Armored articulated animals

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Armored articulated animals
Glyptodon and nine-banded armadillo

Glyptodon and nine-banded armadillo

Temporal occurrence
Paleocene to date
55 to 0 million years
Locations

America

Systematics
Amniotes (Amniota)
Synapsids (Synapsida)
Mammals (mammalia)
Higher mammals (Eutheria)
Sub-articulated animals (Xenarthra)
Armored articulated animals
Scientific name
Cingulata
Illiger , 1811

The armored joint animals (Cingulata) form an order of the joint animals (Xenarthra). The only representatives living today are the armadillos (Dasypoda) with the two families of the Dasypodidae and the Chlamyphoridae . In addition to the armadillos, a number of other groups are also counted among the armored articulated animals. The distribution area covers almost all of South America and the southern parts of North America . As a special feature of the group, an outer bony armor has developed, which consists of individual bone platelets ( osteoderms ) and covers both the head, the back and, in most species, the tail. The now generally recognized scientific name Cingulata was coined in 1811.

features

As the name suggests, the armored articulated animals are the only known representatives of the mammals to have a bony skin armor. In contrast to the pangolin scales , the bony armor of the armored collateral animals consists of individual osteoderms , small bony plates that are arranged in rows. As a rule, a head shield, a back armor and with a few exceptions also a tail armor can be distinguished. The stomach and legs are only sparsely covered with bone platelets. The back armor usually consists of a shoulder and a pelvic shield. The armor of the armored articulated animals appears to be relatively diverse, several basic principles can be distinguished:

  • a rigid back armor in which the shoulder and pelvic shields are not arranged to be movable to one another, for example in the Glyptodontidae ;
  • the shoulder and pelvic shields are slightly pushed one over the other in the middle of the body, so that the entire armor of the back is only limited mobility , as is the case with the Pachyarmatheriidae ;
  • a movable back armor in which a different number of transverse movable bands are formed between the shoulder and pelvic shields; the type occurs with the armadillos , the Peltephilidae and the Pampatheriidae ; the following types can be distinguished here:
  • the armor of the back consists only of movable ligaments ( Peltephilidae and some early armadillos);
  • the back armor consists in its entire front part (shoulder shield) of movable ligaments (some early armadillos);
  • the back armor consists of a rigid shoulder and pelvic shield with flexible straps in between (armadillos and pampatheria);

The individual bone platelets have a different shape depending on the species and are each decorated in a characteristic manner on their surface. In cross-section, the osteoderms consist of an upper and a lower bone layer, between which there is a softer layer provided with cavities. Various glands and hair follicles are embedded in these . Both in their external and internal structure, the bone platelets are important for the determination of fossil and recent forms and thus have a taxonomic value.

The bone armor is already put on in the embryonic stage , but the osteoderms have not yet grown together, but are connected by soft tissue. Only after the birth does the armor harden, which is partly due to the narrowness of the birth canal. The formation of the shell leads to some anatomical peculiarities. Among other things, the armadillos have an extraordinarily long penis in relation to their body size . This is necessary to bridge the large distance to the female sex organ, which is created by the rigid back armor during sexual intercourse . In addition, its erectile tissue is extremely stable as a result of collagen fibers running longitudinally and transversely and thus withstands lateral shear forces when erect. Another consequence arises from the largely missing fur covering, which is why the armor has a high thermal conductivity. In connection with a poorly developed insulating layer of fat and a low metabolism , this leads to a strong loss of heat. The armadillos are therefore able to survive in extremely dry and hot areas. At the same time, however, this also limits their spread in cooler climates.

Other features include the formation of xenarthric joints on the posterior thoracic and lumbar vertebrae, which is a general feature of the secondary articular animals. In some lines such as the Glyptodontidae, however, the mark has been lost again due to the high degree of intergrowth of the spine. The bit is characterized by a homodontic structure. The individual teeth are mostly narrow or flap-like like a pin. The number of teeth is highly variable, including the recent giant armadillo ( Priodontes ) with up to 100 teeth, the highest number among terrestrial mammals.

