A three‐dimensional geometric morphometric study of the development of sulcus versus shell outline in Permian neospiriferine brachiopods

Abstract

2018: A three-dimensional geometric morphometric study of the development of sulcus versus shell outline in Permian neospiriferine brachiopods. Lethaia, Vol. 51, pp. 1-14.The morphological variation of the sulcal development and shell outline in large Permian neospiriferine brachiopods including Fasciculatia Waterhouse, 2004 is investigated using geometric morphometrics. The sulcal tongues of spiriferide brachiopods can be, in a qualitative sense, categorized into three types according to the degree of their development: short sulcal tongue, long sulcal tongue and geniculated sulcal tongue. All three types have been noted within Fasciculatia striatoparadoxa, regardless of the nature of the substrate which they originally inhabited. To quantify its morphological variation both in sulcal development and shell outline, 51 brachiopod shells were scanned with a three-dimensional (3-D) surface imaging device, and their 3-D models were reconstructed. Using two landmarks and 58 semilandmarks designated on the surface of the reconstructed 3-D models, a landmark-based morphometric analysis was performed. Our result demonstrates a significant intraspecific variation of sulcal development in F. striatoparadoxa and its relatives. Local environmental factors, especially the intensity of ambient water flow, are invoked as the most likely cause for this intraspecific variation. Additionally, this study also shows that there are considerable interspecific distinctions in shell outline among Fasciculatia species, independent of the high variation in the sulcal development. The strong stability of overall shell outline at species level implies a decoupled morphological development between sulcal tongue and whole shell outline. The 3-D morphometric approach applied here demonstrates its great utility as a tool for quantifying and analysing the morphological variation of highly convex brachiopod shells. □ Fasciculatia, geometric morphometrics, surface scanning, spiriferide brachiopod, sulcal development, three-dimensional landmark.Sangmin Lee ✉ [sangminlee76@gmail.com], and G. R. Shi [grshi@deakin.edu.au],

Phylogenetic and ecomorphologic diversifications of spiriferinid brachiopods after the end-Permian extinction

“…Increasing evidence shows that, for spiriferiformis, the variation of shell outline and depth of the sulcus can provide a variety of preferential conditions to generate a robust passive feeding flow along the spiral feeding organs (Shiino 2010; Shiino and Kuwazuru 2010, 2011; Lee et al 2018). Other functional structures such as the development of shell thickening, ventral interarea, and shell size work together to help them adapt to various seawater conditions (Shiino and Angiolini 2014).…”

Review of close-range three-dimensional laser scanning of geological hand samples

“…The differences between scans of various species were calculated using Discrete Procrustes distance and three species of blastoid were accurately distinguished. Lee et al (2018) used a NextEngine 3D laser scanner to scan and study 51 brachiopod specimens with a high convexity, which made 2D analysis difficult. The 3D morphometric approach allowed for the quantification and analysis of highly convex brachiopod shells and the developed technique could potentially be applied to other taxa, as well.…”

“…Morphology, the study of structure or form, of geological hand samples, including fossils, rocks, minerals, and sediments, has a variety of applications. For instance, the morphology of fossils aids in the identification of species (Lyons et al, 2000;Arakawa et al, 2002;Bethoux et al, 2004;Lee et al, 2018) and simulations of locomotion (Rybczynski et al, 2008;Evans and Fortelius, 2008;Polly and MacLeod, 2008). For handspecimen sized rock samples, the roughness of its surface or joints allow for the calculation of shear strength (resistance of rock joints to shearing) and transmissivity (ability of water to travel through joints) (Lanaro et al, 2000;Fardin et al, 2001;Hong et al, 2008;Yang and Kulatilake, 2019).…”

Quantifying shell outline variability in extant and fossilLaqueus(Brachiopoda: Terebratulida): are outlines good proxies for long-looped brachidial morphology and can they help us characterize species?

“…Nonetheless, outlines have been used as qualitative features to describe and differentiate species of Laqueus , for example, Laqueus quadratus Yabe and Hatai, 1934; Laqueus rubellus obessus Yabe and Hatai, 1936; and Laqueus pacificus Hatai, 1936 (for a review of Japanese species of Laqueus , see Hatai 1940). The quantitative analysis of shell shape, with emphasis on valve outlines, has been applied to brachiopods to answer questions regarding overall morphological diversity (Smith and Bunje 1999), outline variation and taxonomic designations (Tort 2003; Bose 2012), substrate–shell shape relationships (Alexander 1975; Topper et al 2017), and fold/sulcus development (Lee et al 2018), as well as brachidial variability (Lee et al 2001).…”