Population dynamics of a Megalobulimus species

The recent study by Miranda & Fontanelle (2015) is a welcome addition to our knowledge of Megalobulimus species.

ABSTRACT. The population dynamics of Megalobulimus paranaguensis (Pilsbry & Ihering, 1900), a large and long-lived land gastropod from Brazil’s Southeast (Atlantic Forest) was studied between 2006 and 2009, at an urban park in the city of Santos, state of São Paulo. The study included biometry, weighing, and marking and recapture of adult individu- als. The variables obtained from specimens were correlated with the environmental variables of the study period. The survival rate of the adult snail population was 96.7%. Recruitment showed several peaks during the year, and was concentrated between April and August, except in 2009, when there was only one peak in August. Specimen abun- dance progressively increased from 2006 on, with a trend towards relative stability during that period. The condition factor remained relatively stable as well, decreasing from December to February. The potential evapotranspiration and precipitation influenced the number of captures, and the mean temperature influenced the condition factor. Megalobulimus paranaguensis goes through a period of dormancy in the tropical summer, which is between November and February, but remains active in the winter. The survival rate of M. paranaguensis was high, and may be the result of having its annual cycle synchronized with the tropical climate of the Atlantic forest.

Reference:
Miranda, M.S. & Fontenelle, J.H., 2015. Population dynamics of Megalobulimus paranaguensis (Gastropoda: Pulmonata) in the southeast coast of Brazil. – Zoologia 32 (6): 463–468.
Available at http://dx.doi.org/10.1590/S1984-46702015000600005

Passive dispersal mechanisms

An interesting paper just appeared about passive snail dispersal mechanisms. Simonová et al. (2016) carried out an experiment with European forest snails and birds in an aviary to find out about survival rates of snails being eaten by birds or by being carried away by attachment to the bird’s body.

Their abstract is: “It is well known that land snails can be dispersed by birds, both by attachment to the body (ectozoochory) and by passing intact and alive through the bird’s digestive tract (endozoochory). Endozoochory has, however, only been recorded for very small species. We examined the possibility that larger species (up to c. 17 mm in maximum shell dimension) could survive passage through a bird’s digestive system. Live Alinda biplicata, Cochlodina laminata (both Clausiliidae) and Discus rotundatus (Discidae) were fed to 10 bird species (Corvidae, Turdidae, Sturnidae and Columbidae) in 14 experimental trials. Of 720 snails offered, 14 passed intact through the birds, of which nine were alive (eight clausiliids and one D. rotundatus); thus more than 1% of all snails offered survived ingestion. In an additional experiment, some A. biplicata and C. laminata remained attached to birds’ legs by pedal adhesion in simulated flight trials where the birds’ legs oscillated at the maximum rate achieved during flight”. It must be noted that faces were collected between 20 and 26h after offering the snails to the birds.

These results are a pointer to the possibility of passive dispersal of these species. No doubt the same applies for species of snails and birds in other parts of the world. With regard to the Neotropical Realm, this mechanism could be a hypothesis in those cases where geology makes vicariance unlikely. However, for long-distance dispersal survival rates after prolonged times should be investigated. This as addition to the final conclusion of the paper: “More experiments with a wider range of snail and bird species are clearly desirable”.

Reference:
Simonová, J., Simon, O.P., Kapic, S., Nehasil, L. & Horsák, M., 2016. Medium-sized forest snails survive passage through birds’ digestive tract and adhere strongly to birds’ legs: more evidence for passive dispersal mechanisms. — Journal of Molluscan Studies (2016) 1–5. doi:10.1093/mollus/eyw005

Finally published…

Some manuscripts have a smooth flow from submission to publication, others have a lot of obstacles to overwin. Just published:

Initially submitted to Zoologische Mededelingen, journal of Natural Biodiversity Center, the manuscript had already a long history. At a certain moment in time the editor had lost all files, so I had to supply them again. Finally I received notice from the editor-in-chief in summer 2015 it was accepted and waiting to be printed. Early December 2015 I got notice the first proofs were expected in January. Imagine my dismay when during Christmas I received a mail from the deputy Director of Science, writing that the journal had been cancelled with immediate effect and all authors with accepted papers had to find another outlet.

After some deliberate thinking I decided to submit it to PeerJ, a journal not in common use with malacologists but I had some examples so I gave it a try. Naturally, I had to re-format a lot of things and after the reviews and re-submission the editor had some desired changes as well. But finally, it is here…

New fossil species from Argentina

Miquel & Rodriguez (2016) describe a fossil fauna found in southern Patagania with an interesting composition. One new genus and four new species are described.

The abstract is: “A remarkable fossil assemblage composed of five gastropod taxa is described from the Early Miocene of Santa Cruz (Patagonia, Argentina) in southernmost South America. The assemblage includes extinct and living genera South America, and on geographic distributions and represent background new information on spatial and across time distributions as well as identification of new taxa. A new taxon, Patagocharopa enigmatica n. gen. n. sp., is tentatively assigned to Charopidae. Gastrocopta patagonica n. sp. (Vertiginidae) represents the oldest record of Gastrocopta in Argentina and the southernmost record for the Americas. Punctum patagonicum n. sp. (Punctidae) represents the first record of Punctum for continental South America, and characterized by a protoconch with traces of axial costulae and a teleoconch with strong radial ribs. Zilchogyra miocenica n. sp. is the first Miocene record of the charopid genus Zilchogyra. Fragments of a possible Scolodonta (Scolodontidae) are recorded. Overall, the assemblage represents an important and useful paleoenvironmental tool. This fauna suggests that a more temperate and humid environment than today—with a more dense vegetation cover—was prevalent at this site during the Early Miocene”.