Systematics

Internal systematics of secondary articulated animals according to Gibb et al. 2015
 Xenarthra 
  Pilosa 
  Folivora 

 Bradypodidae


   

 Choloepodidae



  Vermilingua 

 Cyclopedidae


   

 Myrmecophagidae




  Cingulata 

 Dasypodidae


   

 Chlamyphoridae




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The armored joint animals are an order within the superordinate order of the joint animals (Xenarthra), one of the four main lines of the higher mammals (Eutheria). The closest relatives of the armored articulated animals are the tooth arms (pilosa), which include the sloths (Folivora) and anteaters (Vermilingua). The common feature of the secondary articular animals is the eponymous xenarthric joints on the lateral processes of the posterior thoracic and lumbar vertebrae. In addition, the secondary articular animals of other higher mammals soften due to peculiarities in their teeth. In general, the front teeth are missing, and most forms have no tooth enamel . According to molecular genetic studies, the secondary animals separated from the other higher mammals as early as the lower Cretaceous , about 103 million years ago. The armored articulated animals and the tooth arms differentiated themselves at the beginning of the Paleocene about 65 million years ago. The armored Newben's articulated animals were first found in fossil records in the Upper Paleocene, around 58 million years ago.

The only two families of this order still alive today are the Dasypodidae and the Chlamyphoridae from the group of armadillos (Dasypoda). A number of extinct lines are also included. The Glyptodontidae are of importance , which appeared from the Eocene to the Pleistocene and, especially in their late development phase, produced sometimes huge forms with a body weight of up to 2 tons. Its main feature is found in the rigid back armor. The Pampatheriidae , whose temporal distribution ranges from the Miocene to the Pleistocene , are classified as closely related to the Glyptodonts . With a maximum body weight of around 200 kg, these were significantly smaller, but larger than the armadillos. In terms of the structure of their teeth, they showed similarities to the glyptodonts. The armor, in turn, was comparable to that of the armadillos, as there were movable bands between a rigid shoulder and pelvic shield, the number of which, unlike the large variation in armadillos, was always three. The close relationship of the Glyptodonts and the Pampatherien is expressed by the superordinate taxon of the Glyptodonta . The Palaeopeltidae , whose back armor is reminiscent of the armadillos, but the skull of the glyptodons, are also systematically close . However, too little is known about this group, which occurs largely only in the Eocene and Oligocene with the genus Palaeopeltis . Another line of development are the Pachyarmatheriidae , which occurred from the Upper Miocene to the beginning of the Holocene in both North and South America. Characteristic of their relatives is a back armor, the shoulder and pelvis parts of which overlap without any movable ligaments in between. The Pachyarmatheriidae are regarded as a sister group to the Glyptodonta. The Peltephilidae, in turn, are characterized by two steeply erected scale horns on the snout and a back armor, which possibly only consisted of movable ligaments. Their main distribution time falls into the Oligocene and Miocene. The Protobradidae are problematic , to which with Protobradys only one genus from the Paleogene of Patagonia belongs. Described on the basis of a single jaw fragment at the beginning of the 20th century, the holotype of the form has meanwhile been lost, so that no more precise statements can be made.

Overall, the order is composed as follows:

  • Order Cingulata Illiger , 1811

Research history

Naming

The scientific name Cingulata comes from Johann Karl Wilhelm Illiger from the year 1811. Illiger originally only included the armadillos, other representatives of the armored articulated animals were hardly known at the time. The name refers to the armor of the animals. It is of Latin origin and is derived from cingulum ("belt"), which means something like "belted". The sloths and anteaters are in turn summarized in the pilosa, which comes from the Latin word pilus for "hair" and can be translated as "hairy". Accordingly, the main groups of secondary articulated animals were distinguished by the earlier researchers according to their characteristic body cover. The name Pilosa was established by William Henry Flower in 1883.

