Maevarano Formation
Stratigraphic range: Maastrichtian
~70–66 Ma

PreЄ

Template:Period fossil range

Type| Geological formation
Sub-units| Masorobe, Anembalemba & Miadana Members
Underlies| Berivotra Formation
Overlies| Marovoay Beds
Thickness| >105 m (344 ft)
Lithology
Primary| Sandstone
Other| Claystone, siltstone
Location
Coordinates|  [ ⚑ ] : 15°54′S 46°36′E﻿ / ﻿15.9°S 46.6°E﻿ / -15.9; 46.6
Paleocoordinates|  [ ⚑ ] 30°06′S 38°24′E﻿ / ﻿30.1°S 38.4°E﻿ / -30.1; 38.4
Region| Mahajanga Province
Country| Madagascar
Extent| Mahajanga Basin
Type section
Named for| Maevarano River
Named by| Salètes
Year defined| 1895

Maevarano Formation (Madagascar)

The Maevarano Formation is a Late Cretaceous sedimentary rock formation found in the Mahajanga Province of northwestern Madagascar. It is most likely Maastrichtian in age,[1] and records a seasonal, semiarid environment with rivers that had greatly varying discharges. Notable animal fossils recovered include the theropod dinosaur Majungasaurus, the early bird Vorona, the paravian Rahonavis, the titanosaurian sauropod Rapetosaurus, and the giant frog Beelzebufo.

## Contents

* 1 Description
* 2 History of exploration
* 3 Paleoenvironment
* 4 Paleofauna
* 4.1 Invertebrates
* 4.2 Fish
* 4.2.1 Osteichthyes
* 4.3 Amphibians
* 4.4 Dinosaurs
* 4.4.1 Ornithischians
* 4.4.2 Sauropods
* 4.4.3 Theropods
* 4.5 Crocodylomorphs
* 4.6 Squamates
* 4.7 Turtles
* 4.8 Mammals
* 5 See also
* 6 References
* 6.1 Bibliography

## Description

The Maevarano Formation is well exposed in the Mahajanga Basin, in particular near the village of Berivotra near the northwestern coast of the island where its outcrops have been heavily dissected by erosion. At the time it was being deposited, its latitude was between 30°S and 25°S as Madagascar drifted northward after splitting from India about 88 million years ago. It is composed of three smaller units or members. The lowest is the Masorobe Member, which is usually reddish and is at least 80 metres (260 ft). Its rocks are mostly poorly sorted coarse-grained sandstones with some finer-grained beds. It is separated by an erosional disconformity from the next member, the Anembalemba Member. The lower portion of the Anembalemba Member is fine to coarse clay-rich sandstone, whitish or light grey in color, with cross-bedding. The upper portion of this member is made of poorly sorted clay-rich sandstone, light olive-grey in color, that lacks cross-bedding. Most vertebrate fossils come from the Anembalemba Member, especially from the upper portion. The Miadana Member, the third and uppermost member, is not always present, and is up to 25 metres (82 ft) in some places. Elsewhere, it is replaced by the marine Berivotra Formation. The Miadana Member is made up of claystone, siltstone, and sandstone, lacks cross-bedding, and has several colors of rock. The Maevarano Formation as a whole is underlain by the Marovoay beds and capped by the Berivotra Formation.[1]

The age of the Maevarano Formation has been debated; the Berivotra Formation, which is partially contemporaneous with the upper portions of the formation, shows that at least the upper part of the Maevarano is Maastrichtian in age. There is no evidence that it is Campanian,[1] despite previous reports to that effect.[2] The Berivotra Formation appears to include near its top a magnetic reversal, interpreted as the shift from Chron 30N to Chron 29R, which occurred approximately 65.8 million years ago (about 300,000 years before the Cretaceous–Paleogene boundary and associated Cretaceous–Paleogene extinction event. This suggests that Maevarano organisms also lived shortly before (geologically speaking) the extinction event.[1]

