Galula Formation

Galula Formation
Stratigraphic range: Aptian-Campanian ~120–75  Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Unit of	Red Sandstone Group
Sub-units	Mtuka Member, Namba Member
Underlies	Unconformity with Nsungwe Formation
Overlies	Unconformity with Karoo Supergroup or basement
Thickness	600–3,000 m (2,000–9,800 ft)
Lithology
Primary	Sandstone
Other	Conglomerate, mudstone
Location
Coordinates	7°06′S31°12′E / 7.1°S 31.2°E / -7.1; 31.2
Approximate paleocoordinates	28°48′S16°30′E / 28.8°S 16.5°E / -28.8; 16.5
Region	Rukwa Region, Songwe Region
Country	Tanzania
Extent	African Great Lakes, Rukwa Rift Basin
Type section
Named for	Galula
Named by	Roberts et al.
Location	Galula Coalfields
Year defined	2010
Coordinates	8°40′55.6″S32°53′33.5″E / 8.682111°S 32.892639°E / -8.682111; 32.892639
Thickness at type section	520 m (1,710 ft)
Galula Formation (Tanzania)

The Galula Formation is a geological formation located south of Lake Rukwa in Tanzania, part of the Red Sandstone Group of the Rukwa Rift Basin. Along with the unconformably overlying Oligocene Nsungwe Formation. It is divided into two members, the lower Mtuka Member and the upper Namba Member. ^[1]

The age of the deposit is poorly constrained, with the Mtuka Member likely being Aptian to Cenomanian in age, while the Namba Member being Cenomanian to Campanian in age based on Geomagnetic reversals. ^[2] It is correlated with the Dinosaur Beds of Malawi.

The formation is fossiliferous, with Dinosaurs and Crocodyliformes being known from the formation.

Geology

Lithology

The Lithology of the formation is a sequence of red, pink, purple and occasionally white colored sandstones, conglomerates and mudstones. The Mtuka member is 160–180 m thick in the type section, and is typified by coarser sandstone, a higher frequency of conglomerates, higher proportions of extraformational clasts, thicker and a greater frequency of overbank siltstone and mudstone lenses and a higher proportion of paleosols. While the Namba member is between 340–360 m in the type section, and is less variable in facies, predominated by very fine-to medium-grained sandstones with less overbank mudstone and siltstone lenses. ^[1]

Vertebrate paleofauna

Fish

Fish of the Galula Formation
Genus	Species	Locality	Stratigraphic position	Abundance	Notes	Images
Lupaceradotus	L. useviaensis	RRBP 2004-06-30			Lungfish
Ceratodontidae	Indeterminate		Mtuka Member		Lungfish

Crocodyliformes

Crocodyliformes of the Galula Formation
Genus	Species	Locality	Stratigraphic position	Abundance	Notes	Images
Pakasuchus [3]	P. kapilimai	RRBP 2007-04 [3]	Namba Member [3]	[Two] skulls and an articulated skeleton. [3]	A notosuchian crocodyliform with mammal-like teeth. [3]
Rukwasuchus [4]	R. yajabalijekundu	Namba 2 [4]	Middle Namba member [4]	A partial skull and isolated teeth. [4]	A notosuchian crocodyliform, and the only known sub-Saharan peirosaurid from Africa. [4]
Notosuchia [5]	Indeterminate		Namba Member [5]

Dinosaurs

Dinosaurs of the Galula Formation
Genus	Species	Locality	Stratigraphic position	Abundance	Notes	Images
Mnyamawamtuka [6]	M. moyowamkia		Mtuka Member [6]	An anterior cervical vertebral neural arch, cervical vertebral centra, partial dorsal vertebrae, sacral neural arch, partial sacral centra, sacral ribs, caudal vertebral neural arches, centra, chevrons, numerous dorsal rib fragments, scapula, sternal plate, humeri, partial ulna, metacarpal I, metacarpal III, partial ischium, partial pubis, partial femora, tibiae, fibula, metatarsal I, metatarsal II, metatarsal III, metatarsal IV, metatarsal V, pedal phalanges, ungual, and numerous unidentifiable fragments. [6]	A basal lithostrotian titanosaur with heart-shaped caudal vertebrae. [6]
Rukwatitan [7]	R. bisepultus	Locality RRBP 2007-02 (Namba 2) [6]	Middle Namba member [6]	Posterior cervical vertebrae, partial anterior dorsal vertebral neural arch, anterior caudal vertebrae, middle caudal vertebrae, chevrons, multiple partial dorsal ribs, distal scapula, partial coracoids, humerus, partial ulna, ilium, and proximal pubis. [6]	A basal lithostrotian titanosaur. [6]
Shingopana [5]	S. songwensis	TZ-07 [6]	Namba Member [5]	An angular, partial anterior cervical vertebra, partial middle-to-posterior cervical vertebrae, partial cervical ribs, partial dorsal ribs, humerus, pubis, and many incomplete and/or unidentifiable fragments pertaining to the axial skeleton. [6]	A lithostrotian titanosaur. [6]
Theropoda [8]	Indeterminate		Mtuka and Namba Members [8]	A pair of articulated proximal caudal vertebrae, and 11 teeth. [5]	An indeterminate theropod. [5]

