Tag Archives: ecology

Drymaeus tripictus ecology

Zaidett Barrientos have made an important contribution to the ecology of Neotropical snails to study the ecology and biology of Drymaeus tripictus (Albers, 1857) in Costa Rica. The abstract of the recent paper is as follows: “Very little is known about the ecology and biology of Drymaeus tripictus, an extremely rare and endemic land snail species from Costa Rican highlands. I studied the ecology and reproductive biology of D. tripictus from April 2009 through June 2010 in an old forest, a young forest and a Cupressus lusitanica plantation in central Costa Rica. Every three months I visited each habitat and collected specimens in 20 random sampling plots (3×3 m2 each). I observed the snail’s activity and microhabitat preference in the field, and in the labora- tory I recorded high definition videos of its mating behavior and analyzed reproductive morphology with light microscopy. The snail is more abundant in the old forest (0.017 ind./m2) and prefers leaves with little epiphyllous cover (0-25 % cover, chi-square test, p <0.0001). During the dry season the snails become active between 20:00 pm and 8:00 am (chi-square = 22.65, df=3, p < 0.0001); they are inactive mainly during the afternoon (11:00 am to 16:59 pm). I found active individuals mostly on the upper side of leaves, where they feed (Chi-square =6.76, df=1, p = 0.0093). Mating is unilateral, by shell mounting, with cryptic phallus intromission and without role switching or multiple mating. Its reproductive system is morphologically similar to that of Drymaeus costaricensis. Mating behavior is as expected for snails with high-spired shells, except for the lack of role switching. The density of D. tripictus is low even when compared with other endangered bulimulids”.

schermafbeelding-2016-11-30-om-15-42-37

A very interesting paper, which I had the pleasure to review as a draft (although not acknowledged).

Reference:
Barrientos, Z., 2016. Reproductive system, mating behavior and basic ecology of an extremely rare tropical snail: Drymaeus tripictus (Stylommatophora: Bulimulidae). – Revista de Biología Tropical, 64(1): 55–68.

Ecology of Costa Rican Drymaeus

Recently a very interesting paper has been published by Zaidett Barrientos (2016), describing the genitalia, mating behaviour and providing ecological data of the Costa Rican species Drymaeus tripictus (Albers, 1857).

The abstract reads “Very little is known about the ecology and biology of Drymaeus tripictus, an extremely rare and endemic land snail species from Costa Rican highlands. I studied the ecology and reproductive biology of D. tripictus from April 2009 through June 2010 in an old forest, a young forest and a Cupressus lusitanica plantation in central Costa Rica. Every three months I visited each habitat and collected specimens in 20 random sampling plots (3×3 m2 each). I observed the snail’s activity and microhabitat preference in the field, and in the laboratory I recorded high definition videos of its mating behavior and analyzed reproductive morphology with light microscopy. The snail is more abundant in the old forest (0.017 ind./m2) and prefers leaves with little epiphyllous cover (0-25 % cover, chi-square test, p <0.0001). During the dry season the snails become active between 20:00 pm and 8:00 am (chi-square = 22.65, df=3, p < 0.0001); they are inactive mainly during the afternoon (11:00 am to 16:59 pm). I found active individuals mostly on the upper side of leaves, where they feed (Chi-square =6.76, df=1, p = 0.0093). Mating is unilateral, by shell mounting, with cryptic phallus intromission and without role switching or multiple mating. Its reproductive system is morphologically similar to that of Drymaeus costari- censis. Mating behavior is as expected for snails with high-spired shells, except for the lack of role switching. The density of D. tripictus is low even when compared with other endangered bulimulids”.

Schermafbeelding 2016-06-22 om 12.27.02

Supplementary files on the journal’s website are supposed to be videos of the mating, but these were unavailable at the time of writing.

Reference:
Barrientos, Z., 2016. Reproductive system, mating behavior and basic ecology of an extremely rare tropical snail: Drymaeus tripictus (Stylommatophora: Bulimulidae). – Revista  de Biologia Tropical 64 (1): 55–68.

