''Borojevia aspina'' is a
species
A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...
of
calcareous sponge
The calcareous sponges or calcereans are sponges that make up the class Calcarea, characterized by spicules made of calcium carbonate in the form of high-magnesium calcite or aragonite. While the spicules in most species are triradiate (with three ...
from Brazil. The species name refers to the lack of spines in the apical actine.
Description
Massive cormus formed of thin, regular and tightly anastomosed tubes similar to those of ''
Borojevia brasiliensis'' and ''
Borojevia cerebrum
''Borojevia'' is a genus of calcareous sponge in the family Clathrinidae. The genus is named after sponge researcher Radovan Borojevic.
Description
Calcinea in which the cormus comprises tightly anastomosed tubes. The skeleton contains regular ( ...
''. Oscula are simple apertures surrounded by a thin membrane. They are located on top of conical projections distributed throughout the cormus and receive the excurrent water from water-collecting tubes. In preserved specimens, it is difficult to recognise the oscula.
The skeleton has no special organisation, and it comprises triactines, tetractines and tripods. Triactines and tetractines are equiangular and equiradiate; their actines are slightly conical, with blunt tips. Triactines are the most abundant spicules; the apical actine is shorter and thinner than the facial ones. It is also straight, conical, and unlike that of ''B. brasiliensis'' and ''B. 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 they are only similar to large conical triactines. They are distributed on a monolayer on the external tubes, delimiting the cormus. ''B. aspina'' has a sciaphile habitat.
References
World Register of Marine Species entry
aspina
Sponges of Brazil
Endemic fauna of Brazil
Sponges described in 1994
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