Zosterocarpus abyssicola is a species of brown algae endemic to the Galapagos islands.
This is a very inconspicuous species and hard to identify, so much that it is only known from its collection of types.[1] The only specimens were collected in 1934 at Post Office Bay by Floreana Island in the Galápagos Islands, and the species is considered endemic to the area.[2] A 2007 search failed to find any further specimens.[1]
The specific epithet abyssicola derives from the Greek ἄβυσσος (ávyssos) and Latin -cola, meaning one who inhabits the abyss. However, it has only been found at 55 meters depth,[2] and is photosynthetic, so the name is hyperbole.
The thallus is a light green-brown and 1-2 cm tall.[2] The form is rather diffuse and spreading, without a persistent main axis.[2] The cells of the major branches are thin-walled, cylindrical, and 32 μm in diameter and 58-65 μm long.[2]
The characteristic oval brown cells were assumed to be the sporangia by Taylor,[2] but are special tannin-filled cells.[3] These are scattered throughout the upper thallus, but solitary, measuring about 30 μm in diameter and 68-70 μm long.[2] They contain oval-shaped bodies.[2]
The gametangia are in clusters of 4-6 cells and only 6-8 μm in diameter.[2]
The species lacks phaeophycean "hairs" and the parenchyma is weakly developed.[3] It is more slender than Z. oedogonium, and the brown tannin cells for the former are wider than the rest of the filaments, ad opposed to the same size.[2] Z. ogasawaraensis and Z. australicus lack these special cells.[3] The latter two also have laterals that arise from single sells on the filaments and not from the septa between cells like the former two species.[3]
The species is an epiphyte.[2] It is thought to be eaten by sea urchins.[1]
It has been evaluated by the IUCN as data deficient, and is one of only fifteen protists evaluated by IUCN.[1] Like Desmarestia tropica, another William Randolph Taylor find from the same expedition, it is threatened by warming ocean temperatures and overgrazing by sea urchins.[1]
Zosterocarpus abyssicola is a species of brown algae endemic to the Galapagos islands.