Tuesday 25 June 2013

Two new species of Amphipod Crustacean from the Gulf of Thailand.

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. Amphipods are extremely widespread and numerous, but often overlooked due to their small size, most species being under 10 mm, though giant species exceeding 30 cm are known from the deep oceans.

In a paper published in the journal ZooKeys on 5 June 2013, Koraon Wongkamhaeng of the Excellence Center for Biodiversity of Peninsular Thailand at the Prince of Songkla UniversityCharles Coleman of the Museum für Naturkunde Berlin and Pornsilp Pholpunthin, also of the Excellence Center for Biodiversity, describe two new species of Amphipod Crustaceans from the Seagrass beds of Talet Bay and Phangan Island in the Lower Gulf of Thailand.

The first new species described is placed in the genus Maeropsis, and given the specific name paphavasitae, in honour of Nittharatana Paphavasit of Chulalongkorn University, who has studied biology of Seagrass beds in the Gulf of Thailand. Maeropsis paphavasitae is a 5 mm Amphipod Crustacean found living on the Seagrass Thalassia hemprichii in beds in Talet Bay.

Maeropsis paphavasitae, line drawing of male; the females are essentially similar. Wongkamhaeng et al. (2013).

The second new species is placed in the genus Rotomelita, and given the specific name longipropoda, in reference to the length of the propodus (second segment) of the male gnathopod (limb on the second thoracic segment). Rotomelita longipropoda is a 1.65 mm Amphipod Crustacean found living on the Seagrasses Thalassia hemprichii and Halophila ovalis, in beds off Phangan Island. The females are slightly larger than the males, and are distinct anatomically.

Rotomelita longipropoda; male (top) and female (bottom). Wongkamhaeng et al. (2013).

Map showing the sites where the specimens were found. Wongkamhaeng et al. (2013).

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