Penares angeli, Sim-Smith & Hickman & Kelly, 2021

Sim-Smith, Carina, Hickman, Cleveland & Kelly, Michelle, 2021, New shallow-water sponges (Porifera) from the Galápagos Islands, Zootaxa 5012 (1), pp. 1-71 : 36-37

Penares angeli sp. nov.

( Fig. 16 )

Material examined. Holotype — MCCDRS9410, Maria Elena Islet , Pinzón Island, 0.592° S, 90.684° W, 13 m, 20 Jan 2003.

Type locality. Maria Elena Islet , Pinzón Island .

Habitat and distribution. Only known from type locality, growing in a rock crevice; 13 m.

Description. Massive, lobose sponge, with a single, large oscule, 5–8 mm in diameter, on the apex of each lobe. The surface is smooth, almost fleshy. Colour in life dark grey-brown on top fading to white at the base (the colour of the underlying choanosome), colour in ethanol medium brown fading to tan at the base ( Fig. 16A–B ). Texture firm, compressible.

Skeleton. The cortex is approximately 500 µm thick and comprises a dense crust of microrhabds and microxeas that are lying in no particular orientation. A thin, dense layer of microrhabds exists on the surface of the sponge. Regular pores pierce the cortex. Orthotriaenes are arranged perpendicular to the surface with their cladome at the base of the cortex ( Fig. 16C ). Oxyasters, microxeas, and microrhabds are abundantly scattered throughout the choanosome ( Fig. 16D ).

Spicules. Megascleres— oxeas, moderately long and stout, often curved; 1808 (1240–2672) × 31 (19–44) µm (n = 20). Orthotrianes are moderately long with a curved cladome; rhabdome length 1270 (926–1668) µm, protoclad length, 283 (226–367) µm, cladome width, 530 (389–640) µm (n = 20) ( Fig. 16E ). Microscleres— oxyasters, small with several long, slender acanthose rays; 14 (6–26) µm in diameter (n = 20) ( Fig. 16H ). Microxeas are curved and centrotylote, 135 (101–191) × 7 (4–10) µm (n = 20) ( Fig. 16F ). Microrhabds are centrotylote and lightly acanthose; 48 (29–88) × 4 (2–5) µm (n = 20) ( Fig. 16G ).

Etymology. Named after Angel Chiriboga for his invaluable assistance with the collection and photography of the sponges.

Remarks. Four species of Penares have been previously described from the Galápagos Islands: P. saccharis ( De Laubenfels, 1930) , P. scabiosus Desqueyroux-Faúndez & Van Soest 1997 , P. foliaformis Wilson, 1904 , and P. apicospinatus Desqueyroux-Faúndez & Van Soest 1997 . The first three species possess dichotriaenes whereas P. angeli sp. nov. possesses orthotriaenes. Penares apicospinatus has two size classes of oxyasters and oxeas that are much longer (2496 (1426–3130) µm; measurements from Desqueyroux-Faúndez & Van Soest 1997) than those of P. angeli sp. nov.

Figures

FIGURE 16. Penares angeli sp. nov. holotype, MCCDRS9410: A. In situ. B. Deck photo. C. Cross section of the microrhabd and microxea crust in the cortex and the orthotriaenes underneath. D. Cross section of the choanosome showing the scattered microrhabds, microxeas and oxyasters. E. Orthotriaene. F. Microxeas. G. Microrhabds. H. Oxyasters.