Tag Archives: ecuador

Galápagos land snails

Just published as advance access: a paper by Phillips et al. on colonisation and speciation in the Galápagos archipelago, based on an extensive study of DNA.

The abstract reads as follows: “Newly arrived species on young or remote islands are likely to encounter less predation and competition than source populations on continental landmasses.The associated ecological release might facilitate divergence and speciation as colonizing lineages fill previously unoccupied niche space. Characterizing the sequence and timing of colonization on islands represents the first step in determining the relative contributions of geographical isolation and ecological factors in lineage diversification. Herein, we use genome-scale data to estimate timing of colonization in Naesiotus snails to the Galápagos islands from mainland South America. We test inter-island patterns of colonization and within-island radiations to understand their contribution to community assembly. Partly contradicting previously published topologies, phylogenetic reconstructions suggest that most Naesiotus species form island-specific clades, with within-island speciation dominating cladogenesis. Galápagos Naesiotus also adhere to the island progression rule, with colonization proceeding from old to young islands and within-island diversification occurring earlier on older islands. Our work provides a framework for evaluating the contribution of colonization and in situ speciation to the diversity of other Galápagos lineages“.

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This is a very interesting study that focusses entirely on the island fauna and the within-archipelago speciation. The colonisation from the mainland and the relationship between the the mainland and off shore species of Naesiotus remains open for future work.

Reference:
Phillips, J.G. et al., 2019. Archipelago-Wide Patterns of Colonization and Speciation Among an Endemic Radiation of Galápagos Land Snails. Journal of Heredity: 1-11 (advance access) doi:10.1093/jhered/esz068

Where is the Miller collection?

Just published: a paper on Konrad Miller, giving a short biography and a list of described taxa. Most of his fossil material has been located, but for me the big question is: where is the Miller collection with Recent material from Ecuador?

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The above label shows his handwriting, and can thus be a guidance for searches in museums. Likely in Germany, but I also probed the Salzburg collection (in vain!) as he bequeathed in later life his legacy to Salzburg University.

Any suggestions about his Ecuadorian material would be very helpful.

Reference:
Breure, A.S.H. A little-known German naturalist: Konrad Miller (1844-1933) and his malacological contributions.  Archiv für Molluskenkunde, 148 (2): 129-136.

New Granada

Working on a paper related to Colombian Drymaeus reveals some well-known puzzles about old localities who have not been traced again. In fact, the denomination of the area as “New Grenada” is somewhat of a puzzle, as the meaning of that terminology has shifted over time.
Just out of curiosity, I searched for pictures on “New Grenada” in Google. I found a few, and the shift in what has to be called “New Grenada” is clearly illustrated in the following time-series.

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Map of New Grenada
Author: John Pilkerton, 1811. Scale 1:3,400,000. Publshers: Cadell & Davies; Longman, Hurst, Rees, Ome & Brown, London

 

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Map of the Kingdom of New Grenada
Author: Hall Sidney, 1827. Scale 1:5,700,000. Publisher: Caddell, London.

 

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Map of Venezuela, New Grenada & Equador
Author: Henny Tanner, 1836. Scale 1:6,969,600. Publisher: H.S. Tanner, Philadelphia

The first map shows that New Grenada at one time reached the borders of the Río Marañon, now in the territory of Perú. The last map is especially interesting, since it depicts the situation at the time from which many type material originate, that can still be found in museum collections. What struck me is the very different limitation of the ‘Provinces” or “Departments”. Colombia consisted in the mid-19th century of four parts: Cauca, Cundinamarca, Magdalena and Boyacá. Their geographical limits are, however, rather different from their current, being far more extensive. When interpreting old locality labels this knowledge can be very helpful to pinpoint certain places, which might not be located where one would expect them with today’s map in front.