A synonym often used, especially in the 19th and early 20th centuries, is Loricata, which was introduced by Félix Vicq d'Azyr in 1792 (as Loricati) to unite the armadillos. Later, in 1842, Richard Owen first used the term in a grammatically correct form. It was not until 1910 that Theodore Gill pointed out that Loricata was preoccupied, since Blasius Merrem had used the term for crocodiles in 1820 . He therefore suggested Illiger's Cingulata as an alternative. However, this only prevailed with George Gaylord Simpson's work on the general taxonomy of mammals in 1945.

Systematic history

Relationship of armored articulated animals according to morphological data from Billet et al. 2011
 Cingulata 

 Peltephilidae


 Dasypoda 

 Dasypodidae


  Chlamyphoridae 

 Tolypeutinae


   

 Chlamyphorinae


  Euphractinae 


 Eutatini


  Glyptodonta 

 Pampatheriidae


   

 Glyptodontidae




   

 Euphractini







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There have been various attempts to systematically structure the armored articulated animals . Many scientists preferred to split the group in two. So also Simpson 1945, who differentiated the group into the two superfamilies the Dasypoidea for the armadillos and the Glyptodontoidea for the Glyptodonts . The Dasypoidea he also added the Pampatherien as a subfamily (called Chlamytheriinae) and the Peltephilidae as a separate family, while he added Palaeopeltis to the Glyptodontoidea with an uncertain position. A similar system was favored again and again in the further course of the 20th century, but sometimes with a varying composition. Bryan Patterson and Rosendo Pascual were an exception here , who at the end of the 1960s and beginning of the 1970s also endured the Palaeopeltidae as a separate line alongside these two large groups . George F. Engelmann then introduced cladistic methods for the first time at the end of the 1970s for structuring armored articulated animals. The division of the group into two was retained in his scheme. However, he differentiated these with the Dasypoda and the Glyptodonta on a higher taxonomic level, whereby the Glyptodonta also contained the Pampatherien and the Eutatini in addition to the actual Glyptodonts , the latter represent extinct armadillos from the further relationship of the six-banded armadillo , the bristle armadillo and the dwarf armadillo . Engelmann saw the close relationship of the three groups confirmed by the formation of a solid core of osteodentin in the rear teeth. Engelmann's structure was largely ignored in the following period, instead Patterson returned to the old structure in 1988 together with William D. Turnbull and Walter Segall and referred the Peltephilidae and the Pampatheriidae back to the armadillo family. Malcolm C. McKenna and Susan K. Bell only partially supported this classification in their 1997 Classification of mammals above the species level , as they brought the pampatheria closer to the glyptodon.

In one of the most extensive phylogenetic studies of armored collateral animals to date, Timothy J. Gaudin and John R. Wible considered the recent and numerous fossil armadillos plus some representatives of the Glyptodontidae, Pampatheriidae and Peltephilidae. In this investigation, which was largely based on skull features, the two authors confirmed on the one hand the close relationship between the glyptodonts and pampatheria, while at the same time they saw both groups in a line of development of the armadillos. As the closest relationship they worked out the euphractine armadillos. As a result of their work, Gaudin and Wible practically eliminated the idea of ​​a dichotomy of armored articulated animals that had existed since the beginning . Refined investigations and additional fossil material then led in 2011 a research group led by Guillaume Billet to move both the Pampatherien and the Glyptodont deeper into the armadillos, as their studies suggested a closer relationship to the Eutatini. This made the armadillos as a group paraphyletic .

Relationship of armored articulated animals according to molecular genetic data from Delsuc et al. 2016
 Cingulata 

 Dasypodidae


  Chlamyphoridae 

 Euphractinae


   

 Glyptodontidae (Glyptodontinae?)


