Ancorina globosa, Kelly, Michelle & Sim-Smith, Carina, 2012

Kelly, Michelle & Sim-Smith, Carina, 2012, A review of Ancorina, Stryphnus, and Ecionemia (Demospongiae, Astrophorida, Ancorinidae), with descriptions of new species from New Zealand waters, Zootaxa 3480, pp. 1-47 : 12-13

Ancorina globosa sp. nov.

( Fig. 1 D, 4N–Q, 8)

Material examined. Holotype ― NIWA 76782: NIWA Stn TAN0907/8, Campbell Rise, 52.732° S, 170.117° E, 321 m, 0 8 Sep 2009. Paratype ― NIWA Stn NIWA 62464: TAN0907/8, Campbell Rise, 52.732° S, 170.117° E, 321 m, 0 8 Sep 2009.

Type locality. Northern flank of Campbell Rise, Campbell Plateau.

Distribution. Only known from the type locality.

Description. Spherical sponge, free-living, 70–80 mm diameter, with an apical tear-shaped slanted depression, 15–20 mm deep, rim partially fringed with spicules, Ectosome, well-defined, about 1 mm deep, oscules or ostia not visible ( Fig. 1 D). Surface macroscopically smooth, rough and sandpapery to the touch, internal texture elastic, dense, compressible, can be torn. Surface often incorporates rubble and pieces of coral. Colour in life and in ethanol, cream to tan.

Skeleton. Ectosome is about 1000 µm deep, well differentiated from the underlying choanosome by a thick collagen-rich band above the ectosome/choanosome boundary. The ectosome is translucent, with radiating brushes of dichotriaenes, the end of the rhabdomes just entering the choanosome, the cladomes uppermost. The surface is a dense crust of microscleres, about 100 µm thick, enveloping the cladomes of the dichotriaenes. Large oxeas radiate in tight bundles within the choanosome. Large and small oxyasters are common in the choanosome.

Skeleton. Megascleres ( Fig. 4 N) are oxeas, very large, fusiform, 3100 (2474–3539) x 52 (41–66) µm; dichotriaenes ( Fig. 4 N), very large with a broad, flat cladome. Rhabdome length 2803 (2033–3285) µm, cladome width 456 (256–552) µm, protoclad length 133 (103–163) µm, deutroclad length 124 (85–193) µm.

Microscleres ( Fig. 4 O–Q) are oxyasters I ( Fig. 4 O) with about 9 acanthose conical rays, 23 (15–29) µm diameter; oxyaster II ( Fig. 4 P), with a thick centrum and smooth spines, 5 (4–7) µm diameter; sanidasterhabds ( Fig. 4 Q), with acanthose irregular spines, frequently with one or two central restrictions, producing a dumbbell, or trilobed shape overall, 6 (5–7) µm long, occasional amphiaster-like, or cruciform modifications.

Substrate, depth range, and ecology. Apparently free-living on seabed, frequently with coral and other rubble incorporated on the surface of the sponge, silty slope, 321 m.

Etymology. Named for the spherical shape of the sponge ( globosa = Latin for spherical).

Remarks. Ancorina globosa sp. nov. has a unique morphology amongst New Zealand species in the genus; the holotype and paratype are almost perfectly spherical with a fringed slanting apical depression. This species provides the southern-most record for the genus in southern waters ( Fig. 8 ), having not been recorded at any other location. The sanidasterhabds of this species are reminiscent of those of A. diplococcus and A. stalagmoides in that they are dumbbell-shaped, and A. bellae sp. nov. in that they are occasionally cruciform. However, the majority of the microscleres in A. globosa sp. nov. are uniquely trilobed, with two restrictions along the shaft of the spicule. The oxyaster II category is also unique amongst New Zealand species in that they are heavily siliceous and spherasterose. In terms of megasclere dimensions, A. globosa sp. nov. has the second longest oxeas and dichotriaenes of New Zealand species (Table 3). Noteably, there are no anatriaenes as in A. bellae sp. nov. and protriaenes as in A. stalagmoides .

Three of the four New Zealand species of Ancorina have a second larger category of oxyasters in the choanosome, a character present in over half of the 11 species considered to belong to Ancorina worldwide (Table 3). In the current diagnosis, Uriz (2002) notes the presence of oxyasters in Ancorina , but does not specify the presence of two size categories of microsclere. We have observed that over half of the species of Ancorina in Table 3 ( multistella , stalagmoides , bellae sp. nov., globosa sp. nov., repens , and some specimens of cerebrum , e.g. Marenzeller (1889); Stelletta boglicii Schmidt, 1862 ; S. immunda Schmidt, 1862 ) have a distinct, larger category of oxyaster , while two species do not (brevidens, radix). Interestingly, the final three species ( diplococcus , corticata , nanosclera) report only a single category, but these have a considerable size range, indicating the potential for two size classes to be recovered under greater scrutiny.

Figures

FIGURE 1. New Zealand species of Ancorina and Ecionemia: A. Ancorina diplococcus (Dendy, 1924), NIWA 62048, ex situ, scale = 1 cm; B. Ancorina stalagmoides Dendy, 1924, NIWA 49896, ex situ, scale = 5 cm; C. Ancorina bellae sp. nov., holotype NIWA 62005, in situ, scale = 5 cm; D. Ancorina globosa sp. nov., paratype NIWA 62464, preserved, scale = 4 cm; E. Ecionemia alata (Dendy, 1924), NIWA 62217, loaf form, in situ, scale = 10 cm; F. Ecionemia alata (Dendy, 1924), meandering cup form, Spirits Bay, in situ, 80 m, scale = 40 cm; G. Ecionemia novaezealandiae (Dendy, 1924), NIWA 44221, pumpkinshaped form, preserved, scale = 5 cm; H. Ecionemia novaezealandiae (Dendy, 1924), NIWA 62156, tuberose form, ex situ, scale = 5 cm.

FIGURE 4. Megascleres and microscleres of New Zealand species of Ancorina: Ancorina diplococcus, NIWA 62048: A. dichotriaene, scale = 500 µm; B. oxyaster I, scale = 10 µm; C. dumbbell-shaped sanidasterhabds, scale = 5 µm. Ancorina stalagmoides, NIWA 49896: D. protriaene, scale = 500 µm; E. prodichotriaene, scale = 500 µm; F. oxyaster I, scale = 10 µm; G. oxyaster II, scale = 5 µm; H. dumbbell-shaped sanidasterhabds, scale = 5 µm. Ancorina bellae sp. nov., NIWA 62005: I. prodichotriaene, scale = 500 µm; J. anatriaene, scale = 200 µm; K. oxyaster I, scale = 20 µm; L. oxyaster II, scale = 10 µm; M. cruciform sanidasterhabds, scale = 5 µm. Ancorina globosa sp. nov., NIWA 76782: N. dichotriaene, scale = 500 µm; O. oxyaster I, scale = 20 µm; P. spheraster-shaped oxyaster II, scale = 4 µm; Q. dumbbell-shaped sanidasterhabds, scale = 6 µm.

FIGURE 8. Global distribution of Stryphnus, Ancorina, Ecionemia and Stellettinopsis species. Inset = distribution around New Zealand.