Saturday 2 August 2014

A new species of Pygmy Grasshopper from Miocene Dominican amber.

Pygmy Grasshoppers (Tetrigidae) are small Orthopteran Insects related to True Grasshoppers, Crickets and Katydids, found across much of the globe but most numerous and diverse in the tropics. The name ‘Pygmy Grasshoppes’ is somewhat misleading, as they seldom feed on Grass, instead mainly consuming Bryophytes (Mosses), Algae, Lichens and only the occasional small vascular plant; the group are also known as Grouse Locusts or Ground Hoppers. Surprisingly for Orthopterans, many species are capable swimmers, and live semi-aquatic lifestyles. They are a large group today, with over 1700 described species, however their fossil record is rather limited, with only eight previously described species, including two from Cretaceous volcano-sedimentary deposits in Russia, two from Eocene Baltic amber, one from the Eocene Green River Formation of the US, one from the Miocene of Oeningen in Switzerland and two previous species described from Miocene Dominican amber.

In a paper published in the journal ZooKeys on 30 July 2014, Sam Heads and Jarred Thomas of the Illinois Natural History Survey at the Prairie Research Institute of the University of Illinois at Urbana-Champaign and Yinan Wang of Arlington Virginia, describe a new species of Pygmy Grasshopper from Miocene Dominican amber.

The new species is named Electrotettix attenboroughi, where ‘Electrotettix’ means ‘Amber-grasshopper’ and ‘attenboroughi’ honours Sir David Attenborough, the distinguished British broadcaster and naturalist, for his role in inspiring a generation of natural scientists. The species is described from a single female specimen, 8 mm in length. 

Electrotettix attenboroughi in left lateral view, photograph (top) and explanatory drawing (bottom). Heads et al. (2014).

Electrotettix attenboroughi resembles many modern members of the Subfamily Cladonotinae from the Caribbean, and is placed within this group. However all modern members of the Cladontinae are wingless, while a small hind-wing is preserved in Electrotettix attenboroughi. While it is not thought likely that this wing could have been used for flying, it is significant to find a residual wing in an Insect which appears to be more related to modern Caribbean Cladonotinae than modern non-Caribbean species, as this suggests that wing-loss has occurred separately at least twice within the group. 

The preserved right hindwing of Electrotettix attenboroughi. Scale bar is 0.25 mm. Heads et al. (2014).

The Cladonotinae are the dominant group of Pygmy Grasshoppers in the Caribbean comprising around 70% of modern species and all known fossils, though they are only a minor part of the fauna in neighbouring parts of Central and South America. The group appear to have a complex evolutionary history in the islands that matches the complex geological history of the islands themselves, where plate movements have driven the rapid formation, migration, breakup and merging of islands, as well as the development of mountain ranges within the islands, leading to a complex network of different micro-environments, connecting and separating to one-another  on a timescale of only a few million years, while reaming separate from any major landmass, a prefect environment for the rapid evolution of new species in a group of small, flightless Insects.

See also…

The Rancho La Brea Tar Pits of Los Angeles County are renowned worldwide for their well preserved late-Pleistocene fossils, notably...

The Dominican Republic hosts three sites noted for the production of exceptionally clear amber with numerous preserved Insects, together regarded as a fossil Lagarstätte. The amber is thought to be the preserved resin of an extinct tropical tree, Hymenaea protera, a type...

The Protogryllidae are a family of early Crickets known mainly from the Jurassic of Eurasia, with some members known from the Late...

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