Tendaguru Formation
Stratigraphic range: ?Callovian-Hauterivian ~165–130 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Type	Geological formation
Sub-units	See text
Underlies	Makonde Formation
Overlies	Neoproterozoic gneiss basement
Thickness	>110 m (360 ft)
Lithology
Primary	Sandstone
Other	Shale, siltstone, clay, conglomerate, limestone
Location
Coordinates	9°42′S 39°12′E / 9.7°S 39.2°E / -9.7; 39.2
Approximate paleocoordinates	29°24′S 16°42′E / 29.4°S 16.7°E / -29.4; 16.7
Region	Lindi Region
Country	Tanzania
Extent	Mandawa Basin
Type section
Named for	Tendaguru Hill
Named by	Janensch & Hennig
Year defined	1914
Tendaguru Formation (Tanzania)

The Tendaguru Formation, or Tendaguru Beds are a highly fossiliferous formation and Lagerstätte located in the Lindi Region of southeastern Tanzania. The formation represents the oldest sedimentary unit of the Mandawa Basin, overlying Neoproterozoic basement, separating by a long hiatus and unconformity. The formation reaches a total sedimentary thickness of more than 110 metres (360 ft). The formation ranges in age from the late Middle Jurassic to the Early Cretaceous, Oxfordian to Hauterivian stages, with the base of the formation possibly extending into the Callovian.

The Tendaguru Formation is subdivided into six members; from oldest to youngest Lower Dinosaur Member, the Nerinella Member, the Middle Dinosaur Member, Indotrigonia africana Member, the Upper Dinosaur Member, and the Rutitrigonia bornhardti-schwarzi Member. The succession comprises a sequence of sandstones, shales, siltstones, conglomerates with minor oolitic limestones, deposited in an overall shallow marine to coastal plain environment, characterized by tidal, fluvial and lacustrine influence with a tsunami deposit occurring in the Indotrigonia africana Member. The climate of the Late Jurassic and Early Cretaceous was semi-arid with seasonal rainfall and the eustatic sea level was rising in the Late Jurassic from low levels in the Middle Jurassic. Paleogeographical reconstructions show the Tendaguru area was located in the subtropical southern hemisphere during the Late Jurassic.

The Tendaguru Formation is considered the richest Late Jurassic strata in Africa. The formation has provided a wealth of fossils of different groups; early mammaliaforms, several genera of dinosaurs, crocodyliforms, amphibians, fish, invertebrates and flora. More than 250 tonnes (250 long tons; 280 short tons) of material was shipped to Germany during early excavations in the early twentieth century. The faunal assemblage of the Tendaguru is similar to the Morrison Formation of the central-western United States, with an additional marine interbed fauna not present in the Morrison.

The dinosaur fauna found in the formation is similar to that of other highly fossiliferous stratigraphic units of the Late Jurassic; among others the Kimmeridge and Oxford Clays of England, the Sables de Glos, Argiles d'Octeville, Marnes de Bléville of France, the Alcobaça, Guimarota and Lourinhã Formations of Portugal, the Villar del Arzobispo Formation of Spain, the Shishugou, Kalazha and Shangshaximiao Formations in China, the Toqui Formation of Chile and Cañadón Calcáreo Formation and the Morrison Formation, with the presence of dinosaurs with similar counterparts, e.g., Brachiosaurus and Stegosaurus in the Morrison, and Giraffatitan and Kentrosaurus in the Tendaguru.^[1]

Description

The Tendaguru Formation represents the oldest sedimentary unit in the Mandawa Basin, directly overlying Neoproterozoic basement consisting of gneiss. The contact contains a large hiatus, a missing sequence of stratigraphy, spanning the Paleozoic, Triassic and Early Jurassic. The formation is unconformably overlain by late Early Cretaceous sediments of the Makonde Formation, that forms the top of several plateaus; Namunda, Rondo, Noto, and Likonde-Kitale.^[2]

