Tylosigma Topsent, 1894,

Van, Rob W. M., 2017, Sponges of the Guyana Shelf, Zootaxa 1, pp. 1-225: 128

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http://doi.org/ 10.5281/zenodo.272951

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Tylosigma Topsent, 1894


Genus Tylosigma Topsent, 1894 

Remark. The genus Tylosigma  was synonymized with Hymedesmia  ( Hymedesmia  ) in the Systema Porifera (chapter Hymedesmiidae  by Van Soest 2002b), but it is here proposed to be revived as a valid genus. The discovery of a second species with similar characters as the type species H. campechiana Topsent, 1889  , and the considerable difference with Hymedesmia  s.s. (no tornotes, no echinating acanthostyles) support the valid status. The definition of the genus Tylosigma  needs emendation from Topsent’s original definition: Desmacellidae  (?) with single tylostyles erect on the substratum, pointed ends outwardly directed, and with sigmas as microscleres.

Type species Hymedesmia campechiana Topsent, 1889  .