## History of exploration

The Maevarano Formation was first explored by French military physician Dr. Félix Salètes and his staff officer Landillon in 1895, and fossils and geologic data were sent to paleontologist Charles Depéret.[3] He briefly described the formation and named two dinosaurs from the remains (Titanosaurus madagascariensis and Megalosaurus crenatissimus, now Majungasaurus).[4] Similar collections were made throughout the 20th century, yielding mostly fragmentary fossils;[3] one such specimen, a rough partial skull roof, became the holotype of supposed pachycephalosaur (bonehead dinosaur) Majungatholus in 1979.[5] (This specimen was later shown to be part of the skull ornamentation of a Majungasaurus.) Large-scale expeditions (seven to date), under the banner of the Mahajanga Basin Project, began in 1993. These expeditions, conducted jointly by Stony Brook University and the University of Antananarivo, have greatly expanded knowledge of this formation and the organisms that lived while it was being deposited.[3]

## Paleoenvironment

The interpretation of Majungasaurus, Masiakasaurus and Rapetosaurus during the late Cretaceous

The Maevarano Formation is interpreted as a low-relief alluvial plain that over time was covered by a marine transgression. Broad, shallow rivers flowed to the northwest from central highlands; evidence for debris flows suggests that the discharges of the rivers varied greatly, with periods of dilute water flow, and periods of rapid erosion dumping sediment into the channels. Paleosols are reddish and include root casts. The paleosols and other sedimentologic evidence indicate well-drained floodplains with abundant vegetation adapted to a relatively dry climate, strongly seasonal (rainy and dry seasons) and at times semiarid (not unlike the present climate of the area).[1]

## Paleofauna

Animals found in the formation include frogs (including Beelzebufo ampinga),[6] turtles, snakes, lizards, at least seven species of crocodyliforms (including species of Mahajangasuchus and Miadanasuchus), abelisaurid theropod Majungasaurus, noasaurid Masiakasaurus, two types of titanosaurian sauropods (Rapetosaurus and Vahiny), and at least five species of bird-like dinosaurs, including Rahonavis. The 6 to 7 metres (20 to 23 ft) long Majungasaurus was likely the apex predator in the terrestrial environment. Crocodyliforms were very diverse and abundant.[1]

|  |

|
|

Color key
| Taxon | Reclassified taxon | Taxon falsely reported as present | Dubious taxon or junior synonym | Ichnotaxon | Ootaxon | Morphotaxon

|
|
|
|
|
|

| Notes
Uncertain or tentative taxa are in small text; ~~crossed out~~ taxa are discredited.

### Invertebrates

Invertebrates

Genus | Species | Location | Stratigraphic position | Material | Notes | Images
Cubiculum[7] | C. ornatus |  |  | Ovoid chambers in dinosaur bones  | A trace fossil, possibly puppal chambers of carrion beetles  |
Ethmosestheria[8] | E. mahajangaensis |  | Anembalemba Member  |  | A species of antronstheriid clam shrimp |
Osteocallis[7] | O. mandibulus |  |  | Curved grooves on dinosaur bones  | A trace fossil, possibly feeding marks by a similar insect as Cubiculum ornatus |