   

 Chlamyphorinae


   

 Tolypeutinae






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With the transition from the 20th to the 21st century, molecular genetic and biochemical methods of investigation increasingly gained influence on the systematics, as was the case with armored articulated animals. Initially limited to the current forms of the armadillos, genetic data of Doedicurus as a Pleistocene member of the Glyptodontidae could be obtained for the first time in 2016 . After this, the picture of a deep embedding of the glyptodons in the armadillos was confirmed. Unlike it indicated the skeleton anatomical results, but were here closer ties with the tolypeutinen ( armadillos , giant armadillo and cabassous ) and the chlamyphorinen (Gürtelmulle) armadillos, as its sister group , the Glyptodonten turned out, while the euphractinen species were further out. As a result, the assumed basic two-fold structure of the armored armadillos could no longer be maintained. Rather, the armadillos were subsequently divided into two families, the Dasypodidae with the long-nosed armadillos and the Chlamyphoridae with all other species. The glyptodonts form part of the Chlamyphoridae, but it is currently unclear whether they are on the status of family or subfamily. In the former case, the Chlamyphoridae would form a paraphyletic group. As a result, the glyptodons are a side branch of the armadillos and not a parallel development, as initially thought.

From a genetic point of view, the status of the pampatheria, which also occurred in the Upper Pleistocene, is unclear, as no genetic material has yet been extracted from them. The same applies to the Pachyarmatheriidae , which have been proven until the early Holocene. Their character form Pachyarmatherium was only defined in 1995 on the basis of individual bone platelets, but was mostly considered to be closer to the armadillos. Finds of complete armor in 2018 revealed a structure that was clearly different from other armored articulated animals, so that Juan C. Fernicola and colleagues introduced the Pachyarmatheriidae as an independent family, which has a sister group position to the Glyptodons and Pampatherias. The Palaeopeltidae, Peltephilidae and Protobradidae largely disappeared much earlier, at least for the Peltephilidae, due to anatomical features, a very basal position within the armored articulated animals is usually assumed.

literature

  • TS Kemp: The Origin & Evolution of Mammals. Oxford University Press, Oxford 2005. ISBN 0-198-50761-5

