Monthly Archives: August 2019

Ovachlamys in Brazil

Just published: a report that confirms the occurrence of a new invasive snail in this country. “The occurrence of the invasive non-native Asiatic jumping land snail Helicarionidae Ovachlamys fulgens (Gude, 1900) is finally confirmed by us in the southern Brazil region, specifically on the Santa Catarina State territory, from previous records available since the year 2013 “masked” under the identity of another species. This report increases to 27 the number of exotic continental molluscs confirmed in the State of Santa Catarina/ SC.“.

Schermafbeelding 2019-08-16 om 07.58.11

Not surprisingly the occurrences are mainly situated near the region where the port activities occur. I wouldn’t be surprised if these snail travel with sea containers, as the distribution of Bulimulus sp. suggests (ongoing research, unpublished data).

Reference:
Aguda-Padron, I., 2019. Confirmed occurrence of the invasive asiatic jumping land microsnail Helicarionidae Ovachlamys fulgens (Gude, 1900) in the Southern Brazil region. – Bioma (El Salvador) 5 (49): 11–15.

Advertisements

Veronicellids recharacterised

Just published: a paper by Rocha & D’ávila on the Veronicellid genera Latipes and Angustipes.

Schermafbeelding 2019-08-08 om 11.58.44

Their abstract is “The genera Angustipes Colosi, 1922 and Latipes Colosi, 1922 were originally proposed as “groups” within the genus Vaginulus Ferrussac, 1822, and since their establishment they have been variously considered valid or invalid until they gained the ultimate status of genus. The descriptions of both genera are general and broadly inclusive, and this fact has complicated taxonomic recognition. Additionally, incomplete descriptions and difficult identification of characteristics in the name-bearing type specimens demonstrate the need to revisit the species and revise the two genera. Herein, we broaden the description of Latipes erinaceus Colosi, 1922 with respect to the circulatory system, the radula, the jaw, the position of entry of the ligation duct in the bursa copulatrix in relation to the canal of the bursa, the origin of the muscle of the penial gland, along with the morphometric characteristics of the phallus, the penial gland, the pedal gland, and the bursa copulatrix. We also propose new differential diagnoses for the genera Angustipes and Latipes, limited to the essential characteristics that enable taxonomic recognition. Hence, we propose the assignment of the species L. erinaceus, Latipes rosilus (Thiele, 1927), Latipes ribeirensis (Thiele, 1927), and Latipes absumptus (Colosi, 1921) to the genus Angustipes, based on the presence of morpho- logical characteristics attributable to this genus, such as the phallus being short and conical; the bursa copulatrix being sessile or short, and lacking a head; the ligation duct inserted near the canal of the bursa; as well as on the similarity in phallus morphology with Angustipes difficilis Colosi, 1922, the type species of this genus“.

Schermafbeelding 2019-08-08 om 11.59.40

The family Veronicellidae is notoriously enigmatic due to the need to use anatomical charcters for classification. This paper is thus a welcome addition to the literature of this family.
Reference:
Rocha, C.A. & D’ávila, S., 2019. New Morphological Characterization of Latipes erinaceus (Gastropoda, Veronicellidae), Differential Diagnosis for the Genera Angustipes and Latipes, and Novel Combinations for Species of Latipes. – Zoological Science (Tokyo), 36 (3):231-241.

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.

Long distance dispersal

The malacofauna of oceanic islands often shows a high endemism, but the origin of the fauna is many times obscure. Hendriks et al. (2019) have published a paper on Borneo land snails that is interesting in this context.

