New osteichthyans (bony fishes) from the Devonian of Central Australia

Abstract. Osteichthyan remains described from two localities in Central Australia (Mount Winter, Amadeus Basin, and southern Toomba Range, Georgina Basin) include the dipnoan Amadeodipterus kencampbelli n. gen., n. sp., the osteolepidid Muranjilepis winterensis n. gen., n. sp., and the onychodontid Luckeus abudda n. gen., n. sp., as well as indeterminate holoptychiid scales, osteolepidid scales of a new type from the Georgina Basin locality, and indeterminate onychodontid remains from both localities. Amadeodipterus n. gen. is a short-headed dipterid dipnoan with bones A and H enclosed into the skull roof; Muranjilepis n. gen. is a small form with short postparietal and parietoethmoidal shields, large orbits, and large pores of the sensory line system. It is closest to Thursius, and some Chinese osteolepidid material. Luckeus n. gen. is based on an onychodontid lower jaw with Meckel’s cartilage separately ossified perichondrally from the dentary and infradentary, and carrying the parasymphysial tooth whorl. Different osteichthyan taxa at the two localities indicate a difference in age and/or palaeoenvironment within the Early-Middle Devonian. Knochenfischreste aus zwei Fundorten Zentralaustraliens (Mount Winter, Amadeus Becken und südlicher Toomba Rücken, Georgina Becken) umfassen den Lungenfisch Amadeodipterus kencampbelli n. gen., n. sp., den osteolepididen Sarcopterygier Muranjilepiswinterensis n. gen., n. sp., und den onychodontiden Sarcopterygier Luckeus abudda n. gen., n. sp., sowie unbestimmte holoptychiide und osteolepidide Schuppen eines neuen Typs aus dem Fundort im Georgina Becken und unbestimmte onychodontide Reste von beiden Fundorten. Amadeodipterus n. gen. ist ein kurz-schädeliger Lungenfisch, bei dem die Knochen A und H in das Schädeldach miteingeschlossen sind. Bei Muranjilepis n. gen. handelt es sich um einen kleinen Osteolepididen mit kurzem Postparietal- und Parietoethmoidal-Schild, großen Augenhöhlen und großen Poren des Sinneskanalsystems; er ist am nächsten mit Thursius und einigen chinesischen Osteolepididen verwandt. Ein unbestimmter onychodontider Unterkiefer zeigt ein wahrscheinlich primitives Merkmal in der perichondralen Verknöcherung des Meckelschen Knorpels getrennt von Dentale und Infradentale, der die Unterlage der parasymphysialen Zahnspirale bildet. Verschiedene Knochenfischtaxa treten an den beiden Lokalitäten auf; das deutet auf unterschiedliches Alter und/oder Palaeoenviroment an der Unter-Mitteldevongrenze zwischen beiden Lokalitäten hin. doi:10.1002/mmng.200410002

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Memoirs: The Posterior End of Meckel's Cartilage and Related Ossifications in Bony Fishes

Journal of Cell Science ◽

10.1242/jcs.s2-80.317.1 ◽

1937 ◽

Vol s2-80 (317) ◽

pp. 1-38

Author(s):

R. WHEELER HAINES

Keyword(s):

Joint Surface ◽

Connective Tissues ◽

Endochondral Bone ◽

Meckel's Cartilage ◽

Articular Process ◽

Meckel’S Cartilage ◽

Bony Fishes ◽

Growth Zones ◽

Special Growth ◽

And Cartilage

1. In modern Dipnoi (Protopterus) the membrane bones are separated by connective tissue from Meekel's cartilage, and there is no endochondral or perichondral bone. The cartilage grows evenly over its whole extent. 2. In Polypterus a large articular ossifies the posterior end of the cartilage, including the retro-articular process, and spreads into the neighbouring connective tissues. 3. In Elops the joint surface is carried partly by the articular, and partly by the retro-articular, a special ossification of the retro-articular process. 4. In most teleosts (Mugil, Sardina, Trigla) the articular is absent and the angular invades the perichondrium and cartilage to form the joint surface. Special growth zones of flattened cells are formed in the cartilage which by their growth carry the retro-articular, angular, and dentary away from one another, stability of the jaw being maintained by new growth of the membranous parts of the bones. 5. Endochondral bone is reduced or absent in some specialized fishes (Tetrodon, Notopogon). 6. The sesamoid articular of teleosts is a separated part of the angular which gives insertion to the adductor mandibulae muscle. 7. An attempt is made to follow the evolution of Meckel's cartilage and the related ossifications by a comparison of the early Dipnoi, Crossopterygii, and Amphibia described in the literature with modern forms.

