Weevils, Curculionidae, are one of the largest and most diverse groups of Beetles. They first appeared in the Early Cretaceous, becoming common and diverse by the end of that period. Broad-nosed Weevils, Entiminae, first appear in Early Eocene Fushan Amber from China. They have larvae which infest the roots of plants, a novel innovation on this group, which has allowed them to exploit a range of new environments, enabling them to diversify rapidly and spread widely during the Eocene.
In a paper published in the journal Paleontologica Electronica in May 2017, George Poinar of the Department of Integrative Biology at Oregon State University and Andrei Legalov of the Institute of Systematics and Ecology of Animals of the Siberian Branch of the Russian Academy of Sciences describe five new species of Entimine Weevil from amber mines in the northern part of the Dominican Republic.
Amber from the Dominican Republic is generally thought to be 15-20 million years old (i.e. Miocene in age), and is obtained from mines in the Cordillera Septentrional mountain range, where it is found as inclusions in turbiditic sandstones (marine landslip deposits). This secondary deposition makes it possible that the Amber is much older than the deposits in which it is found, possibly as old as 40 million years (Early Eocene). It was produced by a Leguminous tree, Hymenaea protera, which, based upon the ecology of the organisms found in the amber, is interpreted as having lived in moist tropical forests.
Amber from the Dominican Republic is generally thought to be 15-20 million years old (i.e. Miocene in age), and is obtained from mines in the Cordillera Septentrional mountain range, where it is found as inclusions in turbiditic sandstones (marine landslip deposits). This secondary deposition makes it possible that the Amber is much older than the deposits in which it is found, possibly as old as 40 million years (Early Eocene). It was produced by a Leguminous tree, Hymenaea protera, which, based upon the ecology of the organisms found in the amber, is interpreted as having lived in moist tropical forests.
The first new species described is placed in the genus Diaprepes, which is still found in the Caribbean today, and given the specific name squamula, meaning scaly, in reference to the dense scaly covering of the Weevil. The species is described from a single specimen, 9.0 mm in length with a 0.6 mm snout, black in colour, with a dense covering of light, rounded scales.
Ventral view of Diaprepes squamula, In Dominican amber. Scale bar is 1.0 mm. Poinar & Legalov (2017).
The second species described is placed in the genus Lachnopus, also still found in the Caribbean today, and given the specific name serraticrus, meaning ‘toothed-leg’, in reference to a pattern of prominent serrations on the Insect’s tibia. This species is also described from a single specimen, 7.4 mm in length with a 1.4 mm snout, black in colour with small, subcircular scales.
Lateral view of Lachnopus serraticrus in Dominican amber. Scale bar is 1.3 mm. Poinar & Legalov (2017).
The fourth new species is also placed in the genus Apodrosus, and given the specific name canalinasus, meaning ‘grooved-nose’ in reference to a distinctive furrow on the snout. The species is described from a single specimen, 4.5 mm in length, with a 0.8 mm snout, and covered in small oval scales.
The third new species described is placed in the genus Apodrosus, another modern Caribbean genus, and given the specific name tinctocorpus, meaning ‘dyed body’ in reference to the colour of the body, which brown-black and lacks any markings. The species is described from a single specimen, 5.0 mm in length with a 0.8 mm snout, and small oval scales.
Lateral view of Apodrosus tinctocorpus in Dominican amber. Scale bar is 1.2 mm. Poinar & Legalov (2017).
The fourth new species is also placed in the genus Apodrosus, and given the specific name canalinasus, meaning ‘grooved-nose’ in reference to a distinctive furrow on the snout. The species is described from a single specimen, 4.5 mm in length, with a 0.8 mm snout, and covered in small oval scales.
Lateral view of Apodrosus canalinasus in Dominican amber. Scale bar is 0.8 mm. Poinar & Legalov (2017).
The fifth new species described is placed in the genus Promecops, today found in the Caribbean, as well as in Central and South America, and given the specific name divarichela, meaning ‘spread-apart claws’, in reference to the free tarsal claws. The species is described from a single specimen 3.1 mm in length with a 0.4 mm snout, brown-black on colour and with curved, narrow scales.
Lateral view of Promecops divarichela in Dominican amber. Scale bar is 0.7 mm. Poinar & Legalov (2017).
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