Dragmacidon hendersoni Sim-Smith &amp; Hickman &amp; Kelly 2021, sp. nov.
Creators: name: Sim-Smith, Carina
name: Hickman, Cleveland
name: Kelly, Michelle
Publisher: name: Zenodo
Year: 2021
Subjects: Biodiversity
Taxonomy
Animalia
Porifera
Demospongiae
Axinellida
Axinellidae
Dragmacidon
Dragmacidon hendersoni

description: <i>Dragmacidon hendersoni</i> sp. nov. (Fig. 13) <b>Material examined.</b> <i>Holotype —</i> MCCRDS9412, Nameless Island, 0.670° S, 90.586° W, 9 m, 9 Aug 2003. <b>Type locality.</b> Nameless Island; 9 m. <b>Habitat and distribution.</b> Only known from the type locality. Found in a recess on a vertical wall growing on rock; 9 m. <b>Description.</b> Thinly encrusting sponge, 3 mm thick, with a minutely ridged and punctate surface. A few small oscules are scattered over the surface of the sponge. Texture is compressible, surface is faintly hispid. Colour in life is bright yellow, colour in ethanol is tan (Fig. 13A). <b>Skeleton.</b> Choanosomal skeleton is loosely plumoreticulate, with delicate, multispicular primary tracts and vague secondary tracts/connections. Bundles of styles protrude through the surface of the sponge, in tufts, points uppermost. There is no special ectosome (Fig. 13B). <b>Spicules.</b> <i>Megascleres—</i> Style I (Fig. 13C), small, slender and slightly curved; 231 (209–248) × 6 (4–7) µm (n = 20). Style II (Fig. 13D), very slender and often strongly curved or slightly sinuous; 197 (127–334) × 2.4 (1.2–3.4) µm (n = 20). <b>Etymology.</b> Named after Scott Henderson, who accompanied co-author Cleveland Hickman on numerous trips to the Galápagos from 1983–2016. He assisted Cleve in a variety of roles from local negotiator and logistics organiser, divemaster during harrowing high-current dives, trusted friend and host on his Santa Cruz coffee farm. Of the 149 students Cleve led on 12 Galápagos student field trips, Scott was the only one to make Galápagos his home and life-long conservation project. <b>Remarks.</b> <i>Dragmacidon hendersoni</i> <b>sp. nov.</b> differs considerably from <i>D. raeae</i> <b>sp. nov.</b> by: live colouration (yellow vs bright red); skeleton (compact plumoreticulate vs loosely plumoreticulate to plumose); texture (firm vs compressible); and the possession of two size categories of styles, with both categories being more slender and sinuous than those of <i>D. raeae</i> <b>sp. nov</b>. It also differs considerably from the previously recorded <i>D. oxeon</i> which has much longer megascleres. It differs from all other tropical/subtropical eastern Pacific species by the lack of oxeas. Table 4 provides useful details on all known species of <i>Dragmacidon</i>, many of which appear to fall loosely into two groups: those that were previously identified as species of <i>Pseudaxinella</i> Schmidt, 1875 [<i>D. raeae</i> <b>sp. nov.</b> and other species that form firm dome-shaped sponges, with compact plumoreticulate skeletons that often lack trichodragmata, such as <i>D</i>. <i>australe</i> (Bergquist, 1970), <i>D</i>. <i>coccineum</i> (Keller, 1891), <i>D</i>. <i>debitusae</i> (Hooper &amp; Lévi, 1993)]; and those that have a looser, more plumose skeleton with longer, more sinuous megascleres and often raphides in trichodragmata, resulting in a softer, less firm sponge, such as <i>D</i>. <i>oxeon</i>, <i>D</i>. <i>mutans</i> (Sarà, 1978), <i>D</i>. <i>tumidum</i> (Dendy, 1897), and <i>D</i>. <i>decipiens</i> (Wiedenmayer, 1989). The addition of two species from the Galápagos Archipelago, each of which falls loosely into one or the other group, may lend additional data for future detailed analysis of <i>Dragmacidon</i>, a genus of convenience into which all species commonly previously recorded as <i>Pseudaxinella</i> (a junior synonym of <i>Axinella</i>), were assigned by Alvarez &amp; Hooper (2002: 734).
description: Published as part of <i>Sim-Smith, Carina, Hickman, Cleveland &amp; Kelly, Michelle, 2021, New shallow-water sponges (Porifera) from the Galápagos Islands, pp. 1-71 in Zootaxa 5012 (1)</i> on pages 30-31, DOI: 10.11646/zootaxa.5012.1.1, http://zenodo.org/record/5158062
description: {"references": ["Schmidt, O. (1875) Spongien. Die Expedition zur physikalisch-chemischen und biologischen Untersuchung der Nordsee im Sommer 1872. Jahresbericht der Commission zur Wissenschaftlichen Untersuchung der Deutschen Meere in Kiel, 2 - 3, 115 - 120. [in German]", "Bergquist, P. R. (1970) The Marine Fauna of New Zealand: Porifera, Demospongiae, Part 2 (Axinellida and Halichondrida). New Zealand Oceanographic Institute, Wellington, 85 pp.", "Keller, C. (1891) Die Spongienfauna des Rothen Meeres (II. Halfte). Zeitschrift fur wissenschaftliche Zoologie, 52, 294 - 368.", "Hooper, J. N. A. &amp; Levi, C. (1993) Axinellida (Porifera: Demospongiae) from the New Caledonia lagoon. Invertebrate Taxonomy, 7 (6), 1395 - 1472. https: // doi. org / 10.1071 / IT 9931395", "Sara, M. (1978) Demospongie di acque superficiali della Terra del Fuoco (Spedizioni AMF Mares - GRSTS e SAI). Bollettino dei Musei e degli Istituti Biologici della (R.) Universita di Genova, 46, 7 - 117. [in Italian]", "Dendy, A. O. (1897) Catalogue of non-calcareous sponges collected by J. Bracebridge Wilson, Esq., M. A., in the neighbourhood of Port Phillip Heads. Part III. Proceedings of the Royal Society of Victoria, New Series, 9, 230 - 259.", "Wiedenmayer, F. (1989) Demospongiae (Porifera) from northern Bass Strait, southern Australia. Memoirs Museum Victoria, 50 (1), 1 - 242. https: // doi. org / 10.24199 / j. mmv. 1989.50.01", "Alvarez, B. &amp; Hooper, J. N. A. (2002) Family Axinellidae Carter, 1875. In: Hooper, J. N. A. &amp; Van Soest, R. W. M. (Eds.), Systema Porifera: A Guide to the Classification of Sponges. Vol. 1. Kluwer Academic / Plenum Publishers, New York, New York, pp. 724 - 747. https: // doi. org / 10.1007 / 978 - 1 - 4615 - 0747 - 5 _ 80"]}