Friday, 30 May 2014

A new species of Gastrotrich from the coast of São Paulo State, Brazil.

Gastrotrichs are microscopic animals of uncertain affinities, reaching at most 3 mm in size, though most species are far smaller. Less than eight hundred species have been described, living between sediment particles on the ocean floor, at the bottom of ponds and rivers and in biofilms covering grains of soil. They have flattened bodies covered in cilia, with a through gut but no respiratory or circulatory system. All gastrotrichs are hermaphrodites, and are eutelic; they have a fixed number of cells.

In a paper published in the journal ZooKeys on 12 April 2014, Antonio Todaro of the Department of Life Sciences at the University of Modena and Reggio Emilia, describes a new species of Gastrotrich from the sublitoral zone on the coast of São Paulo State, Brazil.

The new species is placed in the genus Ptychostomella, and given the specific name lamelliphora, meaning ‘thin-plate bearer’, a reference to the thin, plate-like scales on the animal’s sides. Ptychostomella lamelliphora is a 204-250 µm Gastrotrich with almost parallel sides. It lacks eye spots, but has paired, knob-like sensory organs on its head and sensory hair forming lateral columns along the body.

Ptychostomella lamelliphora, schematic drawings. (A) Dorsal view, showing the internal anatomy; (B) ventral view. Abbreviations: CO, caudal organ; CP, caudal pedicle; CTbV, cluster of ventral adhesive tubes; E, egg; EG, epidermal gland; FL, fleshy lobe; FO, frontal organ; I, intestine; KSO, Knob-like sensory organ; LS, lamellate scales; PhIJ, pharyngeo-intestinal junction; Pp, pharyngeal pores; T, testicle; TbA, anterior adhesive tubes; TbL, lateral adhesive tubes; TbV, ventral adhesive tubes. Todaro (2013).

Ptychostomella lamelliphora was found living at two locations, both in course sand sediments within the southern São Sebastião Channel off the coast of São Paulo State in Brazil. It was abundant at Praia Grande of Ihlabela at a depth of 3.0 m, but less numerous at Beluga.

Ptychostomella lamelliphora; (top) DIC photomicrograph and (bottom) SEM photomicrograph. Todaro (2013).

Ptychostomella lamelliphora, SEM photomicrographs in ventral view. (A) Close-up of the anterior region showing, among others, the plate-like-scales (arrow). (B) Trunk region showing the locomotory ciliation and most of the tubular adhesive apparatus. (C) Close-up of the ventrolateral region of the trunk, showing the cuticle punctuated by shallow pits. (D) Close-up of the posterior region showing the two clusters of ventral adhesive tubes, the ano-genital opening (arrowhead) and the column of plate-like-scales. Todaro (2013).

See also… 

 A new species of Gastrotrich from the Atlantic coast of Florida.


Gastrotrichs are microscopic animals of uncertain affinities, reaching at most 3 mm in size, though most species are far smaller. Less than eight hundred species have been described, living between sediment particles on the ocean floor, at the bottom of ponds and rivers and in biofilms covering grains of soil. They have flattened bodies covered in cilia, with a through gut but no respiratory or circulatory system. All...




Gastrotrichs are microscopic animals of uncertain affinities, reaching at most 3 mm in size, though most species are far smaller. Less than eight hundred species have been described, living between sediment particles on the ocean floor, at the bottom of ponds and rivers and in biofilms covering grains of soil. They have flattened bodies covered in cilia, with a through gut but no respiratory or circulatory system. All gastrotrichs...


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