Scutelluid trilobites from the Silurian of New South Wales

Holloway, David J.; Lane, P.D

doi:10.1111/j.1475-4983.2012.01132.x

Cited by 14 publications

(56 citation statements)

References 35 publications

(50 reference statements)

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“…cylindrical at best), may invite the systematic position of Paralejurus within the Scutelluidae to be reconsidered. At first sight, illaenimorph traits such as a high convexity of the exoskeleton, a broad axis and a rather high degree of effacement of furrows together with the capacity of complex volvation might indicate close phyletic relationships with effaced late styginids of the Rhaxeros group (Lane and Thomas 1980;Holloway and Lane 1998) and especially Liolalax Holloway and Lane 1999 (see discussion in Schraut and Feist 2004). However, as pointed out by Whittington (1999) and Schraut and Feist (2004), the scutelluids differ from the styginids in having a different pattern of glabellar impressions, articulating half-rings with terrace ridges, hinges on the adaxial pleurae, and 7 paired pleural ribs besides a single, often bifurcated, median one in the pygidium, all features displayed by Paralejurus.…”

Section: Systematic Position Of Paralejurusmentioning

confidence: 98%

Coaptative devices, enrollment, and life habits in Paralejurus, a particular case in scutelluid trilobites

Feist

Lerosey‐Aubril

Johnson³

2010

Palaeobio Palaeoenv

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The first completely enrolled adult scutelluids assigned to the Paralejurus brongniarti group (Pragian) and to Paralejurus rehamnanus (Emsian) from southern Morocco are described. The Pragian taxon exhibits volvation in the sphaeroidal mode and a simple morphological configuration of the external thoracic pleurae with edge to edge fit between each other and against both the posterior edge of the genae and the anterior edge of the pygidium, respectively. Evolutionary trends towards perfect tightness of enrollment and the avoidance of lateral shearing are obvious in later Moroccan Paralejurus such as P. rehamnanus and allies from the Lower/Middle Devonian transition. In these forms, coaptative devices, such as submarginal grooves on the posterior edges of the genae and external thoracic pleurae, ventral fulcral processes and sockets, as well as bulging of the anterolateral pygidial doublures and corresponding depressions in genal doublures, were developed. The possible role of terrace ridges to assist in coaptation and/or to obtain hermetic closure of articulation gaps during volvation is discussed. Morphological and behavioural traits point to a semi-endobenthic lifestyle of Paralejurus with enrollment being an exceptional defence strategy against predatory attack. These traits that differentiate Paralejurus from all other scutelluid taxa are regarded as ecological rather than phylogenetical in origin. Consequently, the assignment of Paralejurus to the subfamily "Paralejurinae" within the Scutelluidae is favoured.

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Section: Systematic Position Of Paralejurusmentioning

confidence: 98%

Coaptative devices, enrollment, and life habits in Paralejurus, a particular case in scutelluid trilobites

Feist

Lerosey‐Aubril

Johnson³

2010

Palaeobio Palaeoenv

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“…Kobayashi & Hamada 1974;Ehiro & Kanisawa 1999;Holloway & Lane 2012;Tanaka et al 2012Tanaka et al , 2013Cocks & Torsvik 2013). To some extent the level of species endemicity may simply reflect the current understanding of, for example, trilobite and brachiopod taxonomy, and much of the fauna clearly requires revision (see, for example, revisions to the trilobite taxonomy presented by Holloway & Lane 1998. The palaeogeographical relationships of the Japanese terranes that preserve Ordovician, Silurian and Devonian sedimentary deposits remains problematic (Metcalfe 2006), not least because of the apparently mixed palaeontological signals.…”

Section: Introductionmentioning

confidence: 93%

“…Metcalfe (2006; see also Aitchison et al 1991) considered the Early and Middle Palaeozoic faunas and floras of the Kurosegawa Terrane to have affinities with Australia and suggested a north Australian Gondwanan margin origin for this terrane. Analysis of trilobites from the Silurian of New South Wales has identified probable conspecific species of the widespread trilobite genus Japonoscutellum (J. magnum and J. diascetum) with the Kurosegawa Terrane, and Bumastella spicula is a confirmed link between the two regions (Holloway & Lane 1998. In contrast, Kido and Sugiyama (2011) showed that all of the rugose coral genera present in the Gionyama Formation also occur in the Ningqiang Formation of South China, but they also demonstrate a number of genera in common with the Silurian of Tarim, North China and Australia.…”

