Clathrina smaragda, Lopes & Padua & Cóndor-Luján & Klautau, 2018

Lopes, Matheus V., Padua, André, Cóndor-Luján, Báslavi & Klautau, Michelle, 2018, Calcareous sponges (Porifera, Calcarea) from Florida: new species, new records and biogeographical affinities, Zootaxa 4526 (2), pp. 127-150 : 132-134

Clathrina smaragda sp. nov.

( Fig 3 ; Table 3)

Diagnosis. Clathrina with green cormus formed by loosely and irregularly anastomosed tubes and two categories of triactines: regular and parasagittal.

Material examined. Holotype: UFRJPOR 8359, Looe Key , Florida, United States of America (24°32’51 N, 81°24’24 W), 10–15 m of depth, coll. A. Padua & M. C. Díaz, 12 August 2015. ETYMOLOGY. From the Latin smaragdus (= emerald) for its dark green colour.

Colour. Dark green when alive ( Fig 3A ) and light green after fixation ( Fig 3B ).

Morphology. Cormus encrusting, formed by loose and irregularly anastomosed tubes. The tubes are large (reaching 0.7 mm of diameter), bright and rigid probably due to the presence of thicker spicules in the external surface. There are no water-collecting tubes ( Figs 3A, B ). The single specimen collected is small and measured 4.5 x 5.0 x 1.0 mm. The aquiferous system is asconoid. No granular cells were observed. The skeleton has no special organisation. It is composed mainly of parasagittal triactines, and few regular (tripod-like) triactines located on the surface of the tubes ( Figs 3 C–F). These tripod-like spicules are probably responsible for the rigid consistency of the tubes.

Spicules ( Figs 3D, E , Table 3).

Triactines I ( Fig 3D ): Parasagittal (equiangular, but with the unpaired actine longer than the paired ones). Actines are cylindrical to slightly conical with blunt to sharp tips.

Triactines II ( Fig 3E ): Regular (equiangular and equiradiate). Actines are conical with blunt to sharp tips.

Ecology. The single specimen was found between 10 to 15 m of depth. It was attached to a coral fragment, protected from the sunlight. No associated organisms were found.

Distribution. Provisionally endemic to Looe Key, Florida, United States of America.

Remarks. This is the first species of the genus Clathrina to be green. It is also one of the six known species of Clathrina without a peduncle but with parasagittal spicules composing the skeleton: C. broendstedi Rapp et al., 2011 , C. curacaoensis Cóndor-Luján et al., 2018 , C. rotundata Voigt et al., 2017 , C. rowi Voigt et al., 2017 , and C. sororcula Van Soest & De Voogd, 2015 . Besides the green colour, C. smaragda sp. nov. can be distinguished from all those other species of Clathrina based on the proportion of parasagittal spicules. In C. smaragda sp. nov., parasagittal spicules (triactines I) are more frequent than the regular ones (triactines II), while in the other species, they occur mainly as a variation of the regular triactines, being rare or less frequent.

In our molecular results, C. smaragda sp. nov. formed a clade together with C. curacaoensis with 91% bootstrap and a p-distance of 1.3%. They can be morphologically differentiated from each other by the frequency and location of the parasagittal spicules. In C. smaragda sp. nov., parasagittal spicules are the most abundant spicules and are present in the entire cormus, while in C. curacaoensis they are not abundant and are present only in the tubes that attach the sponge to the substrate. Moreover, the regular triactines differ in size: in C. curacaoensis , they range from 87.5 to 130.0 µm, while in C. smaragda sp. nov. they are smaller (67.5 to 86.4 µm).

Figures

FIGURE 3. Clathrina smaragda sp. nov. (UFRJPOR 8359 - Holotype). A. Specimen in situ. B. Specimen in ethanol. C. Tangential section. D. Detail of triactine I (parasagittal). E. Detail of triactine II (regular) F. Triactines on the surface of the tube (SEM).