Schermafbeelding 2019-08-08 om 11.00.55
The abstract reads as follows:
Aim: Islands are often hotspots of endemism due to their isolation, making colonization a rare event and hence facilitating allopatric speciation. Dispersal usually occurs between nearby locations according to a stepping-stone model. We aimed to reconstruct colonization and speciation processes in an endemic-rich system of land- based islands that does not seem to follow the obvious stepping-stone model of dispersal.
Location: Five land- based habitat archipelagos of limestone outcrops in the floodplain of the Kinabatangan River in Sabah, Malaysian Borneo.
Methods: We studied the phylogeography of three species complexes of endemic land snails, using multiple genetic markers. We calculated genetic distances between populations, applied beast2 to reconstruct phylogenies for each taxon and subsequently reconstructed ancestral ranges using ‘bioGeoBEARS’.
Results: We found spatial- genetic structure among nearby locations to be highly pronounced for each taxon. Genetic correlation was present at small spatial scales only and disappeared at distances of 5 km and above. Most archipelagos have been colonized from within the region multiple times over the past three million years, in 78% of the cases as a result of long-distance dispersal (LDD) or dispersal from non-adjacent limestone outcrops. The flow of the main geographical feature within the region, the Kinabatangan River, did not play a role.
Main conclusions: Phylogeographic structure in these Bornean land snails has only partly been determined by small-scale dispersal, where it leads to isolation- by- distance, but mostly by LDD. Our results demonstrate that island endemic taxa only very locally follow a simple stepping-stone model, whilst dispersal to non-adjacent islands and especially LDD, is most important. This leads to the formation of highly localized, isolated “endemic populations” forming the onset of a complex radiation of endemic species.“.

Their results may be a helpful context when researching the malacofauna of Neotropical archipelagos like Juan Fernández, Galápagos, Cocos Islands, and even in the Caribbean.

Reference:
Hendriks, K.P. et al., 2019. Phylogeography of Bornean land snails suggests long-distance dispersal as a cause of endemism. – Journal of Biogeography, 46 (5):932-944. DOI: 10.1111/jbi.13546

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”.

What does a Pacman eat?

Under this intriguing title a paper appeared that highlights the food of an Ecuadorian frog.

fig-1-full

“We describe for the first time the feeding ecology of the Pacific horned frog (Ceratophrys stolzmanni), as inferred through gastrointestinal tract content analysis and behavioural observations in its natural habitat. Ingested prey in adults ranged from mites and various insects to frogs and snakes. Prey items predominantly consisted of gastropods, non-formicid hymenopterans, and centipedes. We found no relationship between the size of the predator and the prey ingested, in terms of prey size, volume or number of items ingested. Additional direct observations indicate that all post-metamorphic stages are voracious, preying on vertebrates and engaging in anurophagy, cannibalism, and even necrophagy. Our study sheds light on the feeding habits of one of the least known species of horned frog”.

fig-2-full

Gastropods have not been specified in the paper, so we have to guess about which species it concerns and if they are really all belong to Pulmonata or also to other groups. The observations were made in the Arenillas nature reserve in El Oro province.

Reference:
Székely, D., Gaona, F.P., Székely, P., Cogălniceanu D., 2019. What does a Pacman eat? Macrophagy and necrophagy in a generalist predator (Ceratophrys stolzmanni). – PeerJ7e6406.

Achatina in Ecuador

Earlier this year a paper by Cuasapaz-Sarabia & Salas presented results about the occurrence of Achatina fulica in a private nature reserve. “Achatina fulica is an invasive terrestrial gastropod known as one of the 100 most harmful invasive species in the world. Achatina fulica is known in Ecuador since 2008, but the impact over their native ecosystems has not evaluated. The main objective was to determine the home range (HR) of this species in two zones with different levels of intervention in the Cerro Blanco reserve. The field work consisted in the capture, marking, recapture, taking of morphometric measurements and georeferencing of the individuals; for the analysis of data, HR was calculated using the convex polygon method, and environmental variables were correlated through a principal component analysis (PCA). The average HR in the altered zone was 3.58 m2 (± 0.93, n = 30), and on the ecotourist trail was 3.27 m2 (± 0.48, n = 40); the humidity was the environmental parameter that directly influences the life area and the population density in both zones study. The management of this invasive species does not appear as a key management issue for this private reserve, so it is recommended a control actions for its eradication“.

Schermafbeelding 2019-08-02 om 12.20.26

It is remarkable that – although the occurrence of this species in Ecuador is known for more than 10 years – eradication programs seem to be lagging behind. And even (private) nature reserves are not alarmed about it. Thus the risk of spread of this important pest species is still prevalent. A serious issue…

Reference:
Cuasapaz-Sarabia, J. & Salas, J.A., 2019. Área de vida de la especie invasora Achatina fulica (Gastropoda: Achatinidae) en un área de conservación de bosque seco ecuatoriano. Revista peruana de biología 26(1): 41 – 48.