Based on extended geological and paleontological observations the "Tendaguruschichten" (Tendaguru Beds) were defined by Werner Janensch as expedition leader and Edwin Hennig in 1914 to define a sequence of Late Jurassic to Early Cretaceous strata, exposed in the Tendaguru area, which is named after Tendaguru Hill.^[3]

Stratigraphy

The Tendaguru is divided into 6 members, which represent different depositional environments, with the 'Dinosaur Beds' representing terrestrial facies while the beds with genus/species names represent marine interbeds with shallow marine to lagoonal facies. In ascending order these are: the Lower Dinosaur Member, the Nerinella Member, the Middle Dinosaur Member, Indotrigonia africana Member, the Upper Dinosaur Member, and the Rutitrigonia bornhardti-schwarzi Member.^[4]

Stratigraphy of the Tendaguru Formation^[5]

Formation	Time period	Member	Lithology	Thickness	Image
Makonde	Early Albian Aptian		Fine to medium grained sandstones, intercalated conglomerates, siltstones and claystones	~200 m (660 ft)
	Barremian	Unconformity
Tendaguru	Hauterivian Valanginian	Rutitrigonia bornhardti-schwarzi	Fine to medium grained sandstones with basal conglomerate	5–70 m (16–230 ft)
	Berriasian	Unconformity
	Tithonian	Upper Dinosaur	Ripple cross bedded fine grained sandstones and siltstones with intercalated claystone and micritic carbonates	~32 m (105 ft)
		Indotrigonia africana	Calcite cemented sandstones, conglomerate beds, thin clay and silt layers with sandy limestones	20–50 m (66–164 ft)
	Late Kimmeridgian
		Middle Dinosaur	Ripple cross bedded fine grained calcareous sandstones and siltstones and massive to crudely bedded silt and claystones	13–30 m (43–98 ft)
	Kimmeridgian Oxfordian	Nerinella	Trough cross bedded sandstone to massive sandstone	5–45 m (16–148 ft)
	Mid Oxfordian ?Callovian	Lower Dinosaur	Cross bedded fine grained sandstones and siltstones, with Interbedded clay-rich siltstones	>20 m (66 ft)
	Early Jurassic	Hiatus
	Triassic
	Paleozoic
Basement	Neoproterozoic		Gneiss

Paleogeography and depositional environment

Paleogeography

The Tendaguru Formation was deposited in the Mandawa Basin, a post-Karoo,^[6] Mesozoic rift basin located between the Ruvu Basin and Rufiji Trough to the north and the Ruvuma Basin to the south.^[7] To the west of the basin, Archean and Early Proterozoic basement rocks crop out.^[8] The main rift phase in present-day southeastern Africa led to the separation of Madagascar and the then-connected Indian subcontinent happened during the Early Cretaceous.^[9] The Songo Songo and Kiliwani gas fields are located just offshore the basin.^[10][11]

At time of deposition was undergoing a semi-arid climate with coastal influences that maintained somewhat higher moisture levels than seen inland.^[12] The upper parts of the formation, the Middle Dinosaur and Rutitrigonia bornhardti-schwarzi Members in particular, showed prevailing semiarid conditions with pronounced dry seasons, based on palynologic analysis.^[13] The Tendaguru fauna was stable through the Late Jurassic.^[14]

During the Late Jurassic and Early Cretaceous, the Gondwana paleocontinent was breaking up and the separation of the Laurasian and Gondwana supercontinents resulted from the connection of the Tethys Ocean with the proto-Atlantic and the Pacific Ocean. In addition, the South Atlantic developed towards the end of the Late Jurassic with the separation of South America and Africa. Africa became increasingly isolated from most other continents by marine barriers from the Kimmeridgian into the Early Cretaceous, but retained a continental connection with South America. Global sea levels dropped significantly in the Early Jurassic and remained low through the Middle Jurassic but rose considerably towards the Late Jurassic, deepening the marine trenches between continents.^[15]

Depositional environment

The sedimentary rocks and fossils record a repeated shift from shallow marine to tidal flat environments indicating that the strata of the Tendaguru Formation were deposited near an oscillating strandline which was controlled by sea level changes. The three dinosaur-bearing members are continental to marginal marine and the three sandstone-dominated members are marginal marine in origin.^[16]