Turtles

Turtles of the Galula Formation
Genus	Species	Locality	Stratigraphic position	Abundance	Notes	Images
Testudines [5]	Indeterminate		Mtuka and Namba Members. [5]	Plastron and carapace fragments. [5]

Mammals

Mammals of the Galula Formation
Genus	Species	Locality	Stratigraphic position	Abundance	Notes	Images
Galulatherium [9]	G. jenkinsi	TZ-07	Namba Member	Left dentary	Probable Gondwanathere [10]

References

1. Roberts, Eric M.; O’Connor, Patrick M.; Stevens, Nancy J.; Gottfried, Michael D.; Jinnah, Zubair A.; Ngasala, Sifael; Choh, Adeline M.; Armstrong, Richard A. (May 2010). "Sedimentology and depositional environments of the Red Sandstone Group, Rukwa Rift Basin, southwestern Tanzania: New insight into Cretaceous and Paleogene terrestrial ecosystems and tectonics in sub-equatorial Africa". Journal of African Earth Sciences. 57 (3): 179–212. Bibcode:2010JAfES..57..179R. doi:10.1016/j.jafrearsci.2009.09.002. ISSN   1464-343X.
2. Widlansky, Sarah J.; Clyde, William C.; O'Connor, Patrick M.; Roberts, Eric M.; Stevens, Nancy J. (March 2018). "Paleomagnetism of the Cretaceous Galula Formation and implications for vertebrate evolution". Journal of African Earth Sciences. 139: 403–420. Bibcode:2018JAfES.139..403W. doi: 10.1016/j.jafrearsci.2017.11.029 . ISSN   1464-343X.
3. O’Connor, Patrick M.; Sertich, Joseph J. W.; Stevens, Nancy J.; Roberts, Eric M.; Gottfried, Michael D.; Hieronymus, Tobin L.; Jinnah, Zubair A.; Ridgely, Ryan; Ngasala, Sifa E. (August 2010). "The evolution of mammal-like crocodyliforms in the Cretaceous Period of Gondwana". Nature. 466 (7307): 748–751. Bibcode:2010Natur.466..748O. doi:10.1038/nature09061. ISSN   0028-0836. PMID   20686573. S2CID   4405106.
4. Sertich, Joseph J. W.; O’Connor, Patrick M. (2014-04-16). "A new crocodyliform from the middle Cretaceous Galula Formation, southwestern Tanzania". Journal of Vertebrate Paleontology. 34 (3): 576–596. Bibcode:2014JVPal..34..576S. doi:10.1080/02724634.2013.819808. ISSN   0272-4634. S2CID   16644660.
5. Gorscak, Eric; O'Connor, Patrick M.; Roberts, Eric M.; Stevens, Nancy J. (2017-07-04). "The second titanosaurian (Dinosauria: Sauropoda) from the middle Cretaceous Galula Formation, southwestern Tanzania, with remarks on African titanosaurian diversity" . Journal of Vertebrate Paleontology. 37 (4): e1343250. Bibcode:2017JVPal..37E3250G. doi:10.1080/02724634.2017.1343250. ISSN   0272-4634. S2CID   90885040.
6. Gorscak, Eric; O’Connor, Patrick M. (2019). "A new African titanosaurian sauropod dinosaur from the middle Cretaceous Galula Formation (Mtuka Member), Rukwa Rift Basin, southwestern Tanzania". PLoS ONE . 2 (14): e0211412. Bibcode:2019PLoSO..1411412G. doi: 10.1371/journal.pone.0211412 . PMC   6374010 . PMID   30759122.
7. Gorscak, Eric; O'Connor, Patrick M.; Stevens, Nancy J.; Roberts, Eric M. (2014-07-29). "The basal titanosaurianRukwatitan bisepultus(Dinosauria, Sauropoda) from the middle Cretaceous Galula Formation, Rukwa Rift Basin, southwestern Tanzania". Journal of Vertebrate Paleontology. 34 (5): 1133–1154. Bibcode:2014JVPal..34.1133G. doi:10.1080/02724634.2014.845568. ISSN   0272-4634. S2CID   677002.
8. O’Connor, Patrick M.; Gottfried, Michael D.; Stevens, Nancy J.; Roberts, Eric M.; Ngasala, Sifa; Kapilima, Saidi; Chami, Remigius (March 2006). "A new vertebrate fauna from the Cretaceous Red Sandstone Group, Rukwa Rift Basin, Southwestern Tanzania". Journal of African Earth Sciences. 44 (3): 277–288. Bibcode:2006JAfES..44..277O. doi:10.1016/j.jafrearsci.2005.11.022. ISSN   1464-343X.
9. OConnor, Patrick; Krause, David; Stevens, Nancy; MacPhee, Ross; Groenke, Joseph; Kalthoff, Daniela (2019). "A new mammal from the Upper Cretaceous (Turonian–Campanian) Galula Formation, southwestern Tanzania". Acta Palaeontologica Polonica. 64. doi: 10.4202/app.00568.2018 .
10. KRAUSE, DAVID W.; GOTTFRIED, MICHAEL D.; O’CONNOR, PATRICK M; ROBERTS, ERIC M. (2003). "A Cretaceous mammal from Tanzania" (PDF). Acta Palaeontologica Polonica. 48 (3): 321–330.