Wednesday 13 September 2017

Nipponnemertes incainca: A new species of Ribbon Worm from the Caribbean Coast of Colombia.

Ribbon Worms (Nemertea) are a small group of worms related to Platyhelminth Flatworms. They have a simple anatomy, essentially a long, ribbon-like body with a dermal layer (skin), a through gut and a three layers of muscle. They have an extendable proboscis or stylet, which forms a cavity when retracted, and which is turned inside out when extended. This is used to subdue prey, often by penetrating their bodies, and in some species produces toxic secretions. Most Ribbon Worms are small, under 20 cm and often only a few mm, but there have been reports of Ribbon Worms over 50 m long, which if true would make them the longest known animals.

In a paper published in the journal ZooKeys on 22 August 2017, Jaime Gonzalez-Cueto, Lyda Castro and Sigmer Quiroga of the Facultad de Ciencias Básicas at the Universidad del Magdalena, describe a new species of Ribbon Worm from Inca Inca Beach at Santa Marta, in Magdalena Department, Colombia.

The new species is placed in the genus Nipponnemertes, which currently contains eighteen species from around the world, and is given the specific name incainca, in reference to the beah where it was found. The species was found living under rocks in the intertidal zone, with adults measuring between 11.7 and 22.5 mm in length and 1-2 mm wide. These are dark red on their dorsal surface and lighter below, and have a shield-shaped head with two irregular groups of eyespots, which can be retracted into the head when disturbed. The worms were capable of swimming, using strong undulating movements.

 Nipponnemertes incainca. (A) Dorsal view of entire worm. (B) Ventral view of entire worm. Abbreviation: p proboscis. Gonzalez-Cueto et al. (2017).

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