Clathrina andreusi, Sim-Smith & Hickman & Kelly, 2021

Sim-Smith, Carina, Hickman, Cleveland & Kelly, Michelle, 2021, New shallow-water sponges (Porifera) from the Galápagos Islands, Zootaxa 5012 (1), pp. 1-71 : 56-60

Clathrina andreusi sp. nov.

( Fig. 28 , Table 11)

Material examined. Holotype — MCCDRS9406, Nameless Island , 0.67° S, 90.586° W, 21 m, 9 Aug 2003 . Paratype — MCCDRS9407, Punta Vicente Roca , Isabela Island, 0.049° S, 91.558° W, 5–12 m, 19 June 2001 .

Type locality. Nameless Island .

Habitat and distribution. Nameless Island and Punta Vicente Roca, Isabela Island. Found growing on a vertical rock wall; 5–21 m. A common sponge that was observed at Floreana, Isabela, Pinzón , Santiago, San Cristóbel and Nameless Islands .

Description. Cormus is hemispherical to multilobate, 16 mm thick, and composed of tightly anastomosing tubes. Water collection tubes are scattered over the surface of the sponge forming delicate, membranous conules in the living specimen, these collapse in the preserved specimen. Single oscules are sometimes present at the apex of the conules. Colour in life is white, and in ethanol, light beige ( Fig. 28A–B ). Texture is firm but compressible.

Skeleton. The skeleton has no special organisation. Tube walls are 150–200 µm thick and are composed of two size categories of triactines ( Fig. 28D ).

Spicules. Megascleres— Triactines I, equiangular and equiradiate. Actines are conical with pointed tips; rays 125 (101–151) µm (n = 20) ( Fig. 28E ). Triactines II, same as triactines I but smaller; rays 58 (22–99) µm (n= 20) ( Fig. 28F ). There is an overlap in the size range of the two size categories, but a histogram of the spicules sizes shows that the spicules are divided into two categories ( Fig. 28C ; Table 11).

Etymology. Named for co-author Cleveland Hickman’s deceased son Andrew, a biologist who accompanied him on numerous research trips to the Galápagos Archipelago.

Remarks. Clathrina is a large genus and there are 18 described species from the eastern Pacific, though none from the Galápago Islands. Six of these species are white in life: C. peruana Azevedo, Cóndor-Luján, Willenz, Hajdu, Hooker & Klautau, 2015 , C. cylindractina Klautau, Solé-Cava & Borojevic, 1994 , C. delicata Fontana, Cóndor-Luján, Azevedo, Pérez & Klautau, 2018 , C. fakaravea Klautau, Lopes, Guarabyra, Folcher, Ekins & Debitus, 2020 , C. fjordica Azevedo, Hajdu, Willenz & Klautau, 2009 and C. nuroensis Azevedo, Cóndor-Luján, Willenz, Hajdu, Hooker & Klautau, 2015 . Clathrina andreusi sp. nov. can be differentiated from these species as follows:

• C. cylindractina , C. fjordica and C. peruana only possess one size category of triactines;

• C. delicata and C. nuroensis possess three size categories of triactines;

• C. fakaravea from French Polynesia possesses two size categories of triactines, but they are of a different size range (96 (43–135) µm and 160 (138–181) µm) to C. andreusi sp. nov.

In addition, the total size range of spicules from these six species do not match the total size range for C. andreusi sp. nov.

Subclass Calcaronea Bidder

Order Leucosolenida

Figures

FIGURE 28. Clathrina andreusi sp. nov. holotype, MCCDRS9406: A. In situ. B. Holotype, preserved. C. Histogram of the size of the actines showing the separation into two size classes. D. Cross section showing the tube walls. E. Actine I. F. Actine II.