Nerinella Member

The composition of benthic molluscs and foraminifera, euhaline to mesohaline ostracods, and dinoflagellate assemblages indicate marine, shallow water conditions for the Nerinella Member, in particular for the lower part. Sedimentation occurred as tidal channel fills, subtidal and tidal sand bars, minor storm layers (tempestites), and beach deposits. Overall, the Nerinella Member represents a variety of shallow subtidal to lower intertidal environments influenced by tides and storms.^[17]

Middle Dinosaur Member

The sedimentological characteristics of the basal part of the Middle Dinosaur Member suggest deposition on tidal flats and in small tidal channels of a lagoonal paleoenvironment. The ostracod Bythocypris sp. from the member indicates polyhaline to euhaline conditions. Slightly higher up, a faunal sample dominated by the bivalve Eomiodon and an ostracod assemblage composed of brackish to freshwater taxa is indicative of a brackish water paleoenvironment with distinct influx of freshwater as revealed by the nonmarine ostracod genus Cypridea, charophytes, and other freshwater algae. The paleoenvironment of the ostracod assemblages of the Middle Dinosaur Member changed upsection from a marine setting in the basal parts through alternating marine-brackish conditions to freshwater conditions in the higher parts of this member.^[17] The highly sporadic occurrence, in this part of the section, of molluscs typical of marginal marine habitats indicates only a very weak marine influence,^[18] at sabkha-like coastal plains with ephemeral brackish lakes and ponds are recorded in the upper part of the Middle Dinosaur Member. This part also contains pedogenic calcretes indicating subaerial exposure and the onset of soil formation.^[17] The calcrete intraclasts within adjacent sandstone beds testify to erosive reworking of calcrete horizons.^[18] The presence of crocodyilforms indicates freshwater to littoral environments and adjacent terrestrial areas.^[19]

Indotrigonia africana Member

The coarse-grained sandstone of the lower part of the Indotrigonia africana Member that shows highly variable transport directions is interpreted as deposits of large tidal channels. Grain-size, large-scale sedimentary structures, and the lack of both trace fossils and epifaunal and infaunal body fossils suggest high water energy and frequent reworking. This basal succession passes upward in cross-bedded sandstone and minor siltstone and claystone with flaser or lenticular bedding that are interpreted as tidal flat and tidal channel deposits. Horizontal to low-angle cross-bedded, fine-grained sandstone with intercalated bivalve pavements indicates tidal currents that operated in small flood and ebb tidal deltas and along the coast. Stacked successions of trough cross-bedded, medium- to coarse-grained sandstone of the upper part of the Indotrigonia africana Member are interpreted as tidal channel and sand bar deposits. At some places in the surroundings of Tendaguru Hill, these sediments interfinger with oolitic limestone layers that represent high-energy ooid shoals.^[17]

In the Tingutinguti stream section, the Indotrigonia africana Member exhibits several up to 20 centimetres (7.9 in) thick, poorly sorted, conglomeratic sandstone beds. They contain mud clasts, reworked concretions and/or accumulations of thick-shelled bivalves (mainly Indotrigonia africana and Seebachia janenschi), and exhibit megaripple surfaces. These conglomeratic sandstone layers are interpreted as storm deposits. In the Dwanika and Bolachikombe stream sections, and in a small tributary of the Bolachikombe creek, a discrete, up to 70 centimetres (2.3 ft) thick conglomerate in the lower portion of the Indotrigonia africana Member displays evidence of a tsunami deposit. Overall, lithofacies and the diverse macroinvertebrate and microfossil assemblages of the Indotrigonia africana Member suggest a shallow marine environment. Based on the diverse mesoflora and the abundance of Classopollis, a nearby vegetated hinterland is postulated that was dominated by xerophytic conifers.^[17]