### Fish

#### Osteichthyes

Osteichthyes

Taxon | Species | Location | Stratigraphic position | Material | Notes | Images
Albula[9] | A. sp.  |  |  | Tooth plates and dentaries  | A species of bonefish  |
Characiformes indet.[9] |  |  |  | Partial jaw  |  |
Coelodus[9] | C. sp.  |  |  | A tooth plate  | A species of pycnodontid |
Cypriniformes?[9] |  |  |  |  |  |
Dipnoi indet.[10] |  |  | Masorobe and Anembalemba Members  | Burrows  |  |
Egertonia[9] | E. sp.  |  |  | Partial toothplates  |  |
Enchodus[9] | E. sp.  |  |  | Teeth  |  |
Lepisosteus[11] | L. sp.  |  |  | Scales, fin rays, teeth, vertebrae, skull bones  | A type of gar  |
Paralbula[9] | P. sp.  |  | Lac Kinkony Member  | Partial tooth plates  | A species of bonefish  |
Polypteridae indet.[12] |  |  | Anembalemba and Lac Kinkony members  | Skull bones, teeth, vertebrae, finlet spines, and scales  |  |
Sciaenidae indet.[9] |  |  |  |  | A species of croaker  |
Siluriformes indet.[9] |  |  |  | Vertebrae  | A type of catfish  |
Vango[13] | V. fahiny |  | Lac Kinkony Member  | Referred material is hyomandibulae, although other partial remains of gonorynchiform probably belongs to this taxa as well  | A chanid gonorynchiform, milkfish  |

### Amphibians

Amphibians

Genus | Species | Location | Stratigraphic position | Material | Notes | Images
Beelzebufo | Beelzebufo ampinga | locality MAD98-25[14] |  |  | A large frog |

### Dinosaurs

Indeterminate Lithostrotia remains formerly attributed to Titanosauridae. Undescribed Lithostrotia form. Indeterminate Enantiornithes remains. A rich avifauna with several undescribed taxa are known, including pengornithid enantiornithes and putative omnivoropterygids.[15]

#### Ornithischians

Ornithischians of the Maevarano Formation

Genus | Species | Location | Stratigraphic position | Material | Notes | Images
Stegosaurus[16] | S. madagascariensis[16] |  |  | "Teeth"[17] | An indeterminate thyreophoran.[18] |

#### Sauropods

Sauropods of the Maevarano Formation

Genus | Species | Location | Stratigraphic position | Material | Notes | Images
Rapetosaurus[19] | R. krausei[19] |  |  | "[Three] skulls, at least [one] postcranial skeleton."[19] | A titanosaur |
Titanosaurus[16] | T. madagascariensis[16] |  |  |  |  |
V. depereti[20] |  |  | "Partial braincase"[20] | A titanosaur |

#### Theropods

Theropods of the Maevarano Formation

Genus | Species | Location | Stratigraphic position | Material | Notes | Images
Falcatakely[21] | F. forsterae |  |  | "Partial skull"  | A member of Enantiornithes |
Majungasaurus[16] | M. crenatissimus[16] |  |  | "Scattered remains leading to nearly most of the animal."[22] | An abelisaur |
Masiakasaurus[16] | M. knopfleri[16] |  |  | "Disarticulated remains of at least 6 individuals," as well as other isolated fossils.[23] | A noasaurid abelisaur  |
Rahonavis[16] | R. ostromi[16] |  |  | "Partial postcranial skeleton"[24] | A paravian of unclear phylogenetic placement  |
Vorona[16] | V. berivotrensis[16] |  |  | "Partial hindlimbs"[25] | An ornithuromorph  |

### Crocodylomorphs

Crocodylomorphs

Genus | Species | Location | Stratigraphic position | Material | Notes | Images
Mahajangasuchus | M. insignis |  |  | disarticulated postcranial skeleton, multiple skull remains  | A mahajangasuchid  |
Miadanasuchus | M. oblita |  |  |  | A peirosaurid. Formerly known as Trematochampsa oblita |
Simosuchus | S. clarki |  |  | multiple specimens representing most of the skeleton  | A ziphosuchian |
Araripesuchus | A. tsangatsangana |  | Anembalemba Member  | multiple specimen including several skulls and one almost complete specimen  | A notosuchian |

### Squamates

Squamates

Genus | Species | Location | Stratigraphic position | Material | Notes | Images
Adinophis | A. fisaka |  |  |  | A madtsoiid snake |
Indophis | I. fanambinana |  |  |  | A nigerophid snake |
Kelyophis | K. hechti |  |  |  | A nigerophiid snake |
Konkasaurus | K. mahalana |  |  |  | A cordylid lizard  |
Madtsoia | M. madagascariensis |  |  |  | A madtsoiid snake |
Menarana | M. nosymena |  |  | Vertebrae and rib fragments  | A madtsoiid snake |