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Diverse stem-chondrichthyan oral structures and evidence for an independently acquired acanthodid dentition

Royal Society Open Science ◽

10.1098/rsos.210822 ◽

2021 ◽

Vol 8 (11) ◽

Author(s):

Richard P. Dearden ◽

Sam Giles

Keyword(s):

Conveyor Belt ◽

Major Obstacle ◽

Site Specific ◽

Meckel's Cartilage ◽

Jaw Bones ◽

Lateral Edge ◽

Meckel’S Cartilage ◽

Independent Origin ◽

Bony Fishes ◽

Dermal Bone

The teeth of sharks famously form a series of transversely organized files with a conveyor-belt replacement that are borne directly on the jaw cartilages, in contrast to the dermal plate-borne dentition of bony fishes that undergoes site-specific replacement. A major obstacle in understanding how this system evolved is the poorly understood relationships of the earliest chondrichthyans and the profusion of morphologically and terminologically diverse bones, cartilages, splints and whorls that they possess. Here, we use tomographic methods to investigate mandibular structures in several early branching ‘acanthodian’-grade stem-chondrichthyans. We show that the dentigerous jaw bones of disparate genera of ischnacanthids are united by a common construction, being growing bones with non-shedding dentition. Mandibular splints, which support the ventro-lateral edge of the Meckel's cartilage in some taxa, are formed from dermal bone and may be an acanthodid synapomorphy. We demonstrate that the teeth of Acanthodopsis are borne directly on the mandibular cartilage and that this taxon is deeply nested within an edentulous radiation, representing an unexpected independent origin of teeth. Many or even all of the range of unusual oral structures may be apomorphic, but they should nonetheless be considered when building hypotheses of tooth and jaw evolution, both in chondrichthyans and more broadly.

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Modulated Expression of Type X Collagen in the Meckel's Cartilage with Different Developmental Fates

Developmental Biology ◽

10.1006/dbio.1995.1224 ◽

1995 ◽

Vol 170 (2) ◽

pp. 387-396 ◽

Cited By ~ 39

Author(s):

Kun Sung Chung ◽

Howard H. Park ◽

Kang Ting ◽

Hiroko Takita ◽

Suneel S. Apte ◽

...

Keyword(s):

Type X Collagen ◽

Meckel's Cartilage ◽

Meckel’S Cartilage

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The localization of thiamine pyrophosphatase activity in Meckel's cartilage cells during endochondral ossification

Histochemistry ◽

10.1007/bf00489908 ◽

1982 ◽

Vol 76 (4) ◽

pp. 539-546 ◽

Cited By ~ 2

Author(s):

T. Akisaka

Keyword(s):

Endochondral Ossification ◽

Meckel's Cartilage ◽

Meckel’S Cartilage ◽

Thiamine Pyrophosphatase ◽

Cartilage Cells ◽

Pyrophosphatase Activity

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Palate and braincase ofWhatcheeria deltaeLombard & Bolt, 1995

Earth and Environmental Science Transactions of the Royal Society of Edinburgh ◽

10.1017/s1755691018000774 ◽

2018 ◽

Vol 109 (1-2) ◽

pp. 177-200 ◽

Cited By ~ 1

Author(s):

John R. BOLT ◽

R. Eric LOMBARD

Keyword(s):

