because canopy gaps are characterized by elevated temperature and decreased humidity relative to closed-canopy forest, terrestrial gastropods may be exposed to greater desiccation stress in gaps than in undisturbed forest. We placed individuals of Caracolus caracolla at the edges of canopy gaps in montane forest in Puerto Rico and observed their movements. Individuals preferentially moved out of gaps except in one gap on the first night of the study, and the proportion of individuals recaptured inside gaps decreased over time. Individuals moved, on average, farther into forest than into gaps. Juveniles and adults responded similarly. These results suggest that C. caracolla actively avoids canopy gaps, and that its activity and ability to disperse are restricted in a post-disturbance environment“.

Reference:
Bloch, C.P. & Stock, M., 2014. Avoidance of Canopy Gaps by a Common Land Snail, Caracolus caracolla (L.), in Montane Forest in Puerto Rico. – Caribbean Naturalist, 8: 1-13.

Rediscovered Bermuda species

When we consider Bermuda on the outskirts of the Neotropics, this information might be relevant:

Bermuda land snail: An animal ‘back from the dead’

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Thousands of critically endangered snails have been released into the wild after being rescued from the edge of extinction, with a little help from a British zoo.

The greater Bermuda land snail was thought to have disappeared for many years until an empty shell turned up in the territory’s capital city, Hamilton.

Live snails were then found among litter in a nearby alleyway.

Some were flown to Chester Zoo for a unique breeding programme.

More than 4,000 snails raised at the zoo have now been taken back to the island and released.

Many more captive snails will soon be returned to their homeland to help give the species a new lease of life.

Mark Outerbridge, a wildlife ecologist for the Bermuda government, said the snail was a “Lazarus species”, which was considered extinct not so long ago.

Then, in 2014, a man walked into his office in the capital, Hamilton, holding a fresh snail shell.

 

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“It turned out that, yes, this was in fact the greater Bermuda land snail, a species that we thought had gone extinct 40 years earlier,” he said.

“He came back the next day with a fresh one, a live one in his hand, and that’s how I was thrust into this conservation project.”

A small but thriving population of land snails was discovered behind a restaurant. The gastropods were living among litter – specifically inside thrown-away plastic bags – in a “dank wet alley”, surrounded by four-storey buildings.

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Water dripping from air conditioning units had created an environment where the animals could survive unnoticed.

“It turned out that the plastic bags were one of the favourite places for these snails to hang out, because of course it retained the moisture the best – and the snails are very vulnerable to drying out,” said Dr Outerbridge.

“And when we started picking up these plastic bags and unfolding them – literally they contained hundreds of juveniles and hatchling-sized snails.”

Some of the hatchlings were taken into captivity for breeding. Their offspring were later sent to Chester Zoo and the Zoological Society of London, where scientists were able to establish colonies.

It turns out that the snails are prolific breeders in captivity, with thousands of snails bred in a matter of years.

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“At the last count we’ve got somewhere around 13,000 snails – we’ve probably got more than that, they’ve had a lot of babies since then,” said Amber Flewitt, of Chester Zoo, who cares for the snails.

The secret of breeding success, she said, was nice soil and their favourite foods, which include sweet potato and lettuce.

Thousands of the Chester Zoo snails have now been sent back to Bermuda for release in nature reserves.

The snails are thought to be doing well in their new home.

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Dr Gerardo Garcia of Chester Zoo said that, following three years of intensive work, the zoo was proud to see the snails heading home.

“This is an animal that has been on this planet for a very long time and we simply weren’t prepared to sit back and watch them become lost forever when we knew we might be able to provide a lifeline,” he said.

The greater Bermuda land snail is unique to Bermuda and is part of an ancient lineage of land snail that dates back in time over one million years.

Once abundant on the islands that make up the territory of Bermuda, the population went through a dramatic decline during the 20th Century after being preyed on by invading killer snails.

The snails have been released on a nature reserve on the northern Nonsuch Island, which has snail-friendly habitats and no evidence of the main predators that nearly caused the animal’s demise.

They will join a small wild population, estimated at a few hundred individuals. This makes the species more rare in the wild than the likes of the giant panda or mountain gorilla, according to Chester Zoo.

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Some captive individuals have been fitted with fluorescent tags to monitor their recovery in the wild.

“Not only did they escape the axe of extinction but they have rebounded so well in captivity through breeding that now what we’re doing is we’re identifying islands in Bermuda that don’t have the predators and reintroducing them to those islands, and our expectations are very high that they’ll do well,” said Dr Outerbridge.

In the case of this species, it was a matter of having to look literally under every rock and every log before writing the animal off, he added.

The original article, including some videos, can be found here.