Tag Archives: biogeography

Diversity of molluscs in Tamaulipas, NE Mexico

Correa-Sandoval et al. (2017) published new data on the malacofauna of the Edo. Tamaulipas in northeastern Mexico. The abstract reads “Diversity and biogeography of Mexican terrestrial gastropods is poorly known. The terrestrial mollusks of the Sierra of Tamaulipas were surveyed from October 1988 to November 2005. A total of 482 samples were obtained from 30 localities, characterized with different vegetation types. Thirty-one genera and 46 species belonging to 18 families are recorded. The primary zoogeographical relationships are characterized by the presence of neotropical and neartic affinities (17 species: 37%) and the endemic taxa (11 species: 24%). The family Spiraxidae has the largest number of endemic species (6). The biogeographical value in this area is 3.78”.

Given the excellent work of Thompson with his checklist of Central American non-marine molluscs, I cannot say that I concur with the first sentence of the abstract. But this paper fits in the general picture of our current knowledge; there is a detailed species lists but not an overview of sampled localities.

Correa-Sandoval, A. et al., 2017. Diversidad y zoogeografia de los moluscos terrestres de la Sierra de Tamaulipas, Mexico. – Acta Zoologica Mexicana Nueva Serie, 33 (1):76-88.

Urocoptidae revisited

Uit de Weerd et al. (2016) have published a paper on the evolutionary history of biogeography of the land snail family Urocoptidae. It is a sequel following previous papers of Uit de Weerd dealing with the Caribbean region.

The authors reconstructed the phylogeny of Urocoptidae based on multi-locus (partial 28S, H3 and COI sequences) analyses (MrBayes, BEAST, GARLI) of 65 species, representing 44 recognized genera. Biogeographical analyses of a subset of the time-calibrated BEAST trees were made both with (DEC and DEC+J analysis in BioGeoBEARS) and without (S-DIVA in RASP) palaeo-geographical assumptions. In the DEC and DEC+J analyses we examined the effect of different settings for dispersal between directly connected areas relative to that between areas without direct land connection. Urocoptidae has been present on the Greater Antilles Arc from at least Middle Eocene onwards. Morphologically diverse and previously unrecognized clades evolved on most Caribbean (palaeo)islands. Jamaica was colonized at least twice. Dispersal multiplier matrices with moderately constrained dispersal between areas without direct land connections describe the phylogeographical history of the family with higher DEC and DEC+J lnL scores than uniform matrices. Urocoptids constitute an old element of the Greater Antillean biota, predating a proposed GAARlandia landspan connection to South America. The biogeographical history and evolution of Urocoptidae were shaped primarily by the geographical distribution of Caribbean landmasses, in combination with occasional oversea dispersal. Oversea dispersal allowed colonization of palaeogeographically isolated areas, such as Jamaica and present-day western Cuba, where presumably the absence of ecological competitors led to independent radiations into similar shell types. A follow-up paper will be dealing with the taxonomic consequences of this study.


With the representation of 44 genera out of the total 65 recognized genera within the family, this is a comprehensive molecular analysis. No other Caribbean family has been treated this way, thus this study provides unique insights and helps to test competing biogeographical theories about land snail distribution in this region.

Uit de Weerd, D.R., Robinson, D.G. & Rosenberg, G., 2016. Evolutionary and biogeographical history of the land snail family Urocoptidae (Gastropoda: Pulmonata) across the Caribbean region. – Journal of Biogeography (early online access) http://wileyonlinelibrary.com/journal/jbi | doi:10.1111/jbi.12692

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 biplicataCochlodina 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”.

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

Evolution and biogeography of Urocoptidae

Just published, the very interesting paper by Dennis Uit de Weerd et al. presents new data on the phylogenetics of the land snail family Urocoptidae. They also tested some biogeographical hypotheses using the phylogeny and present as results: “Urocoptidae has been present on the Greater Antilles Arc from at least Middle Eocene onwards. Morphologically diverse and previously unrecognized clades evolved on most Caribbean (palaeo)islands. Jamaica was colonized at least twice. Dispersal multiplier matrices with moderately constrained dispersal between areas without direct land connections describe the phylogeographical history of the family with higher DEC and DEC+J lnL scores than uniform matrices”.


As their main conclusions they present: “Urocoptids constitute an old element of the Greater Antillean biota, predating a proposed GAARlandia landspan connection to South America. The biogeographical history and evolution of Urocoptidae were shaped primarily by the geographical distribution of Caribbean landmasses, in combination with occasional oversea dispersal. Oversea dispersal allowed colonization of palaeogeographically isolated areas, such as Jamaica and presentday western Cuba, where presumably the absence of ecological competitors led to independent radiations into similar shell types”. In a future paper a taxonomic revision of the family and of the genus Brachypodella will be published.

Uit de Weerd, D., Robinson, D.G. & Rosenberg, G. (2016) Evolutionary and biogeographical history of the land snail family Urocoptidae (Gastropoda: Pulmonata) across the Caribbean region. – Journal of Biogeography [advanced access]: 1–15.

Conservation issues on Brazilian land snails

Ignacio Aguda-Padrón has recently published a suite of short communications on different conservation aspects of land snails in Brazil.