Just an example of some puzzles that I consider solved, where some geographical knowledge and modern facilities go hand in hand. One of the collectors who travelled extensively through Colombia at that time was Thomas Bland (1809-1885). Many of his collected material was studied by Pilsbry during his work for the Manual of Conchology. But quite often modern authors may be puzzled about some of the places that were visited by Bland.
There were three Drymaeus species with localities originating from Bland that, at first, I was unable to locate. “Between Salamina and Cabuyal, west of Ervé” was one of them, a locality reported for D. bogotensis (Pfeiffer). I looked up Ervé in the GNS gazetteer but nothing turned up. On the other hand, Salamina and Cabuyal – though not sounding like common names – turned up many times from different parts of Colombia. I decided to leave it and went on with my revision.
Another puzzling locality was “near Santa Ana”, type locality of D. decoratus goniobasis Pilsbry, based on material collected by Bland. When I looked up “Santa Ana” in the gazetteer, many places of that name turned up from all over the country.
Finally, I came to D. geometricus (Pfeiffer), for which Pilsbry had another locality from Bland: “Forests in the mountains below Ervé, on the road to Santa Ana”. I’m unaware if there has anything been published about the journeys of Bland in Colombia, but now I had three parts of a puzzle and I decided to find some solution. First the place “Ervé”. This is a highly unusual spelling in Spanish, so it could be phonetical. I decided to look for “erve” in the GNS database, but not with “starts with” option enabled, but with the “contains” option instead. It turned up 6 names, of which 3 could be skipped right away. I ended up with “Páramo de Herveo” and two variants of the populated place “Herveo”, all at or very close to 05° 05′ 00″ N 075° 10′ 00″ W, which is in Dept. Tolima. The first puzzle bit was in place.
The next step was to find Santa Ana, which could not be far away. When I scrutinized the list of names I did not find a place with a modern name that seemed logical to me. Then I was struck by the name Falán in the list, with a variant name Santa Ana, and located 25 km ENE of Herveo. That seemed logical to me, both places are in the region of Fresno in the upper Magdalena valley, from which the species have been reported.
Then finally Salamina and Cabuyal. With the location of Herveo in mind I looked through all the records for these names in the GNS gazetteer. Salamina is in Dept. Caldas, nearly 50 km NW of Herveo. And there is a “Quebrada Cabuyal” in Tolima, 60 km SE of Herveo. Both places are marked with red in the map below, while the three localties of the Drymaeus species mentioned are marked with yellow. Three species finally found their home.

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This post was originally published in my previous blog in November 2007; thanks to the WaybackMachine I’m able to re-publish it here.

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.

What does a Pacman eat?

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

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“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”.

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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“.

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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.

Galápagos Gastrocopta

A recent paper by Miquel & Brito focusses on Gastrocopta species from the Galápagos, already mentioned in a previous paper.
Their abstract is as follows “A revision of Gastrocopta from the Galápagos Islands (Ecuador) is made. Four new species from Pinzón, Santa Cruz and Floreana Islands are described; species previously known are redescribed and new locations are added. Gastrocopta (Gastrocopta) reibischi is revalidated through new records from Floreana, Isabela and San Bartolomé Islands. Shell shape and the number, morphology and disposition of the apertural barriers support the discrimination of the taxa. The species have cylindrical to pupoid shells; the number of apertural barriers –differentiated as lamellae, folds and nodulae – varies between 4 and 11, almost completely occluding the aperture in the more complex cases. These structures are: angular-parietal, infraparietal, supracolumellar, columellar, subcolumellar lamellae, and supernumerary, basal, infrapalatal, lower-palatal, interpalatal, upper-palatal and suprapalatal folds. In addition to this classic scheme, a supernumerary fold and a nodule are added. Calcareous concretions –pustulae – are found in several species, mainly located in the peristome. The aulacognathous jaw and radular dentition formulae of Gastrocopta (Gastrocopta) clausa and Gastrocopta (Gastrocopta) munita, are described and photographed for the first time“.

The new species are all belonging to the nominate subgenus, and have been named respectively G. (G.) aliciae, G. (G.) christinae, G. (G.) franki, and G. (G.) herrerai. This means that the number of Gastrocoptid species from this archipelago has doubled! As most research on this group so far has been limited to a few islands, further novelties are to be expected as a result of future work.

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Reference:
Miquel, S.E. & Brito, F.F., 2019. Taxonomy and distribution of species of Gastrocopta Wollaston 1878 (Mollusca: Gastropoda: Gastrocoptidae) from the Galápagos Islands (Ecuador). – Molluscan Research, 39: 265-279.