New paper published

Together with my colleague Corey Whisson, just published:

W&B2016a

A paper with a description of one new species is nothing to be taken too serious, but we are proud to present a novel way of (non-)dissection to study the genitalia: applying micro-CT and reconstruction with dedicated software. As far as we know this is one of the first times this method is applied to (land) molluscs in the context of describing a new species.

W&B2016b

Although the results presented here are satisfying, it is not necessarily a quick method and it is also quite laborious. However, in the case of a single or just a few specimens, this may be an alternative for destructive dissection. In this paper we show it as a ‘proof of principle’ for the application of this method.

Reference:
Whisson, C.S. & A.S.H. Breure, 2016. A new species of Bothriembryon (Mollusca, Gastropoda, Bothriembryontidae) from south-easternmost Western Australia. — ZooKeys 581: 127–140.

Field observations on Curacao

Just appeared: a paper by Gerard van Buurt with field observations and new records on the malacofauna of Curacao. Especially the ecological observations are very interesting and a new hypothesis is formulated which may explain the disjunct distribution of Drymaeus elongatus on the island.

Buurt2016_1

The abstract reads: “Currently 31 species of terrestrial snails are known from Curaçao, 28 of these are indigenous. The taxonomy of Curaçao land snails has been studied quite well. An inventory of species and subspecies exists. About their ecology however much less is known. The influence of salt spray from the sea on the distribution of some species is discussed. By observing snails in the field some conclusions about their ecology have been reached; these and some further assumptions are hereby presented. Three of the larger species of indigenous snails are discussed. These are Cerion uva, Drymaeus elongatus and Tudora megacheilos. The introduced snails Bulimulus guadalupensis, Zachrysia provisoria and Achatina fulica (= Lissachatina fulica) are briefly mentioned; the latter two are new records for Curaçao”.

Buurt2016_2

Reference:
Buurt, G. van, 2016. Field observations on some Curacao landsnails, and new records for its fauna. – Folia Conchyliologica 34: 1–16. Link to PDF

 

Various new papers

Several new papers on Neotropical snails did appear recently, with emphasis on Cuba and Brazil (decidedly the most active malacological societies).

Cuban papers were published in a new issue of the journal ‘Solenodon’ and focus mainly on Cerionidae.

Suárez studied the reproductive cycle of Cerion mumia chrysalis Férrusac, 1837. “Gonads of 144 mature specimens of Cerion mumia chrysalis were examined. Between January-December, 2012 were collected 12 specimens per month. Two reproductive cycles were recognized, one from January to April, and another from July to September. Both male and female reproductive cells were observed inside the acini, which defines the species as hermaphrodite. During May-June and subsequently in October-November no follicular activity was observed. In December, the acini decreased notably in size”.

Suarez 2015

Suárez et al. published on the effect of hurricanes on molluscs. “Data about the conservation status on mollusk populations of Cerion dimidiatum Pfeiffer, C. scalarinum Pfeiffer and Gundlach, C. torrei moralesi Clench and Aguayo, C. p. paucicostatum Torre, and C. orientale Clench and Aguayo, local endemics from Eastern Cuba are given. Populations were affected by the hurricanes hazard, been obtained values of 0.4 ind/m2; 0. 37 ind/m2; 0.04 ind/m2; 0.16 ind/m2 and 0.03 ind/m2 respectively”.

Two papers related to distribution. Fernández et al. (2015a) published on “the geographic distribution range of Cerion saetiae Sánchez Roig, 1948 was widened, with two new records: Playita de Fidel in Saetía key and Baracutey beach from El Ramón de Antilla peninsula. It presence was corroborated at type locality. Abundance and lineal dimensions variability of shell are explained”.

Fernandez et al 2015a

Fernández et al. (2015b) made “a study about terrestrial mollusks in altitudinal levels and different rocky substrata in Sierra de Nipe. Thirty new records from Sierra of Nipe and adjacent heights are presented. Twenty-six localities were visited; among them seven on serpentine rocks between 400-1000 masl, 19 localities on calcareous substratum from 100- 400 masl and eight localities were taking from published papers. One hundred fourteen species were recorded, constituting 8.2% of the Cuban fauna thereby reaching the second more diverse place in Cuba, after Viñales; therefore representing 57.3% of those known species at Nipe-Sagua-Baracoa. On calcareous substratum 113 species were recorded while on serpentine were 25, most of them also on calcareous soils, except Caracolus n. sp. Part of this terrestrial mollusks “hotspot” is protected by the National Park Mensura-Piloto”.

