Sciency Thoughts: Magdelena Department

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).

Parachemmis julioblancoi: A new species of Corinnine Spider from the Sierra Nevada de Santa Marta of Colombia.

Corinnine Spiders of the genus Parachemmis are distinguished from related genera by the presence of spines on their first pair of legs. To date three species have been described, one from Brazil, one from Guyana and one from Panama, however since this range covers one of the most biodiverse regions on the planet, it is thought highly likely that there are many more undiscovered species in this genus.

In a paper published in the journal ZooKeys on 8 June 2017, Leonel Martinez, Eduardo Villarreal and Neis Martinez of the Grupo de Investigación ECOSIN and Grupo de Investigación Biodiversidad del Caribe colombiano at the Universidad del Atlántico, describe a new species of Parachemmis from San Pedro de la Sierra in the Sierra Nevada de Santa Marta of Magdalena Department in Colombia.

The new species is named Parachemmis julioblancoi, in honour of Julio Enrique Blanco, the founder of the Universidad del Atlántico, for his many contributions to art and education in Colombia. The species is described from four male and six female specimens, collected from leaf litter in a wet mountain forest at an altitude of 2104 m. The females are larger than the males, with one specimen measured at 11.0 mm, compared to 7.7 mm for a male. Both are grey and yellow in colour.