Tag Archives: drymaeus

Colombian Stenostylus and Drymaeus

Freshly pressed: a paper on two genera from Colombia with description of new species. The following abstract is given: “The land snails of the genera Drymaeus Albers, 1850 and Stenostylus Pilsbry, 1898, both belonging to the family Bulimulidae, and occurring within northwestern South America are revised and notes on their distribution are given. 78 species of Drymaeus and two of Stenostylus are herein confirmed from Colombia, and are illustrated for comparison. Six new (sub)species are described: Drymaeus (Drymaeus) denticulus, D. (D.) duplexannulus, D. (D.) felix restrepoensis, D. (D.) iniurius, D. (D.) intermissus, D. (D.) luciensis.”

5DrymaeusCOL

The abstract continues: “Drymaeus flexuosus megas Pilsbry, 1944 is now upgraded to species level. A lectotype is designated for Drymaeus roseatus montanus Pilsbry, 1901.
The following nominal taxa are herein synonymised: Bulimus antioquiensis L. Pfeiffer, 1855 = B. baranguillanus L. Pfeiffer, 1853; Bulimus hachensis Reeve, 1850 = B. virgo Lea, 1838 = B. columbianus Lea, 1838; Drymaeus eversus alata Piaget, 1914 = Drymaeus eversus subula Piaget, 1914 = Bulimus violaceus Mousson, 1873 = B. confluens L. Pfeiffer, 1855; Drymaeus cantatus medinanus Pilsbry, 1935 = D. tusagasuganus Pilsbry, 1935 = Bulimulus (Drymaeus) plicatoliratus da Costa, 1898 = Bulimus convexus L. Pfeiffer, 1855; Drymaeus fallax chicoensis Breure, 1977 = Bulimus fallax L. Pfeiffer, 1853; Bulimus trivittatus Mousson, 1869 = B. felix L. Pfeiffer, 1862; Bulimus andicola L. Pfeiffer, 1847 = B. multilineatus Say, 1825; Bulimulus (Drymaeus) comis Preston, 1907 = Bulimus pealianus Lea, 1838; Drymaeus incognita da Costa, 1907 = D. bellus da Costa, 1906 = D. blandi Pilsbry, 1898 = Bulimulus (Drymaeus) smithii da Costa, 1898.
For the following species, precise localities are given for the first time: Drymaeus (Drymaeus) angusta da Costa, 1906, D. (D.) auris (L. Pfeiffer, 1866), D. (D.) baranguillanus (L. Pfeiffer 1853), D. (D.) cognatus Pilsbry, 1901, D. (D.) geometricus (L. Pfeiffer 1846), D. (D.) inclinatus (L. Pfeiffer 1862), D. (D.) spadiceus da Costa, 1906, D. (Mesembrinus) koppelli (G.B. Sowerby III, 1892), D. (M.) muliebris (Reeve 1849).
Newly recorded for the Colombian malacofauna are the following five taxa: Drymaeus (Drymaeus) fordii Pilsbry, 1898, D. (D.) glaucostomus (Albers, 1852), D. (D.) volsus Fulton, 1907, D. (Mesembrinus) interruptus (Preston, 1909).
The following 27 taxa are excluded from the Colombian fauna as we consider them based on erroneous or doubtful records: Stenostylus meleagris (L. Pfeiffer, 1853), Drymaeus (Drymaeus) attenuatus (L. Pfeiffer, 1853), D. (D.) chimborasensis (Reeve, 1848), D. (D.) edmuelleri (Albers, 1854), D. (D.) linostoma (d’Orbigny, 1835), D. (D.) membielinus (Crosse, 1867), D. (D.) phryne (L. Pfeiffer, 1863), D. (D.) poecilus (d’Orbigny, 1835), D. (D.) protractus (L. Pfeiffer, 1855), D. (D.) rugistriatus Haas, 1952, D. (D.) strigatus (Sowerby, 1833), D. (D.) subinterruptus (L. Pfeiffer, 1853), D. (Mesembrinus) cactivorus (Broderip, 1832), D. (M.) deshayesi (L. Pfeiffer, 1845), D. (M.) dubius (L. Pfeiffer, 1853), D. (M.) flavidus (Menke, 1829), D. (M.) granadensis (L. Pfeiffer, 1848), D. (M.) liliaceus (Férussac, 1821), D. (M.) loxanus (Higgins, 1872), D. (M.) manupictus (Reeve, 1848), D. (M.) multifasciatus (Lamarck, 1822), D. (M.) nitidus (Broderip, 1832), D. (M.) pertristis Pilsbry, 1898, D. (M.) pervariabilis (L. Pfeiffer, 1853), D. (M.) studeri (L. Pfeiffer, 1847), D. (M.) translucens (Broderip, 1832)“.

The paper includes distribution maps for most species and a brief analysis of the fact that a number of species have not been recorded again after their initial collection.

Reference:
Breure, A.S.H. & Borrero, F.J., 2019. A review of Stenostylus Pilsbry, 1898 and Drymaeus Albers, 1850 (Mollusca: Gastropoda: Orthalicoidea: Bulimulidae) from Colombia, with description of new species. – Folia conchyliologica, 52: 1-79

A misidentified prey

In 2002 R. Williams published a brief note on a bird, the Scaled Fruiteater Ampeliodes tschudii, which had been observed near Tandayapa in Ecuador with a snail in its beak.