### Turtles

Turtles

Genus | Species | Location | Stratigraphic position | Material | Notes | Images
Kinkonychelys | K. rogersi |  |  |  | A side-necked turtle |
Sahonachelys | S. mailakavava |  |  |  | A sahonachelyid side-necked turtle  |
Sokatra | S. antitra |  |  |  | A sahonachelyid side-necked turtle  |

### Mammals

Mammal remains include an undescribed gondwanathere,[26] a broken tooth UA 8699, which has been interpreted both as metatherian and as eutherian, a non-gondwanathere multituberculate tooth fragment, a non-gondwanathere multituberculate femur,[27] and a yet undescribed mammal known from an articulated skeleton.[28] Some taxa are particularly large sized herbivores, exemplifying the diversity of Mesozoic mammals.[29]

Mammals

Genus | Species | Location | Stratigraphic position | Material | Notes | Images
Adalatherium | A. hui |  |  | A nearly-complete skeleton  | A gondwanatherian |
Lavanify | L. miolaka |  |  | Multiple teeth and dentition  | A gondwanatherian |
Vintana | V. sertichi |  |  |  | A gondwanatherian |

## See also

* Lists of fossiliferous stratigraphic units in Africa
* List of fossiliferous stratigraphic units in Madagascar
* Geology of Madagascar

