Non-parvipelians (i.e., most Triassic ichthyosaurs) rarely have avascular necrosis, if equivocal cases are not considered. Parvipelvians (predominantly post-Triassic ichthyosaurs) manifest variable frequency of decompression syndrome (bends). One interpretation of the ichthyosaur data is that the habit of repetitive diving in ichthyosaurs did not evolve until parvipelvians appeared. The latter are equipped with the true tailbend and a semi-symmetrical caudal fin. This increases the efficiency of continuous swimming, probably a requirement for repetitive diving. Stenopterygius, a typical tuna-shaped ichthyosaur, is an exception, in that no bends have been identified in specimens examined to date. It is possible that the genus solely had a physiological adaptation to avoid bends, as do modern whales.

Fossil – Ichthyosaurs proved susceptible to bends, based on examination of proximal femoral and humeral subsidence. Examination of the stylopodials of 13 ichthyopterygian genera reveals a large intergeneric variation in frequencies of avascular necrosis. A general phylogenetic trend:

Non-parvipelians (i.e., most Triassic ichthyosaurs) rarely have avascular necrosis, if equivocal cases are not considered. Parvipelvians (predominantly post-Triassic ichthyosaurs) manifest variable frequency of decompression syndrome (bends). One interpretation of the ichthyosaur data is that the habit of repetitive diving in ichthyosaurs did not evolve until parvipelvians appeared. The latter are equipped with the true tailbend and a semi-symmetrical caudal fin. This increases the efficiency of continuous swimming, probably a requirement for repetitive diving. Stenopterygius, a typical tuna-shaped ichthyosaur, is an exception, in that no bends have been identified in specimens examined to date. It is possible that the genus solely had a physiological adaptation to avoid bends, as do modern whales.

Mudge BF. 1876. Notes on the Tertiary and Cretaceous Period of Kansas. Bulletin of the Survey (U.S. Geological and Geographical Survey of the Territories) ii(3):211–221.

Trauma – Healed rib fractures in saurians.

Bite marks in saurian bones from Galeocerdo shark.

Fractured saurian vertebrae which have fused and become confluent.

Fossil – Healed rib fractures in saurians.

Bite marks in saurian bones from Galeocerdo shark.

Fractured saurian vertebrae which have fused and become confluent.

Mudge BF. 1878. Geology of Kansas. In First Biennial Report of the Kansas State Board of Agriculture: pp. 60–63. Topeka, KS: Kansas State Board of Agriculture.

Trauma – Plesiosaur with five fractured spinous fractures, coalesced in healing.

Serrated Galeocerdo shark tooth marks on Cretaceous bones of a possible plesiosaur.

Fossil – Plesiosaur with five fractured spinous fractures, coalesced in healing.

Serrated Galeocerdo shark tooth marks on Cretaceous bones of a possible plesiosaur.

Mufti SA. 1969. Tail regeneration in an adult salamander, Desmognathus fuscus. American Zoologist 9:613.

Trauma – Time course of tail regeneration in Desmognathus fuscus and Triturus viridescens.

Mufti SA. 1973. Tail regeneration following amputation in adult Triturus viridescens. Pakistani Journal of Zoology 5:31–49.

Trauma – No autotomy, but regeneration takes place in Triturus viridescens.

Mufti SA, Simpson SB. 1972. Tail regeneration following autotomy in the adult salamander, Desmognathus fuscus. Journal of Morphology 136:297–312.

Trauma – Tail regeneration in Desmognathus fuscus.

Muggiasca F, Gandolla E. 1976. I Rettili del Ticino. Descrizione delle singole specie e considerazioni generali [The reptiles of Ticino. Descriptions of single species and general considerations]. 78pp.; Canobbio-Lugano: Aurora S.A [Italian].

Congenital – Dicephalic Natrix helvetica embryo (fig. 25).

Muir JH. 1990. Three anatomically aberrant albino Crotalus atrox neonates. Bulletin Chicago Herpetological Society 25(3):41–42.

Congenital – Dicephalic and two western diamondback rattlesnakes Crotalus with fused mouths, attributed to abnormal cool period.

Cites dicephalic Crotalus adamanteus (Klauber 1972; Murphy and Shadduck 1978), Crotalus durissus terrificus, Crotalus viridis oreganus, Crotalus b. basiliscus, Crotalus horridus, Crotalus v. viridis (Klauber 1972) and Crotalus horridus (Lasher 1980).

Mulder EWA. 2001. Co-ossified vertebrae of mosasaurs and cetaceans: Implications for the mode of locomotion of extinct marine reptiles. Paleobiology 27:724–734.

Infection – Mosasaurus camperi MNHNP AC 9649–9775/9776 with 6 fused caudal vertebrae with spongiform bone (Dollo 1882).

Vertebral – cites Martin and Bell’s 1995 report of club-tailed Clidastes. Dollos’s

(1882) fused pygal vertebrae in Plioplatecarpus marshi were actually abnormal. Dollo also referred to this specimen as Mosasaurus camperi which had two areas of fused caudal vertebrae. This MNHNP AC 9649-

9775/9776 specimen is said to closely resemble IRSNB 1496F and 1496HH, also described by Dollo.