Horizontal Plane ◽

Unique Feature ◽

Sister Taxon ◽

Dental Occlusion ◽

Posterior View ◽

Maximum Width ◽

Palatal Shelf ◽

Meckel’S Cartilage ◽

Lower Jaw ◽

Early Tetrapods

ABSTRACTThe reconstructed palate ofWhatcheeria deltaeindicates a skull that was unusually narrow: at least 2.2 times longer than wide if the pterygoids are conservatively placed in the horizontal plane. This maximum width is narrower than any other early tetrapod reconstructed so far. Rotating the pterygoids to produce a vaulted palate would produce an even narrower skull. Primitive palatal features include very narrow interpterygoid vacuities and a vomer, palatine, and ectopterygoid with fang-sized replacement pairs. It is derived in that there is no anterior palatal fenestra and the premaxilla has a substantial palatal shelf – a combination of characters shared only with Proterogyrinus among early tetrapods. There is a possible septomaxilla in one specimen.Whatcheeriadiffers from and is more derived thanPederpes, its likely sister taxon, in that only the pterygoid is covered with denticles, the vomer, palatine, and ectopterygoid containing labyrinthine teeth only. Reconstructed dental occlusion indicates that the large choana apparently accommodated the large dentary fangs; this would be a unique feature among early tetrapods. The palatal ramus of the pterygoid is longer than the quadrate ramus, which does not have a descending flange. Like Meckel's cartilage in the lower jaw, the palatoquadrate is fully ossified in larger specimens, such that in a posterior view of the skull the pterygoid is mostly hidden from sight by the epipterygoid. The ossified neurocranium consists of the basiparasphenoid and basioccipital; no ossified sphenethmoid has been found. Remains of otic capsules are partial, crushed, and smeared, so no useful morphology is available. The stapes appears to be more columnar and less plate-like than in many other primitive, early tetrapods.

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Functional analysis of CTRP3/cartducin in Meckel’s cartilage and developing condylar cartilage in the fetal mouse mandible

Journal of Anatomy ◽

10.1111/j.1469-7580.2011.01354.x ◽

2011 ◽

Vol 218 (5) ◽

pp. 517-533 ◽

Cited By ~ 17

Author(s):

Tamaki Yokohama-Tamaki ◽

Takashi Maeda ◽

Tetsuya S. Tanaka ◽

Shunichi Shibata

Keyword(s):

Functional Analysis ◽

Condylar Cartilage ◽

Meckel's Cartilage ◽

Fetal Mouse ◽

Meckel’S Cartilage

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Effect of Biomechanical Environment on Degeneration of Meckel’s Cartilage

Journal of Dental Research ◽

10.1177/0022034520960118 ◽

2020 ◽

pp. 002203452096011

Author(s):

M. Farahat ◽

G.A.S. Kazi ◽

E.S. Hara ◽

T. Matsumoto

Keyword(s):

Endochondral Ossification ◽

Biomechanical Properties ◽

Cartilage Degradation ◽

Middle Region ◽

Meckel's Cartilage ◽

3 Dimensional ◽

Meckel’S Cartilage ◽

Surrounding Environment ◽

Rigid Environment

During orofacial tissue development, the anterior and posterior regions of the Meckel’s cartilage undergo mineralization, while the middle region undergoes degeneration. Despite the interesting and particular phenomena, the mechanisms that regulate the different fates of Meckel’s cartilage, including the effects of biomechanical cues, are still unclear. Therefore, the purpose of this study was to systematically investigate the course of Meckel’s cartilage during embryonic development from a biomechanical perspective. Histomorphological and biomechanical (stiffness) changes in the Meckel’s cartilage were analyzed from embryonic day 12 to postnatal day 0. The results revealed remarkable changes in the morphology and size of chondrocytes, as well as the occurrence of chondrocyte burst in the vicinity of the mineralization site, an often-seen phenomenon preceding endochondral ossification. To understand the effect of biomechanical cues on Meckel’s cartilage fate, a mechanically tuned 3-dimensional hydrogel culture system was used. At the anterior region, a moderately soft environment (10-kPa hydrogel) promoted chondrocyte burst and ossification. On the contrary, at the middle region, a more rigid environment (40-kPa hydrogel) enhanced cartilage degradation by inducing a higher expression of MMP-1 and MMP-13. These results indicate that differences in the biomechanical properties of the surrounding environment are essential factors that distinctly guide the mineralization and degradation of Meckel’s cartilage and would be valuable tools for modulating in vitro cartilage and bone tissue engineering.

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