Revision of the genus Clathrina (Porifera, Calcarea) Author Klautau, Michelle Author Valentine, Clare text Zoological Journal of the Linnean Society 2003 2003-09-30 139 1 1 62 https://academic.oup.com/zoolinnean/article-lookup/doi/10.1046/j.0024-4082.2003.00063.x journal article 10.1046/j.0024-4082.2003.00063.x 0024-4082 5432634 CLATHRINA ASPINA KLAUTAU, SOLÉ- CAVA & BOROJEVIC, 1994 Type locality: Arraial do Cabo (Gruta Azul), Rio de Janeiro , Brazil . Type: BMNH 1999.9 .16.3 ( holotype /alcohol). Arraial do Cabo (Gruta Azul), Rio de Janeiro , Brazil . Collected by G. Muricy ( 13 June 1987 ) , MNRJ 4053 ( paratype /alcohol). Arraial do Cabo (Gruta Azul), Rio de Janeiro , Brazil . Collected by N. Boury-Esnault ( 13 June 1987 ) . Citations: Klautau & Borojevic (2001) . Colour: White in life and when preserved. Description: Massive cormus formed of thin, regular and tightly anastomosed tubes ( Fig. 3A ) similar to those of C. brasiliensis and C. cerebrum . Oscula are simple apertures surrounded by a thin membrane. They are located on the top of conical projections distributed throughout the cormus and receive the excurrent water from water-collecting tubes. In preserved specimens, it is difficult to recognize the oscula. The skeleton has no special organization, and it comprises triactines, tetractines and tripods ( Fig. 3B ). Triactines and tetractines are equiangular and equiradiate; their actines are slightly conical, with blunt tips. Triactines are the most abundant spicules; the apical actine ( Fig. 3C ) is shorter and thinner than the facial ones. It is also straight, conical, sharp and, unlike that of C. brasiliensis and C. cerebrum , smooth. Occasionally, it is possible to find apical actines with vestigial spines. Tripods are typical, with a raised centre and conical actines but sometimes are only similar to large conical triactines. They are distributed in a monolayer on the external tubes, delimiting the cormus. C. aspina has a sciaphile habitat.

Length (Mm)		Width (Mm)
min	mean	s	max	mean	s	n
Triactines	55.0	70.0	± 7.5	80.0	6.0	± 1.0	30
Tetractines	52.5	68.8	± 7.8	82.5	6.0	± 1.0	30
Apical actine	40.0	50.3	± 6.3	62.5	5.0	0	30
Tripods	62.5	78.8	± 8.8	92.5	9.5	± 0.8	30

Remarks: Although there are morphological similarities to C. brasiliensis and C. cerebrum , C. aspina is easily distinguished from those species by the absence of spines on the apical actine of the tetractines. Allozyme variation studies of the populations of C. aspina and C. brasiliensis from Arraial do Cabo have been undertaken ( Klautau et al ., 1994 ) and results show that, although living in sympatry, there is no gene flow between them.