Polymastia pacifica Lambe, 1893 b

Austin, William C., Ott, Bruce S., Reiswig, Henry M., Romagosa, Paula & G, Neil, 2014, Taxonomic review of Hadromerida (Porifera, Demospongiae) from British Columbia, Canada, and adjacent waters, with the description of nine new species, Zootaxa 3823 (1), pp. 1-84: 28-31

publication ID

http://dx.doi.org/10.11646/zootaxa.3823.1.1

publication LSID

lsid:zoobank.org:pub:0D42FA17-3B11-4DBB-9E48-D7D505F9CE29

persistent identifier

http://treatment.plazi.org/id/03D0FB0A-FF92-2E0C-09E0-FBF4FD947AFF

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scientific name

Polymastia pacifica Lambe, 1893 b
status

 

Polymastia pacifica Lambe, 1893 b 

Fig. 9View FIGURE 9 A –G

Non Polymastia pacifica Koltun, 1966  , a junior synonym.

Material examined. Holotype: CMN 1900-2885, near Comox, Strait of Georgia, BC, (approx. 49 º 42 ′N, 124 º 50 ′W), 73 m depth, Jun. 24, 1885, coll. G. M. Dawson.

Other material: KML 1026, KML sta. 19 / 76, Princess Royal Reach, Jervis Inlet, BC, (50 º 01.0′N, 123 º 56.5 ′W) 30, 70 m depth, Mar. 15, 1976, coll. W.C. Austin; KML 1027, sta. 25 / 76, entrance to Prince of Wales Reach, Jervis Inlet, BC, (49 º 47.6 ′N, 123 º 56.8 ′W), Mar. 16, 1976; coll. W.C. Austin; KML 1028, KML sta. 27 / 76, Cullodon Point, Jervis Inlet, BC, (49 º 47.5 ′N, 124 º 04.6′W), no depth, Mar. 17, 1976, coll. W.C. Austin; KML 1029, KML sta. 137 / 76, S. of Swale Rock, Barkley Sd., BC, (48 º 55.0′N, 125 º 13.1 ′W), 45, 52 m, depth, Aug. 3, 1976, coll. W.C. Austin; KML 1337, NM 291, Croker I., Indian Arm, BC, (49 ° 25.76 ′N, 121 ° 51.89 ′W), 15 m depth, Sept. 20, 2012, coll. N. McDaniel; KML 1339, NM 292, Croker I., Indian Arm, BC, (49 ° 25.76 ′N, 121 ° 51.89 ′W), 15 m depth, Sept. 20, 2012, coll. N. McDaniel; KML 1340, NM 293, Croker I., Indian Arm, BC, (49 ° 25.76 ′N, 121 ° 51.89 ′W), 15 m depth, Sept. 20, 2012, coll. N. McDaniel.

Field images, KML 1030, Pulalli Point, South Fingers Wall, Dabob Bay, Hood Canal, Washington, (47 º 44.0′N, 122 º 51.2 ′W), 20–30 m depth, Apr. 4, 2009, coll. & photo Janna Nichols, Greg Jensen; KML 1337, NM 291, Croker I., Indian Arm, BC, (49 ° 25.76 ′N, 121 ° 51.89 ′W), 15 m depth, Sept. 20, 2012, photo N. McDaniel.

Description. Macroscopic features. ( Fig. 9View FIGURE 9 A). Sponge forming encrustations 7–30 mm long by 7–12 mm wide by 2–10 mm thick. Fistulae largely cylindrical but some slightly flattened, 2–7 (occasionally to 15) mm high and 1.5–2 mm in diameter. Number of fistulae from 1 per smallest sponge to 18 in largest sponge observed. Oscula at the summit of some fistulae, 0.5–1 mm diameter; other fistulae appearing blind. Surface hispid from projecting spicules; surfaces of fistulae basally microhispid and apically smooth. Consistency firm and only slightly compressible. Live colour: fistulae beige to white, basal part brown due to entrapped silt.

Microscopic features, ( Fig. 9View FIGURE 9 B, 9 C). Ectosome composed of cortical layer 0.5 mm thick, nearly cartilaginous. Palisade of tylostyles of all sizes embedded in cortex, apices outward; short tylostyles concentrated in ectosome. Long thin subtylostyles II with apices projecting outward up to 1 mm from main sponge body, originating in choanosome. Fistulae supported by tracts of short tylostyles. Tracts forming distinct canals in fistulae, terminating in osculum at apex. Tylostyles apically arranged more or less in parallel with long axis of fistulae with majority of apices pointing up. Tylostyles penetrating surface of fistulae basally up to 300 µm and main body up to 700 µm. Choanosome with long styles to subtylostyles I in radiating tracts 100–200 µm thick with intermediate and small tylostyles in random distribution throughout. Disposition of long, thin, surface-echinating subtylostyles at right angle to surface. No apparent basal specialization of choanosomal skeleton.

