Sunday 25 May 2014

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 hermaphrodites, and are eutelic; they have a fixed number of cells.

In a paper published in the journal ZooKeys on 12 April 2013, Rick Hochberg, Sarah Atherton and Vladimir Gross of the University of Massachusetts Lowell describe a new species of Gastrotrich from Capron Shoal off the Atlantic Coast of Florida.

The new species is placed in the genus Lepidodasys and given the specific name ligni, meaning ‘wood’, in honour of William ‘Woody’ Lee of the Smithsonian Marine Station at Fort Pierce, Florida, who assisted in the collection from which the specimens were described. Lepidodasys ligni is a strap-shaped Gastrotrich reaching up to 450 µm long. Its body was covered in eye-shaped scales arranged in a crossed-helical pattern across the dorsal and lateral surfaces and in a herringbone pattern on the dorsal line.

Schematic diagram of Lepidodasys ligni showing the crossed-helical scale pattern and a closeup of the musculature in the caudal region. Abbreviations: cg caudal gland; cm-pc circular musculature of the posterior constriction; co caudal organ; dh dorsal sensory hairs; eg mature egg; ep epidermal gland; fo frontal organ; in intestine; is interciliary scales; lc locomotory cilia; lh lateral sensory hairs; lm longitudinal muscle; pc posterior constriction; ph pharynx; TbA anterior adhesive tubes; TbD dorsal adhesive tubes; TbL lateral adhesive tubes; TbP posterior adhesive tubes; vllm ventrolateral longitudinal muscle. Hochberg et al. (2013).

Lepidodasys ligni was found living at a depth of 9.0 m on the Capron Shoal off the Atlantic Coast of Florida, where the sediment was fine-grained sand with a large proportion of coarser grains.

Light micrograph of Lepidodasys ligni in dorsal view. Hochberg et al. (2013).

The reproductive and muscular systems of Lepidodasys ligni. (A) Differential interference contrast photograph of the posterior end showing the accessory reproductive organs. (B, C) Confocal images (47 × 0.35 μm optical sections) of the musculature of the posterior end in lateral (B) and dorsal (C) views. (D) Closeup of the caudal organ with DIC microscopy E Lateral view of an entire specimen revealing the muscular system (73 × 0.4 μm optical sections). Abbreviations: cg caudal gland; cm-co circular muscles of the caudal organ; cm-pc circular muscles of the posterior constriction; co caudal organ; coc caudal organ canal; dlm dorsal longitudinal muscle; dllm dorsal lateral longitudinal muscle; fo frontal organ; hm helicoidal muscle (end position on midgut); lh lateral sensory hair; ph pharynx; TbP posterior adhesive tube; scm somatic circular muscles (thoughout trunk); vllm ventrolateral longitudinal muscle. Hochberg et al. (2013).

See also…

 A new species of Tardigrade from Latvia.

Tardigrades are small animals (adult sizes of 0.1-1.5 mm) distantly...

 A new species of Phoronid Worm from Tomioka Bay, Japan.

 A new species of Gastrotrich from KwaZulu-Natal.

Gastrotrichs are microscopic animals of uncertain...

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