Fernandez et al 2015b

Finally, I like to mention a recent paper by Simone on the bulimulid genus Kora, with description of new species. The abstract reads “Three new species of the recently described genus Kora are described, based on dry material collected in caverniculous and adjacent environments. Kora terrea, from Presidente Olegdrio, MG, is characterized by spotted pigmentation; projected, wide outer lip, and pointed spire. Kora nigra, from Carinhanha, BA, is characterized by dark-brown color, elliptical outline, and rounded, narrow aperture. Kora iracema, from Sao Desidério, BA, is characterized by very ample, projected outer lip, wide spire and white coloration. A new occurrence of the type species, Kora corallina, is reported, from Carinhanha, BA, expanding its geographic distribution ~200km towards southwest. Species of the genus Kora have been shown to be restricted to semi-dry, caatinga environment, restricted to south region of Northeast Brazilian region, and north of Southeast region”.

Simone 2015

References:
Fernández, A., Franke, S., Suárez, A. & Hernández, I., 2015a. Registros nuevos, abundancia y morfometría de Cerion saetiae (Mollusca: Pulmonata) en la provincia Holguín, Cuba. – Solenodon 12: 28-32.
Fernández, A., Frenke, S., Espinosa, J., Reyes, E., Sigaretta, S., Matos, A. & Rodríguez, Y., 2015b. Moluscos terrestres (Mollusca: Gastropoda) en Sierra de Nipe y alturas adyacentes, Cuba. – Solenodon 12: 38-56.
Simone, L.R.L., 2015. Three new species of Kora (Pulmonata, Orthalicidae) from Bahia and Minas Gerais, Brazil. – Journal of Conchology 42: 51-56.
Suárez, A., 2015. Ciclo reproductivo de Cerion mumia chrysalis (Pulmonata: Stylommatophora: Cerionidae). – Solenodon 12: 21-27.
Suárez, A., Hernández, I., Morales, A. & Fernández, A., 2015. Densidad de algunas poblaciones de ceriónidos (Mollusca: Gastropoda: Cerionidae) de la región oriental de Cuba, recientemente afectada por huracanes. – Solenodon 12: 33-37.

[The Solenodon issue is available here]

Photo of the day (163): Polydontes

These are some additional photos by Rolf Nijsse, kindly transmitted by Herman Cremers, taken during a recent trip to Puerto Rico, Luquillo Experimental Forest. They show Polydontes acutangula (Burrow, 1815), which is very similar to the species shown here but may be distinguished by its dark rim of the foot. N.B.: A recent preliminary report on the terrestrial snails of the island by Robinson & Field mentions this species as Parthena acutangula.

P1130654

P1130661

The classification of this group of snails (currently in Pleurodontidae) is to a large extent based on anatomical differences (see Wurtz, 1955).

The Luquillo Experimental Forest is a field station for ecological work, and snails have been the subject already for decades. A review may be found here.

Reference:
Wurtz, C.B. (1955). The American Camaenidae (Mollusca: Pulmonata). – Proceedings of the Natural Sciences of Philadelphia 107: 99-143. [http://www.jstor.org/stable/4064483]

Photo of the day (162): Drymaeus

On Curaçao, Drymaeus virgulatus (Férussac, 1821) is occurring in a selected number of areas. One of these is the Christoffelpark. These snails are usually found as clusters on the stem of trees, in this case along a ‘rooi’ in the Zorgvlied section of this nature protection park.

01 Track Zorgvlied - Roi NE Seru Pretu 150122 K93

 

Drymaeus

Thanks to François van der Hoeven and his members of the Workgroup Archeologie, for their interesting weekly trips over the island, and the well-illustrated reports on them.