Polyaxone monaxonids: revision of raspailiid sponges with polyactine megascleres (Cyamon and Trikentrion) Author Soest, Rob van Author Carballo, Jose Luis Author Hooper, John text ZooKeys 2012 239 1 70 http://dx.doi.org/10.3897/zookeys.239.3734 journal article http://dx.doi.org/10.3897/zookeys.239.3734 1313-2970-239-1 Cyamon koltuni Sim & Bakus, 1986 Figs 10 A-F Cyamon koltuni Sim and Bakus 1986 : 18, fig. 3 (California); Lee et al. 2007 : 210. Material examined. HolotypeUSNM 33630, preserved in alcohol, California, Santa Catalina Island, Big Fisherman's Cove, 33.45°N , 118.4833°W , 6 m. LEB-ICML-UNAM 1497, preserved in alcohol, Mexican Pacific, Islas Marietas (Nayarit), Cueva Marietas, 20.7003°N , 105.5658°W , 11 m, coll. J.L. Carballo, 11 -10- 2006. The holotype (Fig. 10A1) was received on loan from the Smithsonian Institution, but in view of the small crust and previous studies of it, including SEM examination ( Sim and Bakus 1986 : Fig. 3; Lee et al. 2007 ), and the presence of additional material, it was decided that no further sampling of it was necessary. We report the occurrence of a second specimen of this species from Mexican Pacific waters, from which we obtained our data for the description below. Description. Thinly encrusting (Fig. 10A1, A2) on rocks, color bright orange. Size of Mexican specimen 12 x 15 cm, thickness 1 mm. Surface very hispid. Skeleton: a basal mass of polyactine spicules (Fig. 10B), upon which with styles are erected (Fig. 10C), no discernible skeletal organization due to thinness. Spicules: long thin styles, short thin styles, short thick styles, polyactines. Long thin styles (Fig. 10D, 10D1): rather straight, with faint subterminal tyle at the rounded end, 900 -967- 1400 x 5 -5.9- 7 µm . Short thin styles (Fig. 10E), occasionally oxea-like with tapering thin endings, 265-370 x 2.5-5 µm . Short thick styles (Fig. 10F): slightly curved and thickest subterminally near the faintly constricted rounded end, 150 -316- 425 x 10 -14.7- 25 µm . Polyactines (Fig. 10G): three-six claded, cladi spined predominantly at the apices; basal cladi pointed, spined more heavily than the lateral cladi, which are provided with prominent bulbous apices, 35 -46- 66 x 5 -8.9- 10 µm . Figure 10. Cyamon koltuni Sim & Bakus, 1986, A1 Californian holotype, USNM 33630, encrusting a rock (scale = 1 cm) A2 Mexican Pacific specimen LEB-ICML-UNAM 1497 B cross section of peripheral region C thick section of basal mass of polyactines D fragments of long thin style D1 microphoto of detail of rounded apex of long thin style E short thin style F short thick styles G three- to five-claded polyactines showing prominent bulbous ending of lateral cladi. Distribution. Southern California, Pacific coast of Mexico. Ecology. Under rocks and in caves in shallow water. Discussion. The enhanced bulbous endings of the polyactines is distinctive and is only matched by those of Cyamon amphipolyactinum sp. n., but that species differs clearly by possessing a smaller category of amphipolyactines. It is generally similar to Cyamon agnani , differing from that species in the sizes of the styles and the very prominent bulbous endings of the cladi of the polyactines.