Reference:
Miquel, S.E. & Rodriguez, P.E., 2016. A novel late Early Miocene assemblage of terrestrial gastropods from Santa Cruz (Patagonia, Argentina). — Journal of Paleontology X: 1–14 (advance access).

New Tentacle issue

A new Tentacle issue is out and here I summarize the Neotropical land snail tids and bits found in there.

Espinosa & Bastardo provide information on the ecology, biology and conservation status of Coloniconcha prima Pilsbry, 1933. They found several populations which seemed healthy, one counting 449 individuals, and observed that this species uses a great variety of vascular plants for feeding and resting. Threats are the construction of (access) roads to crops and agricultural activities, illegal extraction of trees, human induced fires, and the replacement of former shaded coffee crops by short cycle crops like beets.

Fernández et al. report on 51 range-restricted species in the coastal zone of Holguín province, Cuba. They comprise the families Helicinidae (5), Pomatiidae (11), Urocoptidae (5), Cerionidae (21), Oleacinidae (1), Camaenidae [Pleurodontidae] (1), Cepolidae (6), Xanthonychidae (1).

Suárez et al. studied the occurrence and ecology of Cerion mumia hondanum Pilsbry, 1902 near the shore line at Bahia Honda, Cuba. They also report on observations on other species, e.g. they observed how Cerion species deposited their eggs in sand and found one species associated with the mangrove species Rhizophora mangle.

Herrera studied an endemic species of the Cuban Isla de la Juventus (formerly known in older literature as Isle of Pines), Pineria terebra Poey, 1851. This species has two subspecies, each with  very small areas of which the habitat is threatened by frequent forest fires.

Cavallari et al. summarize some recent papers which described several new species from Bahia State in Brazil. The diversity in this state seems rather exceptional and may be linked to three biomes being present: the Cerrado, the Caatinga and the Atlantic Forest.

Miranda & Pecora analyzed the population structure of both Achatina fulica and the native Megalobulimus paranaguaensis. Their conclusion is that the native snail is possibly most affected by environmental modifications and the efforts to control the African snail.

Agudo-Padron delivered two papers. One recording the first find of Achatina folic in the greater Porto Alegre area, part of the Pampas biome. In the second paper he reports on the malacofauna of Santa Catarina State, which now counts 150 terrestrial taxa. His figure shows some species from the ecological region of Itajai Valley.

Finally, Rodriguez et al. studied the diversity of terrestrial species in 16 municipalities in Rio de Janeiro State in Brazil. The most abundant species are shown in their figure:

The entire issue of Tentacle is available here.

References:
Agudo-Padrón, A.I., 2016a. Research and conservation of mollusks in Santa Catarina State, central southern Brasil, after 20 years of systematic activities. – Tentacle 24: 20–21.
Agudo-Padrón, A.I., 2016b. Conservation of endemic molluscs in the southernmost region of Brasil: first confirmed record of the alien snail Achatina folic in the Pampas biome. – Tentacle 24: 21–22.
Cavallari, D.C., Salvador, R.B. & Simone, L.R.L., 2016. A possible land snail diversity hotspot in Bahia State, Brasil. – Tentacle 24: 14–16.
Espinosa, A. & Bastardo, R.H., 2016. Conservation status of Coloniconcha prima (Gastropoda, Pleurodontidae). – Tentacle 24: 5–7.
Fernández, A., Franke, S. & Suárez, A., 2016. Restricted range species in the coastal zone of Holguín, Cuba: checklist and new records of priority species for conservation. – Tentacle 24: 7–10.
Herrera Uria, J., 2016. Conservation status of Pineria terebra Poey, 1851 (Gastropoda: Urocoptidae) from Isla de la Juventud, Cuba. – Tentacle 24: 12–13.
Miranda, M.S. & Pecora, I.L., 2016. Megalobulimus paranaguensis and Achatina fulica: a good model of the conservation of native fauna and interactions with alien species. – Tentacle 24: 19–20.
Rodrigues, P., Fernandez, M.A., Thiengo, S.C., Salgado, N.C. & Gomes, S.R., 2016. Diversity of terrestrial molluscs in urban areas and surrounding landscapes of Rio de Janeiro State, Brasil. – Tentacle 24: 39–41.
Suárez, A., Hernández, I. & Fernández, A., 2016. Conservation data on Cerion mumia hondanum (Mollusca: Pulmonata: Cerionidae) from Bahía Honda, Pinar del Rio, Cuba. – Tentacle 24: 10–12.

New species from Juan Fernandez Archipelago

Miquel & Araya (2015) recently published on new shells from the Juan Fernández Archipelago off the coast of Chile. This is the first addition since nearly a century ago. One species is new described, Neoparyphantoplsis crusoeana gen.n., sp.n.; one replacement name is introduced (Tornatellina juanfernandeziana), and five species are re-described.

Reference:
Miquel, S.E. & Araya, J.F., 2015. New records of terrestrial mollusks of the Juan Fernández Archipelago (Chile), with the description of a new genus and species of Charopidae. Archie für Molluskenkunde 144: 155-167.

Veronicellidae in Argentina

Santin & Miquel (2015) published recently on the family Veronicellidae in Argentina. Always a tricky family, thus it is a nice contribution to our knowledge of this fauna.

The abstract reads:

Reference:
Santin, R.A. & Miquel, S.E., 2015. Veronicellidae in Argentina: taxonomy, morphology and distribution. – Archiv für Molluskenkunde 144: 105–123.