Section: Summary Of the Kurosegawa Terranementioning

confidence: 99%

Ambiguous biogeographical patterns mask a more complete understanding of the Ordovician to Devonian evolution of Japan

Williams

Wallis

Oji³

et al. 2014

Island Arc

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Fossil assemblages of the Ordovician to Devonian successions of Japan suggest complex temporal, environmental and geographical controls on their biogeographical signature. Thus, limited similarity at the species-level between the trilobite, brachiopod and ostracod faunas of the South Kitakami, Hida-Gaien and Kurosegawa terranes in part reflects the sporadic stratigraphic distribution of shelly fauna within these terranes. As a result, and with the exception of corals and pan-tropical radiolarians, species-level similarities are greater with other regions of East

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“…In this paper we focus on six groups of Japanese trilobites that have recently undergone taxonomic revision, and which are interpreted to have a range of paleoecologies. Recent revision of the Illaenidae and Scutelluidae (Holloway & Lane, , , ) has demonstrated links between the trilobite faunas of Japan and Australia. It should be noted that the composition and delimitation of the families Illaenidae and Scutelluidae remain contentious, particularly so far as their effaced (illaenimorph) taxa are concerned (Holloway & Lane, , , ; Lane & Thomas, ; Whittington, ).…”

Section: Introductionmentioning

confidence: 99%

“…Recent revision of the Illaenidae and Scutelluidae (Holloway & Lane, , , ) has demonstrated links between the trilobite faunas of Japan and Australia. It should be noted that the composition and delimitation of the families Illaenidae and Scutelluidae remain contentious, particularly so far as their effaced (illaenimorph) taxa are concerned (Holloway & Lane, , , ; Lane & Thomas, ; Whittington, ). Of the taxa belonging to those families dealt with in this paper, Bumastella, Rhaxeros and Lalax are assigned to the Illaenidae and Japonoscutellum , Illaenoscutellum , Kosovopeltis and Borenoria to the Scutelluidae, following Holloway and Lane (, , ).…”

Section: Introductionmentioning

confidence: 99%

The paleobiogeographical significance of the Silurian and Devonian trilobites of Japan

et al. 2019

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Six major groups of trilobites from the Silurian and Devonian of Japan are evaluated for their paleobiogeographical signature. Silurian illaenids and scutelluids show four generic‐level and at least two species‐level links with the Australian segment of the Gondwana paleocontinent; encrinurids also indicate two generic‐level links with Australia and also the South China paleocontinent; whilst Devonian phacopids, and possibly proetids, suggest at least two generic‐level links with the North China paleocontinent. These different patterns may reflect the fragmentary biostratigraphical record of Japanese trilobites, but they also appear to reflect paleoenvironmental parameters associated with lithofacies, and paleoecology. Thus, Japanese assemblages of proetids and phacopids occurring in deep‐water clastic lithofacies have counterparts in similar settings in North China, and Japanese scutelluids and illaenids are strongly associated with shallow marine carbonate lithofacies that are similar to those of their occurrences in Australia. Japanese encrinurids occur in carbonate rocks indicative of shallow marine settings in the Kurosegawa Terrane, and they demonstrate a consistent paleobiogeographical affinity with Australia and South China. Larval ecology cannot be directly assessed for Japanese trilobite groups. However, proetids have consistently been shown to have planktonic protaspides, whereas illaenids, scutelluids, and encrinurids have benthic protaspides. Planktonic protaspides would have a greater propensity for distribution in ocean currents than benthic ones, and therefore may be of more limited paleobiogeographical utility. The combined data from the six different groups indicates that the complex paleobiogeographical patterns of the Japanese trilobite assemblages need to be interpreted with caution, and similarity of taxa does not necessarily denote paleogeographical proximity to other regions.

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Scutelluid trilobites from the Silurian of New South Wales

Abstract: Twenty-six species

Cited by 14 publications

References 35 publications

Coaptative devices, enrollment, and life habits in Paralejurus, a particular case in scutelluid trilobites

Coaptative devices, enrollment, and life habits in Paralejurus, a particular case in scutelluid trilobites

Ambiguous biogeographical patterns mask a more complete understanding of the Ordovician to Devonian evolution of Japan

The paleobiogeographical significance of the Silurian and Devonian trilobites of Japan

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