Tuesday 4 June 2013

Three new species of Palm Weevil from Columbia.

Palm Weevils of the genus Anchylorhynchus are found from Panama to Argentina. They have a symbiotic relationship with Palms of the genera ButiaCocosOenocarpus and Syagrus, with the adults acting as pollinators and the larvae growing within non-developing fruit (these do not appear to be inherently different from the developing fruit, they are modified by the actions of the Weevils). The apparent damage that the Weevils do to some Palm fruit crops has led to attempts to control them, though this interrupts the Palm's reproductive cycle, halting production of fruit completely.

In a paper published in the journal Zootaxa on 4 April 2013, Bruno de Medeiros of the Museum of Comparative Zoology at the Department of Organismic and Evolutionary Biology at Harvard University, and Luis Núñez-Alvellaneda of the Grupo de Investigación de Palmas Silvestres Neotropicales at Universidad Nacional de Colombia, describe three new species of Palm Weevil from Palms of the genus Syagrus growing in the lowland rainforests of Columbia.

The first new species is named Anchylorhynchus pinocchio, in reference to the elongated rostrum (snout) of the males of the species. Anchylorhynchus pinocchio shows distinct sexual dimorphism (i.e. the males and females are different), which is unusual in Weevils. This species lives on the Palm Syagrus sancona in lowland rainforest and gallery forests of Cesanare Department, Columbia, at altitudes of between 150 and 500 m.

Anchylorhynchus pinocchio, (A) male and (B) female. Scale bars are 1 mm. De Medeiros & Núñez-Alvellaneda (2013).

The second new species is named Anchylorhynchus centrosquamatus, meaning 'central scales', in reference to the scales of the pronotum (front part of the thorax), which are directed towards the centre. The species was found living on the Palm Syagrus orinocensis in lowland rain forest or gallery forest at elevations ranging from 150 to 500 m.

Anchylorhynchus centrosquamatus. Scale bar is 1 mm. De Medeiros & Núñez-Alvellaneda (2013).

Anchylorhynchus centrosquamatus among flowers of Syagrus orinocensis in Vereda la Tigrana, Monterrey, Colombia. De Medeiros & Núñez-Alvellaneda (2013).

The final new species is named Anchylorhynchus luteobrunneus, meaning 'yellow and brown'; the species is variable in colouration, coming in yellow, brown and a mixture of the two. The species was found living on the Palm Syagrus sancona,  in lowland rainforests, gallery forest and piedmont forests in Casanare, Meta and Guaviare departments of Columbia, at elevations ranging from 100 to 1000 m.

Anchylorhynchus luteobrunneus, three different colour morphs. Scale bars are 1 mm. De Medeiros & Núñez-Alvellaneda (2013).

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