Tube morphology, ultrastructures, and mineralogy in recent Spirorbinae (Annelida: Polychaeta: Serpulidae). IV. Tribe Romanchellini
Year: 2024
Type: article
Abstract: This is the fourth paper of the series (see Ippolitov & Rzhavsky, 2014, 2015a, b) that provides descriptions of the morphology of tubes of Recent spirorbins, their mineralogies and ultrastructures.Here, we discuss members of the tribe Romanchellini P. Knight-Jones, 1978 which comprises genera Eulaeospira Pillai, 1970, Helicosiphon Gravier, 1907a (including Knightjonesia Pillai, 2009), Metalaeospira Pillai, 1970, Protolaeospira Pixell, 1912 and Romanchella Caullery et Mesnil, 1897.Romanchellini's tube ultrastructures demonstrate an outstanding variability, which includes three types of unoriented structures (irregularly oriented prismatic -IOP, with several subtypes of crystal fabric described for the first time; spherulitic irregularly oriented prismatic -SIOP; rounded homogeneous crystal -RHC) and three types of oriented and semi-oriented structures (oriented fibrillar -OF; spherulitic prismatic -SPHP; simple prismatic -SP).Mineralogically, all studied tubes are 100% calcitic, with doubtful aragonite content registered in sample.Based on tube morphology, ultrastructures, and mineralogy, all Romanchellini can be subdivided into four groups, roughly corresponding to the subdivision into genera.Genus Eulaeospira differs from most other members of the tribe and should possibly be re-installed within the tribe Paralaeospirini, as was proposed by Phyllis Knight-Jones in her early papers.In the genus Protolaeospira, thick tubes, strengthened by the dominance of SP/SPHP structures, are an evolutionary adaptation to the environments characterised by aggressive hydrodynamics and sand abrasion -in particular, to the settlement on rocky substrates and pebbles in the upper sublittoral zone.In contrast, thin walls of tubes in Metalaeospira, also characterised by "loose" microstructure, are likely to relate to settlement on algae.How to cite this article: Ippolitov A.P.,
Source: Invertzool
Authors: A. P. Ippolitov, A. V. Rzhavsky
Institution: Victoria University of Wellington
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W4407108436