In a first paper (Agudo-Padrón, 2012a) he reviews briefly the effects of the introduction of the Giant African Snail on the native snail population. Abstract: A diagnostic about the conservation status of the Brazilian native land snails, severely threatened by human actions and attempts for the eradication of the invasive exotic mollusc species Achatina (Lissachatina) fulica (Bowdich, 1822) is presented. Purposely introduced in the country in 1988 for human food purposes (continental malacoculture), this species ended up being officially banned later in 2003, triggering hasty public actions, directly involving the “unprepared” Brazilian population through the means of social communication, aimed at their control and eradication of the environment. Consequence of this procedure, premature and alarmist, today many species of native and endemic terrestrial snails, poorly known scientifically, are under increased threat of extinction in Brazil and, very probably, in other South American countries.
The same data have been re-published in Agudo-Padrón (2012b).

In a second review (Agudo-Padrón, 2012c) he summarizes the available data on biogeography concerning snails in the southeastern part of Brazil and adjacent areas. Abstract: A preliminary diagnostic test summary balance sheet and rough on the marine and continental mollusc fauna, terrestrial and limnic/freshwater, occurring in the geopolitical region of the Southern Brazil and adjacent is presented. Result of extensive research work in the field and analysis of regional natural history reference generated off dilated bibliographic production, developed in the course of the last 13 years (1996~2009), aims to characterize and integral organization of their unique knowledge, emphasizing the major ecological and geographical factors that determine their presence, spatial location and occupancy of available environments. Parallels, the comparative results regarding the total numbers of species estimated for each of the portions of the territory geo-spatial components analyzed, the Brazilian states of Paraná (PR, 332), Santa Catarina (SC, 772), Rio Grande do Sul (RS, 492), and the neighboring countries of its southern Uruguay (373) and Argentina (535), members as a whole so-called Atlantic Slope region of the Southern Cone of South America, to the West of the Andes.

Finally, a recent publication summarizes the conservation status of terrestrial snails, both as recognized by the IUCN and by local Brazilian authorities (Agudo-Padrón, 2013).

Seemingly in consensus, if one accept that the same criteria have been used, it is remarkable that IUCN recognized a more severe category in six cases. In two cases no joint data are available and in two other cases their judgement of the situation is identical. Only in the case of Gonyostomus insularis the Brazilian verdict ranks this species in a higher category. One can only guess what is the different reasoning behind all this.

AGUDO-PADRÓN, A.I. 2012a. Dangerous brazilian environmental controversy involving exotic and native land snails. International Journal of Biology and Biological Sciences, 1(1): 1-4. Available online at:http://academeresearchjournals.org/journal/ijbbs/archive
AGUDO-PADRÓN, A.I. 2012b. Conservation situation of native land snails threatened by “actions for eradication” of exotic species in Brazil, South America. Biological Evidence, 2(1): 1-2. Available online at:http://bio.sophiapublisher.com/html-464-40-be
AGUDO-PADRÓN, A.I. 2012c. Mollusc fauna in the Atlantic Slope region of the Southern Cone of South America: a preliminary biogeographical interpretation. International Journal of Aquaculture, 2(4): 15-20. Available online at: http://bio.sophiapublisher.com/html-442-33-ija
AGUDO-PADRÓN, A.I. 2013. Effective knowledge and conservation of continental molluscs in Brazil, South America, with special emphasis in gastropods: the current situation. Journal of Biodiversity Management & Forestry, Henderson/ Nevada, 2(1): 1-2. Available online at:http://www.scitechnol.com/JBMF/JBMF-2-103.pdf

New taxa (30): Mexistrophia

The well-known specialist of Central American and Caribbean land shells, Fred Thompson, recently published two interesting papers. Today I mention only his paper on Cerionidae (Thompson, 2011); the other paper will follow shortly.

Cerionids are well-known from the Caribbean, where they occur at low elevations. During his extensive field work in Mexico, Thompson found shells in habitats and elevations that were uncharacteristic for Cerion, and he put them as indeterminable “Urocoptidae”. Closer study, also of the anatomy, revealed that these shells should be classified with the family Cerionidae. In this paper three new species are described within a new genus, Mexistrophia. This genus is now known to be distributed in the Mexican states Querétaro, Nuevo León and Hidalgo, and may be quite widespread once anatomical data become available to ascertain their identification.


The type species is M. reticulata, type locality Edo. Querétano, 1.0 km E Pinal de Amoles, 2150 m. Holotype UF 211128.
A second species, M. obsoleta, was found at a nearby location, 15.8 km by road SW Pinal de Amoles, 2585 m. Holotype UF 34298.
Finally, a third species, M. inexpectata, is described from Edo. Nuevo León, 0.5 km N El Refugio, 2360 m. Holotype UF 226407.
All species are narrow-range endemics and inhabit cool temperate conifer forests that are subject to seasonal frosts.

Biogeographically, it is interesting that this group is disjunct from the ‘true’ Cerion, occurring in the West Indies.

Thompson, F.G., 2011. Mexistrophia, a new genus of Cerionidae from Mexico (Gastropoda: Pulmonata: Urocoptoidea). – The Nautilus 125: 182-192.

Network for Neotropical Biogeography

Still in its infancies, a Network for Neotropical Biogeography is being formed now to stimulate scientific interaction and promote inter-disciplinary cooperation (among other aims).


Although so far the network seems to consist mainly of botanists, I hope it will reach its goal to stimulate contact between different fields of interest. Publications and images can be easily exchanged between interested scientists and probably lots of potential just need further to develop.

Good initiatives always need to be plugged, so here it goes.