Individual evidence

  1. ↑ a b c d Juan C. Fernicola, Andrés Rinderknecht, Washington Jones, Sergio F. Vizcaíno and Kleberson Porpino: A new species of Neoglyptatelus (Mammalia, Xenarthra, Cingulata) from the late Miocene of Uruguay provides new insights on the evolution of the dorsal armor in cingulates. Ameghiniana 55, 2018, pp. 233-252
  2. ^ Robert V. Hill: Comparative Anatomy and Histology of Xenarthran Osteoderms. Journal of Morphology 267, 2006, pp. 1441-1460
  3. ↑ CM Krmpotic, MR Ciancio, C. Barbeito, RC Mario and AA Carlini: Osteoderm morphology in recent and fossil euphractine xenarthrans. Acta Zoologica 90, 2009, pp. 339-351
  4. ↑ CM Krmpotic, MR Ciancio, AA Carlini, MC Castro, AC Scarano and CG Barbeito: Comparative histology and ontogenetic change in the carapace of armadillos (Mammalia: Dasypodidae). Zoomorphology 134, 2015, pp. 601-616
  5. ^ Diane A. Kelly: Axial orthogonal fiber reinforcement in the penis of the nine-banded armadillo (Dasypus novemcinctus). Journal of Morphology 233, 1997, pp. 249-255
  6. ^ GJ Tattersall and V. Cadena: Insights into animal temperature adaptations revealed through thermal imaging. Imaging Science Journal 58, 2010, pp. 261-268
  7. ↑ Mariella Superina and Loughry WJ: Life on the Half Shell: Consequences of a carapace in the Evolution of Armadillos (Xenarthra: Cingulata). Journal of Mammalian Evolution 19, 2012, pp. 217-224
  8. ↑ H. Gregory McDonald: Xenarthran skeletal anatomy: primitive or derived? Senckenbergiana biologica 83, 2003, pp. 5-17
  9. ↑ Sergio F. Vizcaíno: The teeth of the “toothless”: novelties and key innovations in the evolution of xenarthrans (Mammalia, Xenarthra): Paleobiology 35 (3), 2009, pp. 343-366
  10. ↑ a b Gillian C. Gibb, Fabien L. Condamine, Melanie Kuch, Jacob Enk, Nadia Moraes-Barros, Mariella Superina, Hendrik N. Poinar and Frédéric Delsuc: Shotgun Mitogenomics Provides a Reference Phylogenetic Framework and Timescale for Living Xenarthrans. Molecular Biology and Evolution 33 (3), 2015, pp. 621-642
  11. ↑ Édison Vicente Oliveira and Lílian Paglarelli Bergqvist: A new Paleogene armadillo (Mammalia, Dasypodoidea) from the Itaboraí basin, Brazil. Associatión Paleontológica Argentina, Publicatión Especial 5, 1998, pp. 35-40
  12. ↑ a b c Timothy J. Gaudin and John R. Wible: The Phylogeny of Living and Extinct Armadillos (Mammalia, Xenarthra, Cingulata): A Craniodental Analysis. In: MT Carrano, TJ Gaudin, RW Blob and JR Wible (eds.): Amniote Paleobiology. Chicago / London: University of Chicago Press, 2006, pp. 153-198
  13. ↑ Kenneth D. Rose: The beginning of the age of mammals. Johns Hopkins University Press, Baltimore, 2006, pp. 1–431 (pp. 200–204)
  14. ↑ Daniel Perera, Pablo Martín and Torino Ciancio: La Presencia del Xenartro Palaeopeltis inornatus Ameghino, 1894, en la Formación Fray Bentos (Oligoceno Tardío), Uruguay. Ameghiniana 51 (3), 2014, pp. 254-258
  15. ↑ Laureano R. González-Ruiz, Gustavo J. Scillato-Yané, Cecilia M. Krmpotic and Alfredo A. Carlini: A new species of Peltephilidae (Mammalia: Xenarthra: Cingulata) from the late Miocene (Chasicoan SALMA) of Argentina. Zootaxa 3359, 2012, pp. 55-64
  16. ↑ Laureano R. González-Ruiz, Martín R. Cianco and Flávio Gois: El especimen mas completo de Peltephilidae Ameghino (Mammalia, Xenarthra, Cingulata): aportes sistematicos. Ameghiniana 50 (6, suppl.), 2013, p. R52
  17. ^ George Gaylord Simpson: The beginning of the age of mammals in South America. Part 1. Introduction. Systematics: Marsupialia, Edentata, Condylarthra, Litopterna and Notioprogonia. Bulletin of the American Museum of Natural History 91, 1948, pp. 1–232 (p. 71)
  18. ↑ a b Malcolm C. McKenna and Susan K. Bell: Classification of mammals above the species level. Columbia University Press, New York, 1997, pp. 1-631 (pp. 82-91)