Spicules. Spicule complement including very long, thin styles to subtylostyles I echinating the main sponge body ( Fig. 9View FIGURE 9 D), long, thin subtylostyles II ( Fig. 9View FIGURE 9 E –F), long thin tylostyles I ( Fig. 9View FIGURE 9 G) and shorter fusiform, occasionally bent, tylostyles II ( Fig. 9View FIGURE 9 I,) with well developed heads; both tylostyles occasionally polytylote. Tylostyles II occasionally with subterminal heads ( Fig. 9View FIGURE 9 J). Spicule measurements from five specimens are listed in Table 7.

Remarks. Lambe (1893 a) described four spicule types, viz. two types of subtylostyles (739– 1205 x 13–19 Μm, forming radial multispicular tracts, and 1000–3000 Μm, echinating the main body surface), and two types of tylostyles (191–630 x 19 Μm in the inner cortex, and 108 x 6 Μm, forming a palisade in the ectosome and scattered in the choanosome). The smaller tylostyles II that we measured fit Lambe’s ectosomal tylostyles and are located in this position in our specimens. The long subtylostyles (to 2500 Μm in our specimens) echinate the body and are not found in the fistulae.

Polymastia pacifica  is here distinguished from P. pachymastia  based on its distribution (ranging from shallow [15 m] to deep [at least 100 m] for P. pacifica  vs. mostly shallow to intertidal for P. pachymastia  ) and spicule compliment ( pachymastia  : 2 styles to subtylostyles, 3 tylostyles; pacifica  : 2 subtylostyles, 2 tylostyles). Polymastia pacifica  has invariably small (0.5–3 mm basal diameter) fistulae, whereas P. pachymastia  has many large (1–2 cm basal diameter) fistulae. Very small individuals of Polymastia pacifica  typically have only one or two fistulae. The fistulae of P. pachymastia  are conical (L/W <2.2) while in P. pacifica  they are cylindrical (L/W> 3). Polymastia pacifica  fistulae are similar to small P. toporoki  but, unlike P. toporoki  , fistulae do not grow close together in larger specimens; P. pacifica  has four types of spicules (two tylostyles and two subtylostyles to styles), whereas P. toporoki  has only two types of tylostyles.

Polymastia pacifica  reported for the Aleutians ( Stone et al. 2011) is bright orange in life and several cm thick which is uncharacteristic of any specimens we have examined which are white with the main body usually discoloured brown from sediment and a main body a few mm thick.

Conclusions. There are no other Polymastia  species recorded from the north Pacific which have small, cylindrical fistulae. We conclude that Polymastia pacifica  is a distinct species. The synonymy of Polymastia pacifica Koltun 1966  not Lambe 1893 b needs to be addressed.

Bathymetric range. From 15 to at least 180 m depth.

Geographic distribution. Southern British Columbia in Jervis Inlet, Indian Arm, Barkley Sd., Comox and in Hood Canal (Washington). Records from southern California ( Green & Bakus 1994) are based on the supposition that presence of small tylostyles in the cortex palisade excludes P. pachymastia  , and their material probably represents P. pacifica  . Records from the Aleutian Islands, Alaska may not be this species (see previous comment).

Ecology. This species occurred on dead hexactinosan sponges in Jervis Inlet in areas where currents are weak. It also occurred on rocks at Pulali Point, Hood Canal, which has only weak currents and in similar conditions in Indian Arm and Sechelt Inlet, BC.

TABLE 7. Polymastia pacifica Lambe, 1893, spicule dimensions.

      100
      100
      100
      100
      100
      100
      100
  1100–(1647)–2325 10.0–(14.3)–20.0  
      100
      100
CMN

Canadian Museum of Nature

Kingdom

Animalia

Phylum

Porifera

Class

Demospongiae

Order

Hadromerida

Family

Polymastiidae

Genus

Polymastia

Loc

Polymastia pacifica Lambe, 1893 b

Austin, William C., Ott, Bruce S., Reiswig, Henry M., Romagosa, Paula & G, Neil 2014
2014
Loc

Polymastia pacifica

Koltun 1966
1966