Friday 21 November 2014

A new species of Wormshrimp from the Maldives.

Wormshrimps are a poorly understood group of Amphipod Crustaceans found living in a variety of subterranean environments, including the interstitial spaces in sandy sediments from beaches to the deep ocean floors, to cave systems and fresh and brackish groundwater systems on continents. They are thought to be common in sandy environments on tropical reefs, but how they are dispersed is a mystery, as their larvae are not free-swimming and they produce low numbers of eggs (large numbers of eggs are thought to be a pre-requisite for trans-oceanic distribution, as most are expected to be lost without reaching a new home).

In a paper published in the journal ZooKeys on 22 October 2014, RonaldVonk of the Naturalis Biodiversity Center in Leiden and the Institute forBiodiversity and Ecosystem Dynamics at the University of Amsterdam, and DamiáJaume of the Instituto Mediterráneo de Estudios Avanzados, describe a new species of Wormshrimp from coral reef sand off Magoodhoo Island in the Maldives.

The new species is placed in the genus Ingolfiella and given the specific name maldivensis, in reference to the area where it was found. The species is described from six female specimens, one collected from Blue Cove and five from  Dharamboodhoo Reef, both close to Magoodhoo Island in the Maldive Archipelago, in the  central Indian Ocean. The Ingolfiella maldivensisspecimens range from 1.55 to 1.85 mm in length. It is an elongate, worm-like Crustacean, with lateral lobes on its head and javelin-shaped spines on its mouthparts.

Ingolfiella maldivensis, female 1.80 mm (including telescoped body somites). Arrows point to gills and oostegites on the third and fourth pereiopods, and on gills on the fifth pereiopod. Vonk & Jaume (2014).

Ingolfiella maldivensis closely resembles Ingolfiella quadridentata, a species known only from Curaçao in the Caribbean. Wormshrimps often resemble other species from distant locations living in similar environments far more than they resemble species living close by in different environments. Vonk and Jaume suggest that this is due to the group being particularly prone to parallel evolution (distantly related species developing similar features in response to similar environmental pressures, rather than some unknown distribution method.

See also…

Amphipods are (mostly) small, laterally compressed Crustaceans with differentiated legs (i.e. not all their legs are the same). Female Amphipods carry their eggs in brood pouches till they hatch; the young resemble the adults and typically reach maturity after about six molts. 

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