Identifying Sponges

Key to California Porifera (Page 264)

( From page 263 B) Mean Discoctaster diameter is less than 110 μm.
[A]
Microdiscohexasters are common.
Discoctaster terminals are straight.
cc264A.jpg
Rhabdocalyptus dawsoni (Lambe, 1893)
Sponge: Straight or curved tube or sac; veil of Diactins and Pentactins.
Color: Light yellowish grey in alcohol.
Spicules: Megascleres: (1) Principal Diactins: 4.2 -6.6- 11.4 mm. (2) Thick Prostal Diactins: to 6 cm. (3) Short Diactins: 0.35 -0.78- 1.62 mm. (4) Thorned Hypodermal Pentactins (tangential ray): 0.9 -2.6- 4.1 mm. (proximal ray): 4.8 -6.6- 8.8 mm. Mesoscleres: (1) Dermal Stauractins (ray): 50 -77- 101 um. (2) Dermal Pentactins (tangential ray): 54 -77- 99 um. (proximal ray): 44 -73- 100 um. (3) Gastral Hexactins (ray): 55 -105- 177 um. Microscleres: (1) Oxy-hemihexasters (diameter): 48 -83- 104 um. (2) Discoctasters (diameter): 56 -66- 82 um. (3) Microdiscohexasters (diameter): 17 -21- 28 um.
Skeleton: Composed entirely of loose spicules.
Distribution: Southern and Northern California.
Depth: Deep water.
Note: Data mostly from Syntype CMN 1900-2811;
Prostal Diactin length from Lambe, 1892. Reported to slough outer veil of spicules in winter. Tabachnick's 2002 proposed move of Rhabdocalyptus to a subgenus of Acanthascus is not followed here.
[B]
Microdiscohexasters are NOT present.
Discoctaster terminals are strongly curved resulting in flared terminal bundles.
Rhabdocalyptus tener Schulze, 1899
Sponge: Known only from incomplete lower part; probably tube or sac-shaped.
Color: Not reported.
Spicules: Megascleres: (1)Principal Diactins: 3.2 -7.3- 13.1 mm. (2)Thick Prostal Diactins: to 2.1 cm. (3)Short Diactins: 0.60 -1.37- 2.92 mm. (4)Thorned Hypodermal Pentactins (tangential ray): 1.6 -2.6- 4.1 mm. (proximal ray): 5.2 -5.8- 7.6 mm. Mesoscleres: (1) Dermal Stauractins (ray): Length-ray 61 -89- 137 um. (2) Dermal Pentactins (tangential ray): 68 -103- 130 um. (proximal ray): 76 -112- 149 um. (3) Gastral Hexactins (ray): 87 -157- 252 um. Microscleres: (1)Oxyhexactins (diameter): 68 -86- 104 um. (2)Oxyhexasters and Oxyhemihexasters (diameter): 62 -84- 119 um. (3)Discoctaster (diameter): 71 -85- 110 um.
Skeleton: Composed entirely of loose spicules.
Distribution: Southern California.
Depth: Deep water.
Note: Data from Holotype USNM 7577. See note above.
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