Identifying Sponges

Key to California Porifera (Page 117)

( From page 116 B) Strongyles absent. Tylotes-Subtylotes present; Acanthostyles of 1 size class.
Acanthostyles < 200 μm.
Tylotes-Subtylotes: 96-169 μm.
Hymedesmia (Stylopus) arndti (de Laubenfels, 1930)
Sponge: Thin, encrusting to 1- 2 mm thick. Often takes the form of the substrate on which it is found. Consistency: moderately firm. Surface: superficially smooth to somewhat granular; soft, slippery. Oscula: not evident.
Color: Alive: Ochre-yellow, purple, lavender to pink, buff to brown.
Spicules: Megascleres: (1) Acanthostyles: 72 -94-103- 157 um. x 4 -5-6- 7 um. (2) Tylotes-Subtylotes: 96-136-154- 169 um. x 1.0 -2.0-2.5- 3.0 um.
Skeleton: Modified hymedesmoid structure. Acanthostyles with heads embedded in thick basal layer of spongin, are perpendicular rising to surface. Thick tracts of Tylotes to Subtylotes extending to surface. These also often curve and may end up parallel to surface. Often individuals or small bundles of Tylotes-Subtylotes are lying free, most often near surface.
Distribution: California.
Depth: Intertidal to subtidal, 10 m.
Note: Rhaphides reported by de Laubenfels. See page 190b. Was Astylinifer arndti.
Acanthostyles > 200 μm.
Subtylotes: 213 - 260 μm.
Phorbas hoffmanni (Bakus, 1966)
Sponge: Encrusting to 14 mm. Surface: with tubercles 1.5 mm diam., 2 mm high, otherwise superficially smooth. Oscula: 0.75 - 1.5 mm diameter.
Color: Alive: Orange-brown to chocolate-brown. Preserved: Beige.
Spicules: Megascleres: (1) Acanthostyles (may include a few styles): 211 -272-285- 318 um. x 9 -10-11- 14 um. (2)Subtylotes: 213 -234-240- 260 um. x 5 -6-7- 8 um. (3) Styles - Subtylostyles (thin - rare): 199 - 248 um. x 2 - 3 um.
Skeleton: Ectosome: dermal membrane to 15 μm thick on tubercles. Under the membrane in the inter- tubercular areas are individual or clusters of Subtylotes, more or less tangential to surface. Choanosome: irregular ascending Subtylote tracts echinated by Acanthostyles with loose and irregular spicules in between.
Distribution: Central California.
Depth: Deep water.
Note: Needs to be compared to Phorbas californiana. Was formerly Podotuberculum hoffmanni.
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