The earliest known stem-tetrapod from the Lower Devonian of China

Lü, Jing; Zhu, Min; Long, John A.; Zhao, Wei; Senden, Tim J.; Jia, Liantao; Qiao, Tuo

doi:10.1038/ncomms2170

Cited by 65 publications

(76 citation statements)

References 18 publications

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“…This contrasts with Youngolepis , Powichthys and porolepiforms -considered in the next section- which are assigned to the most basal part of the dipnoan stem group in the majority of recent analyses [28], [55] but are not so obviously lungfish-like. The ‘fossil lungfish’ are all undisputed members of the stem group [22], [55], [56] and are always recovered crownward to Youngolepis , Powichthys and porolepiforms.…”

Section: Discussionmentioning

confidence: 82%

The First Virtual Cranial Endocast of a Lungfish (Sarcopterygii: Dipnoi)

Clement

Ahlberg

2014

PLoS ONE

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Lungfish, or dipnoans, have a history spanning over 400 million years and are the closest living sister taxon to the tetrapods. Most Devonian lungfish had heavily ossified endoskeletons, whereas most Mesozoic and Cenozoic lungfish had largely cartilaginous endoskeletons and are usually known only from isolated tooth plates or disarticulated bone fragments. There is thus a substantial temporal and evolutionary gap in our understanding of lungfish endoskeletal morphology, between the diverse and highly variable Devonian forms on the one hand and the three extant genera on the other. Here we present a virtual cranial endocast of Rhinodipterus kimberleyensis, from the Late Devonian Gogo Formation of Australia, one of the most derived fossil dipnoans with a well-ossified braincase. This endocast, generated from a Computed Microtomography (µCT) scan of the skull, is the first virtual endocast of any lungfish published, and only the third fossil dipnoan endocast to be illustrated in its entirety. Key features include long olfactory canals, a telencephalic cavity with a moderate degree of ventral expansion, large suparaotic cavities, and moderately enlarged utricular recesses. It has numerous similarities to the endocasts of Chirodipterus wildungensis and Griphognathus whitei, and to a lesser degree to 'Chirodipterus' australis and Dipnorhynchus sussmilchi. Among extant lungfish, it consistently resembles Neoceratodus more closely than Lepidosiren and Protopterus. Several trends in the evolution of the brains and labyrinth regions in dipnoans, such as the expansions of the utricular recess and telencephalic regions over time, are identified and discussed.

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Section: Discussionmentioning

confidence: 82%

The First Virtual Cranial Endocast of a Lungfish (Sarcopterygii: Dipnoi)

Clement

Ahlberg

2014

PLoS ONE

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“…The Devonian record of South China, combining the oldest fossil appearances of key groups and containing the most phylogenetically basal fossil taxa have established this region as a possible center of origin for several crown-group sarcopterygian lineages, including anatomically modern coelacanths [59], lungfishes [60] and tetrapodomorphs [61–63]. The discovery of diversified stem-sarcopterygians in the Silurian of South China reveals a rich regional history of osteichthyans extending as far back as the early Ludlow, indicative of an as yet largely unknown chapter in early gnathostome evolution well before the advent of the Devonian “Age of Fishes”.…”