 

According to information given to him by a third person, only two species of terrestrial snail were living in that area: “the arboreal Plekocheilus sp. and a large terrestrial form in the family Pleurodontidae [now Labyrinthidae]”. Mr. Williams concluded that it must have been the Plekocheilus species that was caught by the bird.

Apart from the obvious errors in the sentence quoted above (both snails are terrestrial, and Plekocheilus species are not truly arboreal), it is clear from the picture provided in the note and copied above that the prey was misidentified. The shell in the bird’s beak look definitely like a Drymaeus species and the most likely candidate is Drymaeus aequatorianus (E.A. Smith, 1877) which is known from that region.

Reference:
Williams, R.S.R., 2002. Consumption of arboreal snails by Scaled Fruiteater Ampeliodes tschudii. – Cotinga, 18: 100.

Drymaeus dormani

Bill Frank was kind enough to send me some photos of Drymaeus dormani (W.G. Binney, 1857) from near Jacksonville, Florida.

His story in text is “…I then drove down to International Golf Parkway (AKA Nine Mile Road) to go into Twelve Mile Swamp and look for Drymaeus dormani. During my last four or five trips there I was unable to find any Drymaeus at all (living or dead). Again today it looked like I was going to get skunked but finally spotted a  decent sized live Drymaeus on a palm frond about ten feet above the ground. I tried getting it with my rake but there was no hope. I went back to the car and got my twelve foot long net and scooped it out of the tree. Ever since the last hurricane hit, which devastated Twelve Mile Swamp, Drymaeus are nearly impossible to find there. After the hurricane they cut the palm/palmetto way back from the road and since that time have periodically come back to make sure they stay trimmed back. I’m sure that there are plenty of Drymaeus in the swamp away from the road but I’m not brave enough to look just wearing shorts and tennis shoes knowing that there are venomous snakes. It’s dangerous enough just walking along the road looking for snails with cars speeding by just a few feet away – never mind the snakes that come out of the swamp to lay in the swale. Ever since I stepped on a Pygmy Rattlesnake there a few years back I’m a lot more careful than I formerly was.

Today’s Drymaeus is a real basket case having a pitiful looking shell and a lost eyestalk which appears to be regenerating. A real veteran”.

New Drymaeus from Peru

Just published: a paper on Peruvian Drymaeus species with description of a new species by Mogollón & Breure.

The abstract reads: “Critical remarks are made on Drymaeus species, reported from Peru in a study on land snails from National Parks at the eastern side of the Andes. Four of these species (Dry­maeus multilineatus, D. coniformis, D. glaucostomus, all known from Venezuela or Central America, and D. geomet­ricus, known from Colombia) appear to be misidentified as Peruvian species, which thus may lead to incorrect biogeographical interpretations. Correct identifications are given for all the disputed Drymaeus species. Bulimulus (Bulimu­lus) inconspicuus F. Haas, 1949, is now transferred to Dry­maeus (Mesembrinus). Additionaly, a new species, Drymae­us (Drymaeus) verecundus Breure & Mogollón, is described”.

Schermafbeelding 2019-04-07 om 11.22.00

The new species was found near Iquitos in NE Peru, and the type material has been deposited in the Brussels and Leiden museums.

Reference:
Mogollón, V. & Breure, A.S.H., 2019. Notes on Drymaeus species from Peru (Mollusca, Gastropoda, Bulimulidae), and description of a new species. – Basteria, 83: 13-18.

New Brazilian species

Recently published, Simone & Do Amaral studied snails collected on islands off the Brazilian coast and discovered new species.

Schermafbeelding 2018-11-17 om 14.58.23

Their abstracts is as follows: “Three new species of Bulimulidae (Gastropoda, Pulmonata) are described, each one endemic to a different island off the São Paulo coast, showing a high degree of endemicity of these islands in terrestrial malacofauna. Drymaeus castilhensis occurs on Castilho Island, it is mainly characterised by the strong axial dark spots in the shell or in being totally pale beige, penis elongated, lacking any inner chambers or glands, and double ducts of albumen gland. Drymaeus micropyrus occurs on Queimada Pequena Island, it is mainly characterised by greenish-cream shell, with narrow axial spots, and single duct of albumen gland. Bulimulus sula is from Alcatrazes Island, its main features include a relatively cylindrical, featureless shell, bilobed penis and, mainly and remarkably, a genital appendix that looks like a small accessory penis. These three species are described and compared with similar species, and accounts on their biogeography”.

Schermafbeelding 2018-11-17 om 14.59.00

The two species of Drymaeus, if presented as shells only and without locality data, are so similar that would have doubted them to be two different taxa. But the anatomical differences evidently show that cannot be conspecific. Also the Bulimulus species is anatomically peculiar with the reported “small accessory penis”.

Reference:
Simone, L.R.L. & Amaral, V.S. do, 2018. Insular life: new endemic species from São Paulo oceanic islands, Brazil (Pulmonata, Bulimulidae), as example of endemicity. – Journal of Conchology, 43(2): 167-187.

Photo of the day (173): Drymaeus

The group ‘Speurneuzen’ makes nearly every week a hike on the Island of Curaçao, usually to look for cultural-historical objects, but always to enjoy nature. This week they followed a new trail made by ‘Uniek Curaçao’ from Fort Kloof to Ascuncion. From their photo report I show a small batch of Drymaeus elongatus on a Wayaca tree.

The picture was made by Fred Chumaceiro.

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.