  19. ↑ a b c Frédéric Delsuc, Gillian C. Gibb, Melanie Kuch, Guillaume Billet, Lionel Hautier, John Southon, Jean-Marie Rouillard, Juan Carlos Fernicola, Sergio F. Vizcaíno, Ross DE MacPhee and Hendrik N. Poinar: The phylogenetic affinities of the extinct glyptodonts. Current Biology 26, 2016, pp. R155-R156, doi: 10.1016 / j.cub.2016.01.039
  20. ^ Johann Karl Wilhelm Illiger: Prodromus systematis mammalium et avium additis terminis zoographicis utriudque classis. Berlin, 1811, pp. 1–301 (p. 110) ( [1] )
  21. ↑ In it A. Croft and Velizar Simeonovski: Horned armadillos and rafting monkeys. The fascinating fossil mammals of South America. Indiana University Press, 2016, pp. 1–304 (pp. 13–14)
  22. ↑ Vicq d'Azyr: Système anatomique des Quadrupédes. Encyclopédie méthodique. Paris, 1792, pp. 1–632 (pp. Ciii) ( [2] )
  23. ^ Richard Owen: Description of the skeleton of an extinct gigantic Sloth, Mylodon robustus, Owen, with observations on the osteology, natural affinities, and probable habitats of the Megatherioid quadrupeds in general. London, 1842, pp. 1–176 (especially p. 167) ( [3] )
  24. ↑ Blasius Merrem: Attempting a system of amphibians. Tentamen systematis Amphibiorum. Marburg, 1820, pp. 1–191 (pp. 7, 34) ( [4] )
  25. ^ Theodore Gill: Classification of the edentates. Science 32 (81), 1919, p. 56
  26. ^ A b George Gaylord Simpson: The Principles of Classification and a Classification of Mammals. Bulletin of the American Museum of Natural History 85, 1945, pp. 1–350 (pp. 193–194)
  27. ↑ a b c Guillaume Billet, Lionel Hautier, Christian de Muizon and Xavier Valentin: Oldest cingulate skulls provide congruence between morphological and molecular scenarios of armadillo evolution. Proceedings of the Royal Society B, 278, 2011, pp. 2791-2797
  28. ^ A b Bryan Patterson, William D. Turnbull and Walter Segall: The Ear Region in Xenarthrans (= Edentata: Mammalia) Part I. Cingulates. Fieldiana Geology 18, 1988, pp. 1-46
  29. ↑ Frédéric Delsuc, Francois M. Catzeflis, Michael J. Stanhope and Emmanuel JP Douzery: The evolution of armadillos, anteaters and sloths depicted by nuclear and mitochondrial phylogenies: implications for the status of the enigmatic fossil Eurotamandua. Proceedings of the Royal Society of London B 268, 2001, pp. 1605-1615
  30. ↑ Frédéric Delsuc, Michael J. Stanhope and Emmanuel JP Douzery: Molecular systematics of armadillos (Xenarthra, Dasypodidae): contribution of maximum likelihood and Bayesian analyzes of mitochondrial and nuclear genes. Molecular Phylogenetics and Evolution 28, 2003, pp. 261-275
  31. ↑ Frédéric Delsuc, Sergio F. Vizcaíno and Emmanuel JP Douzery: Influence of Tertiary paleoenvironmental changes on the diversification of South American mammals: a relaxed molecular clock study within xenarthrans. BMC Evolutionary Biology 4 (11), 2004, pp. 1-13
  32. ↑ Maren Möller-Krull, Frédéric Delsuc, Gennady Churakov, Claudia Marker, Mariella Superina, Jürgen Brosius, Emmanuel JP Douzery and Jürgen Schmitz: Retroposed Elements and Their Flanking Regions Resolve the Evolutionary History of Xenarthran Mammals (Armadillos, Anteaters and Sloths). Molecular Biology and Evolution 24, 2007, pp. 2573-2582
  33. ↑ Frederic Delsuc, Mariella Superina, Marie-Ka Tilak, Emmanuel JP Douzery and Alexandre Hassanin: Molecular phylogenetics unveils the ancient evolutionary origins of the enigmatic fairy armadillos. Molecular Phylogenetics and Evolution 62, 2012, 673-680
  34. Jump up ↑ Kieren J. Mitchell, Agustin Scanferla, Esteban Soibelzon, Ricardo Bonini, Javier Ochoa and Alan Cooper: Ancient DNA from the extinct South American giant glyptodont Doedicurus sp. (Xenarthra: Glyptodontidae) reveals that glyptodonts evolved from Eocene armadillos. Molecular Ecology 25 (14), 2016, pp. 3499-3508, doi: 10.1111 / mec.13695
  35. ↑ Kevin F. Downing and Richard S. White: The cingulates (Xenarthra) of the Leisey Shell Pit local fauna (Irvingtonian), Hillsborough County, Florida. Bulletin of Florida Museum of Natural History 37, 1995, pp. 375-396

Web links

Commons : Cingulata  - collection of images, videos and audio files