Section: Discussionmentioning

confidence: 99%

A new osteichthyan from the late Silurian of Yunnan, China

Choo

Zhu

et al. 2017

PLoS ONE

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Our understanding of early gnathostome evolution has been hampered by a generally scant fossil record beyond the Devonian. Recent discoveries from the late Silurian Xiaoxiang Fauna of Yunnan, China, have yielded significant new information, including the earliest articulated osteichthyan fossils from the Ludlow-aged Kuanti Formation. Here we describe the partial postcranium of a new primitive bony fish from the Kuanti Formation that represents the second known taxon of pre-Devonian osteichthyan revealing articulated remains. The new form, Sparalepis tingi gen. et sp. nov., displays similarities with Guiyu and Psarolepis, including a spine-bearing pectoral girdle and a placoderm-like dermal pelvic girdle, a structure only recently identified in early osteichthyans. The squamation with particularly thick rhombic scales shares an overall morphological similarity to that of Psarolepis. However, the anterior flank scales of Sparalepis possess an unusual interlocking system of ventral bulges embraced by dorsal concavities on the outer surfaces. A phylogenetic analysis resolves Sparalepis within a previously recovered cluster of stem-sarcopterygians including Guiyu, Psarolepis and Achoania. The high diversity of osteichthyans from the Ludlow of Yunnan strongly contrasts with other Silurian vertebrate assemblages, suggesting that the South China block may have been an early center of diversification for early gnathostomes, well before the advent of the Devonian “Age of Fishes”.

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“…3 shows the absolute and relative socket sizes for our dataset grouped according to the adaptive zones identified by the analysis of selective regime shifts. We refer to the group before the increase in eye socket size as "finned tetrapods" (6). As shown in Fig.…”

Section: Significancementioning

confidence: 95%

Massive increase in visual range preceded the origin of terrestrial vertebrates

MacIver

Schmitz

Mugan

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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The evolution of terrestrial vertebrates, starting around 385 million years ago, is an iconic moment in evolution that brings to mind images of fish transforming into four-legged animals. Here, we show that this radical change in body shape was preceded by an equally dramatic change in sensory abilities akin to transitioning from seeing over short distances in a dense fog to seeing over long distances on a clear day. Measurements of eye sockets and simulations of their evolution show that eyes nearly tripled in size just before vertebrates began living on land. Computational simulations of these animal's visual ecology show that for viewing objects through water, the increase in eye size provided a negligible increase in performance. However, when viewing objects through air, the increase in eye size provided a large increase in performance. The jump in eye size was, therefore, unlikely to have arisen for seeing through water and instead points to an unexpected hybrid of seeing through air while still primarily inhabiting water. Our results and several anatomical innovations arising at the same time suggest lifestyle similarity to crocodiles. The consequent combination of the increase in eye size and vision through air would have conferred a 1 million-fold increase in the amount of space within which objects could be seen. The "buena vista" hypothesis that our data suggest is that seeing opportunities from afar played a role in the subsequent evolution of fully terrestrial limbs as well as the emergence of elaborated action sequences through planning circuits in the nervous system. fish-tetrapod transition | vision | visual ecology | terrestriality | prospective cognition B efore terrestrial vertebrates arose, their ancestors inhabited underwater environments, where vision is highly compromised compared with vision above water. The visual difference between life in water and life above it is comparable with driving fast on a foggy road, where our responses must be rapid and simple, vs. driving in clear daylight conditions, where deliberation over more complex choices is enabled by the vast increase in sensory range. Nonetheless, although an immense quantity of work has been done on the emergence of limbs during the evolution of land vertebrates, how visual capability changed during the transition from water to land has not been explored. In part, this lack of exploration is because computational visual ecology-necessary to interpret the fossil data-has not been combined with early tetrapod paleontology. Through combining these disciplines, here we probe the evolutionary history of the switch in our visual sensory ecology from water to air. Surprisingly, our results show that eyes tripled in size just before full-time life on land evolved. Convergent lines of evidence, including our own, strongly support the hypothesis that a crocodilian ecotype-using the greatly enhanced visual capabilities conferred by vision through air to prey on the bounty of unexploited invertebrates that long preceded the vertebrates onto ...

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The earliest known stem-tetrapod from the Lower Devonian of China

Cited by 65 publications

References 18 publications

The First Virtual Cranial Endocast of a Lungfish (Sarcopterygii: Dipnoi)

The First Virtual Cranial Endocast of a Lungfish (Sarcopterygii: Dipnoi)

A new osteichthyan from the late Silurian of Yunnan, China

Massive increase in visual range preceded the origin of terrestrial vertebrates

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