## References

1. ↑ 1.0 1.1 1.2 1.3 1.4 1.5 Rogers et al., 2007
2. ↑ Weishampel et al., 2004
3. ↑ 3.0 3.1 3.2 Krause et al., 2007b
4. ↑ Depéret, 1896
5. ↑ Sues & Taquet, 1979
6. ↑ Evans, Susan E.; Jones, Marc E. H.; Krause, David W. (2008). "A giant frog with South American affinities from the Late Cretaceous of Madagascar". Proceedings of the National Academy of Sciences of the United States of America 105 (8): 2951–2956. doi:10.1073/pnas.0707599105. PMID 18287076. Bibcode: 2008PNAS..105.2951E.
7. ↑ 7.0 7.1 Roberts, E.M.; Rogers, R.R.; Foreman, B.Z. (2007). "Continental insect borings in dinosaur bone: Examples from the late Cretaceous of Madagascar and Utah". Journal of Paleontology 81 (1): 201–208. doi:10.1666/0022-3360(2007)81[201:CIBIDB2.0.CO;2].
8. ↑ Stigall, A.L.; Hartman, J.H. (2008). "A New Spinicaudatan Genus (Crustacea: 'Conchostraca') from the Late Cretaceous of Madagascar". Palaeontology 51 (5): 1053–1067. doi:10.1111/j.1475-4983.2008.00799.x. Bibcode: 2008Palgy..51.1053S.
9. ↑ 9.0 9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 Ostrowski, S.A. (2012). "The teleost ichthyofauna from the Late Cretaceous of Madagascar: systematics, distributions, and implications for Gondwanan biogeography". Michigan State University. Geological Sciences. https://d.lib.msu.edu/etd/1842/datastream/OBJ/download/The_teleost_ichthyofauna_from_the_Late_Cretaceous_of_Madagascar___systematics__distributions__and_implications_for_Gondwanan_biogeography.pdf. Retrieved 2022-01-28.
10. ↑ Marshall, M.S.; Rogers, R.R. (2013). "Lungfish Burrows from the Upper Cretaceous Maevarano Formation, Mahajanga Basin, Northwestern Madagascar". PALAIOS 27 (12): 857–866. doi:10.2110/palo.2012.p12-018r. Bibcode: 2013Palai..27..857M.
11. ↑ Gottfried, M.D.; Krause, D.W. (1998). "First record of gars (Lepisosteidae, Actinopterygii) on Madagascar: Late Cretaceous remains from the Mahajanga Basin.". Journal of Vertebrate Paleontology 18 (2): 275–279. doi:10.1080/02724634.1998.10011056. Bibcode: 1998JVPal..18..275G.
12. ↑ Murray, Alison M.; Brinkman, Donald B.; Gottfried, Michael D.; Krause, David W. (11 March 2026). "Late Cretaceous bichirs from Madagascar provide the first documentation of Polypteriformes (Actinopterygii, Cladistia) in Eastern Gondwana". Cretaceous Research. doi:10.1016/j.cretres.2026.106370.
13. ↑ Murray, Alison M.; Brinkman, Donald B.; Friedman, Matt; Krause, David W. (2023-10-17). "A large, freshwater chanid fish (Ostariophysi: Gonorynchiformes) from the Upper Cretaceous of Madagascar". Journal of Vertebrate Paleontology. doi:10.1080/02724634.2023.2255630. ISSN 0272-4634.
14. ↑ Evans et al., 2014, p.5
15. ↑ O'Connor and Forster, 2010. A Late Cretaceous (Maastrichtian) avifauna from the Maevarano Formation, Madagascar. Journal of Vertebrate Paleontology. 30(4), 1178-1201.
16. ↑ 16.00 16.01 16.02 16.03 16.04 16.05 16.06 16.07 16.08 16.09 16.10 16.11 "83.2 Faritany Majunga, Madagascar; 3. Maevarano Formation," in Weishampel et al., 2004, p.605
17. ↑ "Table 14.1," in Weishampel, et al. (2004). Page 326.
18. ↑ Maidment, Susannah; Norman, David; Barrett, Paul; Upchurch, Paul (2008). "Systematics and phylogeny of Stegosauria (Dinosauria: Ornithischia)". Journal of Systematic Palaeontology 6 (4): 367–407. doi:10.1017/S1477201908002459. Bibcode: 2008JSPal...6..367M.
19. ↑ 19.0 19.1 19.2 Curry Rogers, Kristina; Forster, Catherine A. (2 August 2001). "The last of the dinosaur titans: a new sauropod from Madagascar". Nature 412 (6846): 530–534. doi:10.1038/35087566.
20. ↑ 20.0 20.1 Cite error: Invalid `<ref>` tag; no text was provided for refs named `Vahiny`
21. ↑ Patrick M. O'Connor; Alan H. Turner; Joseph R. Groenke; Ryan N. Felice; Raymond R. Rogers; David W. Krause; Lydia J. Rahantarisoa (2020). "Late Cretaceous bird from Madagascar reveals unique development of beaks". Nature 588 (7837): 272–276. doi:10.1038/s41586-020-2945-x. PMID 33239782. Bibcode: 2020Natur.588..272O.
22. ↑ "Table 3.1," in Weishampel et al., 2004, p.50
23. ↑ "Table 3.1," in Weishampel et al., 2004, p.49
24. ↑ "Table 11.1," in Weishampel et al., 2004, p.211
25. ↑ "Table 11.1," in Weishampel et al., 2004, p.212
26. ↑ Krause et al, 2014
27. ↑ Krause, David W.; Hoffmann, Simone; Werning, Sarah (December 2017). "First postcranial remains of Multituberculata (Allotheria, Mammalia) from Gondwana". Cretaceous Research 80: 91–100. doi:10.1016/j.cretres.2017.08.009. Bibcode: 2017CrRes..80...91K.
28. ↑ Krause, David W.; O'Connor, Patrick M.; Rogers, Kristina Curry; Sampson, Scott D.; Buckley, Gregory A.; Rogers, Raymond R. (23 August 2006). "Late Cretaceous terrestrial vertebrates from Madagascar: Implications for Latin American biogeography". Annals of the Missouri Botanical Garden 93 (2): 178–208. doi:10.3417/0026-6493(2006)93[178:LCTVFM2.0.CO;2]. https://www.biodiversitylibrary.org/part/390696.
29. ↑ Krause et al., 2020

