Dragmacidon cf. australe ( Bergquist, 1970 )

Alvarez, Belinda, De Voogd, Nicole J. & Soest, Van, 2016, Sponges of the family Axinellidae (Porifera: Demospongiae) in Indonesia, Zootaxa 4137 (4), pp. 451-477 : 457-459

Dragmacidon cf. australe ( Bergquist, 1970)

( Fig. 2 , 5 )

Pseudaxinella australis Bergquist, 1970: 20 ; Hooper & Lévi 1993: 1439; Hooper & Wiedenmayer 1994: 80; Alvarez et al. 2000: 196

Dragmacidon australis .— Alvarez & Hooper 2002: 735

Dragmacidon australe .— Alvarez & Hooper 2009: 27

Material examined. HOLOTYPE.— NMNZ Por. 26, Takatu Channel, Northland, New Zealand, 11 m depth. ADDITIONAL SPECIMENS.— RMNH POR. 3610, Indonesia, Bali, NE-side Pulau Serangan, off lighthouse, 8.7213°S, 115.2586°E, 17 m depth, 5 April 2001, #Bali14/NV/ 050401 /75, coll. N.J. de Voogd. RMNH POR. 3615, Indonesia, Bali, SE-end Tulamben beach, 8.2777°S, 115.5958°E, 30 m depth, 12 April 2001, #Bal22/ 110401 /164, coll. N.J. de Voogd. ZMA Por. 18711, Thailand, West of Ko Kudi, Samet Islands, Rayong, 12.57672°N, 101.5094°E, 4 m depth, 28 October 2001, coll. Sumaitt Putchakarn.

Description. Shape ( Fig. 5 A, B). Thickly encrusting and adapting to the substrate shape to massive-globular. Approximately 3–18 cm in diameter and/or 2 cm thick.

Colour. Deep orange to red

Consistency. Hard to incompressible in preserved stage.

Oscula. From inconspicuous or minute, up to 5 mm in diameter, depending on the specimen.

Surface. Brush-like, regularly covered with short and broad conules, fused laterally, creating a microreticulation at surface. Conules end with brushes of spicules.

Skeleton ( Fig. 5 C). Plumoreticulated to halichondroid; formed by thick plumose or plumo-echinated multispicular tracts, up 200–300 µm thick, forming an irregular reticulation of large, rounded to oval meshes. Main tracts connected by shorter and relatively thinner plumose tracts.

Spicules ( Fig. 5 D, Table 4). Oxeas, 332.6–421.6µm x 14.2–24.4 µm and styles 280.2–430.1 µm x 13.4–20.7 µm in similar proportions.

Remarks. The material examined here is very similar in all their morphological and skeletal characteristics to that reported from northern Australia by Alvarez & Hooper (2009). This species is also very similar to Dragmacidon reticulatum ( Ridley & Dendy, 1886) from the Central West Atlantic both in external morphology and spicule composition. A specimen from Thailand was also available for examination and is referred here to D. austral e with some hesitation. This specimen differed from the rest of the material examined in that is thinly encrusting and the reticulation of the skeleton seems to be incomplete and represented only by short plumose tracts ascending from a basal skeleton formed by spicules without any orientation and detritus. Unusual dichotriaenes and lophotriaenes were observed in the basal skeleton but is assumed here these spicules are foreign.

Distribution. Dragmacidon australe was first recorded for New Zealand (Temperate Australasia realm). Additional records from GBR (Tropical Southwestern Pacific province) and northern Australia (Sahul Shelf province) were reported in Hooper & Lévi (1993) and Alvarez & Hooper (2009). This revision extends the distribution range of this species to Western Coral Triangle and Sunda Shelf [?]( Fig. 2 ) provinces of the Central- West Indo-Pacific realm.

The wide distribution of Dragmacidon australe suggests this species might be both a broadcaster and cosmopolitan or it might represent a complex of cryptic species that can be differentiated only with the use of genetic methods. No morphological characters are currently available to distinguish the different geographical populations.

Specimen Locality Oxeas Styles

RMNH POR. 3610 Bali 332.6–421.6µm (372.6±22.6) 280.2–430.1µm (363.7±38.7) x 14.2–24.4µm (18.6±2.3) x 13.4–20.7µm (17.7±1.8) ZMA Por. 18711 Thailand 247.1–414.8µm (332.6±46.4) 268.9–497.6µm (367.2±63.7)

Figures

FIGURE 2. Map showing the geographical location of the described species.

FIGURE 5. Dragmacidon cf. australe. A, RMNH Por. 3610, in situ at Pulau Serangan, Bali. B, RMNH POR. 3615, photographed in situ at Tulamben beach, Bali. RMNH Por. 3610: C light microphotograph of skeleton; D, drawing of spicules. Scale bars: C, 500 µm; D, 50 µm. Photos A – B: Nicole de Voogd.