Family PODOSPONGIIDAE de Laubenfels, 1936

Museums

Regional Maps

Introduction

This family was resurrected recently by Kelly & Samaii (2002) based on the recognition by Kelly-Borges & Vacelet (1995) of the non-homologous nature of 'latrunculiid' microscleres, and supported by clear differences in the arrangements of their megasclere skeletons. Two distinct taxa emerged: Latrunculiidae, which includes species containing discate acanthose microrhabds (acanthodiscorhabds) that develop from a straight protorhabd, and located in a tightly packed palisade in the ectosomal membrane, with anisotyle megascleres arranged in a wispy reticulation, and an ectosomal skeleton containing tangentially orientated megascleres; and Podospongiidae, with species possessing spinose or discate microscleres (spinorhabds) with a sigmoid protorhabd, oxeote or stylote megascleres forming a plumoreticulate radiating skeleton, and an elaborate ectosomal skeleton dendritic tracts arising from the apices of primary fibres. There are four valid genera, Podospongia, Sigmosceptrella, Diacarnus, and Negombata.

Diagnosis

Thickly encrusting, digitate branching, massive tubular, vasiform to stipitate sponges with microscopically smooth conulose surface, and membranous oscules. Texture is tough, rubbery (almost cartilaginous in Diacarnus), compressible and fleshy to the touch. Colour in life is uniformly tan with surface pigmentation of maroon and oak brown (Sigmosceptrella, Diacarnus), brilliant orange red (Negombata), or creamy to orange (Podospongia). Structural megascleres include strongyloxeas (often vestigial in Diacarnus), robust curved anisostrongyles (Negombata) or more typically variants of styles, strongyles and oxeas (Podospongia). Ectosomal skeleton with characteristic plumose ‘starbursts’ of spicule tracts, with fine, dendritic individual tracts arising from the ascending choanosomal fibres and expanding into tiny brushes in the ectosomal membrane (most elaborate and umbelliform in arrangement in Diacarnus and Sigmosceptrella). Choanosomal skeletal architecture dominated by huge thick hollow primary fibres interconnected by occasional short secondary fibres forming extremely elongate narrow meshes (in Diacarnus and Sigmosceptrella), or fibroreticulate, forming a tight-meshed square reticulation of anisostrongyles incorporated into clear fibres (in Negombata). Microscleres are spinorhabds, often in two size categories, with two whorls of spines arranged serially around the spicule, between a proximal and distal whorl of spines, one of which may be longer than the other. The protorhabd is sigmoid in Sigmosceptrella, Negombata, and Podospongia. Microscleres are typically arranged in a compact crust or are scattered throughout the ectosomal region, with smaller categories also present in the choanosome. Where known reproduction is viviparous, producing huge bright yellow-orange larvae throughout the year that are clearly visible to the unaided eye. Diacarnus and Sigmosceptrella are known to produce the biologically active compounds norsesterterpene peroxides, and Negombata produces latrunculins.

ID Keys

KEY TO GENERA
(1) Choanosomal tracts radiating from a centrum, stipitate body ----------------------------------------- Podospongia
Plumoreticulation ------------------------------------------------------------------------------------------------------------------ 2

(2) Megascleres styles in addition to strongyloxeas ----------------------------------------------------------- Negombata
Megascleres strongyloxeas only ------------------------------------------------------------------------------------------------ 3

(3) Megascleres strongyloxeas with various tornote, oxeote or stylote modifications ---------------------------------- 4
***

(4) Huge hollow primary fibres with umbelliform ectosomal skeleton, protorhabds of microscleres straight -------------------------------------------------------------------------------------------------------------------------- Diacarnus
Thick dense primary tracts with robust ectosomal tracts, surface crust of spinorhabds, protorhabds of microscleres
sigmoid -------------------------------------------------------------------------------------------------------- Sigmosceptrella

Diagnosis References

Kelly, M. & Samaai, T. 2002. Family Podospongiidae de Laubenfels, 1936. pp. 694-702 in Hooper, J.N.A. & van Soest, R.W.M. (eds). Systema Porifera: A guide to the classification of sponges. New York : Kluwer Academic/Plenum Publishers Vol. 1. [694]

General References

Kelly, M. & Samaai, T. 2002. Family Podospongiidae de Laubenfels, 1936. pp. 694-702 in Hooper, J.N.A. & van Soest, R.W.M. (eds). Systema Porifera: A guide to the classification of sponges. New York : Kluwer Academic/Plenum Publishers Vol. 1.

Kelly-Borges, M. & Vacelet, J. 1995. A revision of Diacarnus Burton and Negombata de Laubenfels (Demospongiae: Latrunculiidae) with descriptions of new species from the west central Pacific and the Red Sea. Memoirs of the Queensland Museum 38(2): 477-503

History of changes