New species ofMicrosclerodermaandAmphibleptula(Demospongiae, Tetractinellida, Scleritodermidae) from two contrasting marine environments

Abstract

We record for the first time a nominal species of the genus Microscleroderma in the Western Atlantic, and the first record of the genus Amphibleptula in Mexico. Two new species of ‘lithistid’ Tetractinellida are described: Microscleroderma mexica sp. nov. from crevices of two reefs in Veracruz, Mexico, and Amphibleptula aaktun sp. nov. from the anchialine cave El Aerolito, Cozumel Island, Mexico. Microscleroderma mexica sp. nov. is characterized by its tubular and cup-shaped to wavy laminar habitus, hirsute surface and two size categories of oxea diactines. Amphibleptula aaktun sp. nov. is characterized by its ficiform or lobular habitus with an exhalant area at the flat top of the body, divided into numerous vertical septa-like structures; its desmas have thinner epirhabds, and thinner oxea than those of Amphibleptula madrepora. This is the second species of Amphibleptula that has been described; hence, we propose the redefinition of the genus. Both species described have a shallow distribution (≤21 m depth); they are differentiated from each other by the disjunction between their habitats as well as by their morphology.

New genus and species of lithistid demosponges from submarine caves in Nuku Hiva (Marquesas Islands) and Tahiti Iti (Society Islands), French Polynesia

“…It is postulated that the majority of these sponges were originally shallow water sponges that moved into deeper waters as silica concentrations decreased in shallow water (Pisera 2004). Few records exist of lithistid cave fauna occurring outside the Mediterranean Sea (Gerovasileiou et al 2016;Gómez et al 2021). Some lithistids were described from shallow crevices in coral reefs of Madagascar (Vacelet & Vasseur 1965), from the central western Atlantic in Belize and Fernando de Noronha (Muricy & Minervino 2000), and a few more were observed in a large submarine cave on Palawan in the Philippines, which represents the only known record of cave lithistids so far in the Pacific Ocean (Pisera & Vacelet 2006).…”