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Description of a new lithistid sponge from northeastern New Zealand, and consideration of the phylogenetic affinities of families Corallistidae and Neopeltidae

Michelle KELLY

en Zoosystema 22 (2) - Pages 265-283

Published on 30 June 2000

Homophymia stipitata n. sp. is described from continental shelf banks off northeastern New Zealand, and compared with the genus holotype H. lamellosa Vacelet & Vasseur, 1971 from Madagascar. Diagnostic morphological characters for Homophymia are reviewed, expanded, and compared to those of Callipelta Sollas, 1888, Macandrewia Gray, 1859 and Daedalopelta Sollas, 1888 in the dicranocladinid lithistid family Corallistidae. A suite of morphological characters were identified that link these genera with each other and with Neopelta Schmidt, 1880 presently in the monogeneric dicranocladinid family Neopeltidae. Two major diagnostic features characterize this group - the possession of monocrepid megarhizoclone desmas with a distinctive short crepis visible in the epirhabd and modified ectosomal desmas which resemble triaenes. These pseudotriaenes have a short irregularly thickened pseudorhabd in which the crepis is usually located, and the pseudoclads are disc-shaped or polyfurcate. These ectosomal desmas are granular and appear pithed as do the choanosomal desmas, and they lack the triaenose inceptional canals which typify triaenes. The microscleres are spined amphiasters. Homophymia, Callipelta, Macandrewia and Daedalopelta are clearly distinguished from other genera in the Corallistidae (Corallistes Schmidt, 1870; Herengeria Lévi & Lévi, 1988; Iouea Laubenfels, 1955 and the Cretaceous fossils Gignouxia Moret, 1926; Phrissospongia Moret, 1926; Procorallistes Schrammen, 1901) which have arched tuberculate dicranoclone desmas, long-shafted triaenes, and two size categories of spiraster-like streptasters. The integrity of the families Corallistidae and Neopeltidae are evaluated and suggestions put forward for the transfer of Homophymia, Callipelta, Macandrewia and Daedalopelta to the family Neopeltidae.

Keywords :

Porifera, Corallistidae, Neopeltidae, lithistid, Homophymia, Callipelta, Macandrewia, Daedalopelta, Neopelta.

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