Fossil – Mosasaurus camperi MNHNP AC 9649–9775/9776 with 6 fused caudal vertebrae with spongiform bone (Dollo 1882).

Cites Martin and Bell’s 1995 report of club-tailed Clidastes. Dollos’s (1882) fused pygal vertebrae in Plioplatecarpus marshi were actually abnormal. Dollo also referred to this specimen as Mosasaurus camperi which had two areas of fused caudal vertebrae. This MNHNP AC 9649-9775/9776 specimen is said to closely resemble IRSNB 1496F and 1496HH, also described by Dollo.

Mulder EWA. 2003. Co-ossified vertebrae of mosasaurs and cetceans: Implications for the mode of locomotion of extinct marine reptiles. In Mulder WW. On latest Cretaceous tetrapods from the Masstrichtian type area. Doctoral Thesis, Universiteit Amsterdam: 149–159.

Infection – Co-ossified vertebrae in Plioplatecarpus marshi MNHNP AC 9649- 9775/9776 were clearly infected, as were MND 20.01.842 and MND 20.01.826. Fused, infected vertebrae in Mosasaurus camperi.

Vertebral – Co-ossified vertebrae and “club-tailed” mosasaurs described. Co-ossified infected vertebrae in Plioplatecarpus marshi. Those in IRScNB 1 496 and 1497 reveal smooth fusion, predominantly ligamentous.

Fossil – Co-ossified vertebrae in Plioplatecarpus marshi MNHNP AC 9649- 9775/9776 were clearly infected, as were MND 20.01.842 and MND 20.01.826. Fused, infected vertebrae in Mosasaurus camperi.

Co-ossified vertebrae and “club-tailed” mosasaurs described. Co-ossified infected vertebrae in Plioplate­carpus marshi. Those in IRScNB 1 496 and 1497 reveal smooth fusion, predominantly ligamentous.

Müller H. 1852. Eine Eidechse, Lacerta viridis, mit zwei über einander gelagerten Schwänzen, welche beide als das Produkt einer überreichen und durch den feinern Bau der wiedererzeugten bemerkenswerthen Reproductionskraft erscheinen. [A lizard, Lacerta viridis, with two tails lying above each other]. Verhandlungen der physikalisch-medicinischen Gesellschaft in Würzburg 2 [German].

Trauma – Lacerta viridis specimen with divided tail (upper and lower tail without vertebrae, only cartilaginous axis = regenerations).

Müller H. 1864. Ueber die Regeneration der Wirbelsäule und des Rückenmarks bei Eidechsen und Tritonen. [On the regeneration of the vertebral colume and of the nerul cord of lizards and tritons]. Gratulationsschrift der physikalisch-medizinischen Gesellschaft in Würzburg zu der Jubelfeier der Senckenberg’schen Stiftung, Frankfurt a. M.: 62–64 [German].

Trauma – Discussion of the structure of the new formed part of double tail of Lacerta viridis, which he described in 1852.

Müller E. 1996. Ueber die Abstossung und Regeneration des Eidechsenschwanzes. [About the rejection and regeneration of the lizard tail]. Jahreshefte des Vereins für vaterländische Naturkunde in Württemberg Stuttgart 52: LXXXV–LXXXVII (not 85–87) [German].

Trauma – Mentions tail loss in lizards.

Muneoka K, Bryant S. 1984. Regeneration and Development of vertebrae appendages. Symposium of the Zoological Society of London In: The Structure, Development and Evolution of Reptiles: A Festschrift in Honour of Professor A. d’A. Bellairs on the occasion of his retirement, WJ Ferguson, ed. London: Academic Press, 52:177–196.

Congenital – Surgical implantation produces supernumerary limbs in Ambystoma mexicanum.

Munyer EA. 1963. Syndactylism in the lizard Sceloporus undulatus hyacinthinus. Bulletin of the Philadelphia Herpetological Society 11:28.

Congenital – Syndactylism in northern fence lizard Sceloporus undulatus hyacinthinus and southern prairie lizard Sceloporus undulatus consorbrinus (Loewen 1941).

Murphy TD. 1965. High incidence of two parasitic infestations and two morphological abnormalities in a population of the frog, Rana palustris Le Conte. American Midland Naturalist 74:233–239.

Trauma – Faulty forelimb eruption as small limb in 1.2% of Rana palustris, attributed to bite by larva of Hannemania dunni.

Murphy JB, Shadduck JA. 1978. Reproduction in the eastern diamondback rattlesnake, Crotalus adamantus in captivity, with comments regarding a teratoid birth anomaly. British Journal of Herpetology 5:727–733.

Congenital – Derodymous Crotalus adamantus.

Muto Y. 1969a. Anomalies in the hindlimb skeletons of toad larvae reared at a high temperature. Congenital Anomalies 9:61–73.

Environmental – Bubo vulgaris formosus at 30°C produces hindlimb abnormalities including reduction in size and fusion of tarsals and metatarsals and hyperphalangism.

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Related posts:

1. Bibliography H-L
2. Bibliography D-G
3. Frequently Cited in Discussion of Amphibian and/or Reptile Pathology but which do not Discuss Actual Amphibian or Reptile Abnormalities
4. List of Fossil Taxa

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