### Bibliography

* Depéret, Charles (1896), "Note sur les Dinosauriens Sauropodes et Théropodes du Crétacé supérieur de Madagascar" (in French), Bulletin de la Société Géologique de France 21: 176–194
* Evans, Susan E.; Groenke, Joseph R.; Jones, Marc E. H.; Turner, Alan H.; Krause, David W.; Claessens, Leon (2014), "New Material of Beelzebufo, a Hyperossified Frog (Amphibia: Anura) from the Late Cretaceous of Madagascar", PLoS ONE 9 (1), doi:10.1371/journal.pone.0087236, PMID 24489877, Bibcode: 2014PLoSO...987236E Bibcode: 2014PLoSO...987236E
* Krause, David W.; Hoffmann, Simone; Hu, Yaoming; Wible, John R.; Rougier, Guillermo W.; Kirk, E. Christopher; Groenke, Joseph R.; Rogers, Raymond R. et al. (2020), "Skeleton of a Cretaceous mammal from Madagascar reflects long-term insularity", Nature 581 (7809): 1–7, doi:10.1038/s41586-020-2234-8, PMID 32461642, Bibcode: 2020Natur.581..421K
* Krause, David W.; Hoffmann, Simone; Wible, John R.; Kirk, E. Christopher; Schultz, Julia A.; von Koenigswald, Wighart; Groenke, Joseph R.; Rossie, James B. et al. (2014), "First cranial remains of a gondwanatherianmammal reveal remarkable mosaicism", Nature 525
* Krause, David W.; Sampson, Scott D.; Carrano, Matthew T.; O'Connor, Patrick M. (2007b), "Overview of the history of discovery, taxonomy, phylogeny, and biogeography of Majungasaurus crenatissimus (Theropoda: Abelisauridae) from the Late Cretaceous of Madagascar", Journal of Vertebrate Paleontology 27 (sup2): 1–20, doi:10.1671/0272-4634(2007)27[1:OOTHOD2.0.CO;2]
* Rogers, K.C.; Wilson, J.A. (2014), "Vahiny depereti, gen. et sp. nov., a new titanosaur (Dinosauria, Sauropoda) from the Upper Cretaceous Maevarano Formation, Madagascar", Journal of Vertebrate Paleontology 34 (3): 606, doi:10.1080/02724634.2013.822874, Bibcode: 2014JVPal..34..606R, https://www.researchgate.net/publication/262070167, retrieved 2020-05-04
* Rogers, Raymond R.; Krause, David W.; Rogers, Kristina Curry; Rasoamiaramanana, Armand H.; Rahantarisoa, Lydia (2007), "Paleoenvironment and Paleoecology of Majungasaurus crenatissimus (Theropoda: Abelisauridae) from the Late Cretaceous of Madagascar", Journal of Vertebrate Paleontology 27 (sup2): 21–31, doi:10.1671/0272-4634(2007)27[21:PAPOMC2.0.CO;2]
* Sues, Hans-Dieter; Taquet, Phillipe (1979), "A pachycephalosaurid dinosaur from Madagascar and a Laurasia−Gondwanaland connection in the Cretaceous", Nature 279 (5714): 633–635, doi:10.1038/279633a0, Bibcode: 1979Natur.279..633S Bibcode: 1979Natur.279..633S
* Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (2004), The Dinosauria, 2nd edition, Berkeley: University of California Press, pp. 1–880, ISBN 0-520-24209-2, https://books.google.com/books?id=vtZFDb_iw40C, retrieved 2019-02-21

0.00

(0 votes)

Original source: https://en.wikipedia.org/wiki/Maevarano Formation. Read more

|

Retrieved from "https://handwiki.org/wiki/index.php?title=Earth:Maevarano_Formation&oldid=4573912"