Cope's Rule and Romer's theory: patterns of diversity and gigantism in eurypterids and Palaeozoic vertebrates

Lamsdell, James C.; Braddy, Simon J.

doi:10.1098/rsbl.2009.0700

Cited by 72 publications

(95 citation statements)

References 18 publications

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“…They have been interpreted as apex predators in shallow water near shore basins [3][4][5]. A study of the chelicera of the pterygotid Acutiramus cummingsi (Pterygotidae), however, concluded that it could at best 'trap, grasp and slice soft-bodied and relatively weak prey' [6].…”

Section: Introductionmentioning

confidence: 99%

What big eyes you have: the ecological role of giant pterygotid eurypterids

et al. 2014

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Eurypterids are a group of extinct chelicerates that ranged for over 200 Myr from the Ordovician to the Permian. Gigantism is common in the group; about 50% of families include taxa over 0.8 m in length. Among these were the pterygotids (Pterygotidae), which reached lengths of over 2 m and were the largest arthropods that ever lived. They have been interpreted as highly mobile visual predators on the basis of their large size, enlarged, robust chelicerae and forward-facing compound eyes. Here, we test this interpretation by reconstructing the visual capability of Acutiramus cummingsi (Pterygotidae) and comparing it with that of the smaller Eurypterus sp. (Eurypteridae), which lacked enlarged chelicerae, and other arthropods of similar geologic age. In A. cummingsi, there is no area of lenses differentiated to provide increased visual acuity, and the interommatidial angles (IOA) do not fall within the range of high-level modern arthropod predators. Our results show that the visual acuity of A. cummingsi is poor compared with that of co-occurring Eurypterus sp. The ecological role of pterygotids may have been as predators on thin-shelled and soft-bodied prey, perhaps in low-light conditions or at night.

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Section: Introductionmentioning

confidence: 99%

What big eyes you have: the ecological role of giant pterygotid eurypterids

et al. 2014

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“…The second group includes the mid-sized (,1 m long [2,15]) S. acuminata and Erettopterus species, as well as Eurypterus remipes. The chelicerae of S. acuminata are small with no denticles, similar to the typical eurypterid grasping appendages in E. remipes [16].…”

Section: Resultsmentioning

confidence: 99%

“…The first group includes the large (up to 2.5 m long [1,2]) Jaekelopterus and Pterygotus species, and a specimen representing a new genus and species, IVPP-14593. Both J. rhenaniae and P. anglicus have high visual acuity as indicated by low IOA and a large number of lenses (figure 2 and table 1).…”

Section: Resultsmentioning

confidence: 99%

All the better to see you with: eyes and claws reveal the evolution of divergent ecological roles in giant pterygotid eurypterids

et al. 2015

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Pterygotid eurypterids have traditionally been interpreted as active, high-level, visual predators; however, recent studies of the visual system and cheliceral morphology of the pterygotid Acutiramus contradict this interpretation. Here, we report similar analyses of the pterygotids Erettopterus, Jaekelopterus and Pterygotus, and the pterygotid sister taxon Slimonia. Representative species of all these genera have more acute vision than A. cummingsi. The visual systems of Jaekelopterus rhenaniae and Pterygotus anglicus are comparable to that of modern predatory arthropods. All species of Jaekelopterus and Pterygotus have robust crushing chelicerae, morphologically distinct from the weaker slicing chelicerae of Acutiramus. Vision in Erettopterus osiliensis and Slimonia acuminata is more acute than in Acutiramus cummingsi, but not to the same degree as in modern active predators, and the morphology of the chelicerae in these genera suggests a grasping function. The pterygotids evolved with a shift in ecology from generalized feeder to specialized predator. Pterygotid eurypterids share a characteristic morphology but, although some were top predators, their ecology differs radically between genera.

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“…Eurypterids form a prominent component of Silurian faunas in the peri-Gondwanan Prague Basin and, together with cephalopods, are the largest known animals of the Silurian (Lamsdell & Braddy 2010). The oldest eurypterids previously described from the Prague Basin originate from the Ludlow cephalopod limestones, and the acme of the group starts in the lowermost Přídolí but they remain common until the upper Lochkovian.…”

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confidence: 99%

“…Pterygotids have also been recorded from other peri-Gondwanan basins such as Catalonia, Iberia (Chlupáč et al 1997) and Sardinia (Gnoli 1992, Corradini et al 2009). Increasing abundance of eurypterids throughout the Silurian is a feature shared between the periGondwanan and perhaps even the global marine faunas (Lamsdell & Braddy 2010).…”

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confidence: 99%

Silurian carcinosomatid eurypterids from the Prague Basin (Czech Republic)

Budil¹,

Manda²,

Tetlie³

2014

Bull. Geosci.

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The eurypterid record from the Prague Basin includes occasional Ludlow faunas, but in the uppermost Silurian (Přídolí) eurypterids suddenly become common in relatively deep water facies. Pterygotids clearly dominate these late Silurian faunas, whereas carcinosomatids are represented by the single species Eusarcana acrocephala, known from only a few specimens. This species is revised and its validity is discussed herein. A new eurypterid fauna found in deep water shale facies is described from the lower and middle part of the Motol Formation, Wenlock, Sheinwoodian-Homerian, Cyrtograptus murchisoni to C. lundgreni graptolite biozones, at Praha-Lochkov. It consists of common fragments of the carcinosomatid eurypterid described here as Eusarcana? sp. A and rare possible pterygotid fragments. This is the earliest evidence of carcinosomatids outside Laurentia and one of the earliest records of the group worldwide. This early occurrence outside a hypothetical Laurentian evolutionary centre is discussed with respect to the palaeobiogeography of other faunas colonising peri-Gondwanan basins after the decline of widespread early Silurian anoxia. A previous suggestion that carcinosomatids (presumed basal members of the Carcinosomatoidea) had similar distribution patterns to pterygotoids is discussed. Eurypterids migrated into the peri-Gondwanan realm from the tropical zone, but the dispersion potential of carcinosomatids into the temperate and cool water realm was probably lower than that of pterygotids. In the Prague Basin, the carcinosomatid-dominated fauna of the Wenlock age was replaced in the late Silurian by a pterygotid-dominated fauna.•

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Cope's Rule and Romer's theory: patterns of diversity and gigantism in eurypterids and Palaeozoic vertebrates

Cited by 72 publications

References 18 publications

What big eyes you have: the ecological role of giant pterygotid eurypterids

What big eyes you have: the ecological role of giant pterygotid eurypterids

All the better to see you with: eyes and claws reveal the evolution of divergent ecological roles in giant pterygotid eurypterids

Silurian carcinosomatid eurypterids from the Prague Basin (Czech Republic)

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