Upper Dinosaur Member

The small-scale trough and ripple cross-bedded fine-grained sandstone at the base of the Upper Dinosaur Member is interpreted as tidal flat deposits. Unfossiliferous sandstone in the upper part was most likely deposited in small fluvial channels in a coastal plain environment, whereas argillaceous deposits were laid down in still water bodies such as small lakes and ponds. Rare occurrences of the ostracod Cypridea and charophytes signal the influence of freshwater, whereas the sporadic occurrence of marine invertebrates suggests a depositional environment close to the sea.^[17]

Rutitrigonia bornhardti-schwarzi Member

Fining upward sequences of the basal part of the Rutitrigonia bornhardti-schwarzi Member are interpreted as tidal channel fills, the overlying fine-grained sandstone, silt- and claystone as tidal flat deposits. From the immediate surroundings of Tendaguru Hill, invertebrates and vertebrates are poorly known and limit the palaeoenvironmental interpretation of this member. The composition of the land-derived sporomorph assemblage suggests a terrestrial vegetation which was dominated by cheirolepidiacean conifers in association with ferns.^[16]

Excavation history

The Tendaguru Beds as a fossil deposit were first discovered in 1906, when German pharmacist, chemical analyst and mining engineer Bernhard Wilhelm Sattler, on his way to a mine south of the Mbemkure River in German East Africa (today Tanzania), was shown by his local staff enormous bones weathering out of the path near the base of Tendaguru Hill, 10 kilometres (6.2 mi) south of Mtapaia (close to Nambiranji village, Mipingo ward, 60 kilometres (37 mi) northwest of Lindi town).^[3][20] Because of its morphology, the hill was locally known as "steep hill": "tendaguru" in the language of the local Wamwera people. Sattler sent a report of the discoveries that found its way to German palaeontologist Eberhard Fraas, then on a round trip through Africa, who visited the site in 1907 and with the aid of Sattler recovered two partial skeletons of enormous size.^[21]

Following the discovery in 1906, teams from the Museum für Naturkunde, Berlin (1907–1913), and the British Museum (Natural History), London (1924–1931) launched a series of collecting expeditions that remain unequalled in scope and ambition. Led by the vision and influence of geologist Wilhelm von Branca, the German expeditions were particularly successful, in large part because the project was taken up as a matter of national ambition (Germany was then a young nation, having been unified by von Bismarck less than 40 years earlier) and enjoyed the benevolence of many wealthy patrons. Eventually, nearly 250 tons of bones, representing an entirely new dinosaur fauna that remains the best understood assemblage from all of former Gondwana, was shipped to Berlin.^[22]

From there, the material was transported to Fraas' institution, the Royal Natural History Collection in Stuttgart, Germany. Fraas described two species in the badly known genus "Gigantosaurus"; G. robustus and G. africanus (today Janenschia robusta and Tornieria africana, respectively).^[21]

German Tendaguru Expedition

The Berlin's Natural History Museum excavated at Tendaguru hill and in the surroundings for four years. From 1909 through 1911, Werner Janensch as expedition leader and Edwin Hennig as assistant directed excavations, while Hans Reck and his wife Ina Reck led the 1912 field season. Other European participants include Hans von Staff. In the rainy seasons the scientists explored the geology of the colony German East Africa on long safaris.

Public discussion about provenance and restitution

In the context of international discussion about the provenance and possible restitution of colonial heritage, as discussed for example in the 2018 report on the restitution of African cultural heritage, both German as well as Tanzanian commentators have called the claim to rightful ownership by the Berlin museum into question. The Tanzanian government has, however, not submitted any official demand for repatriation. German authorities have preferred to offer information on the provenance and research by increasing cooperation between Tanzanian paleontologists and museums with their German counterparts.^[23]

In popular culture

In 1998, an illustrated book in Swahili, whose title translates as Dinosaurs of Tendaguru, was published for young readers in East Africa. It presents a slightly different, fictitious story of the first discovery, which is attributed to a Tanzanian farmer, rather than to the German engineer Sattler.^[24]

Paleontological significance

Possible dinosaur eggs have been recovered from the formation.^[25]

The fauna of the Tendaguru Formation has been correlated with the Morrison Formation of the central-western United States,^[26] several formations in England, among which the Kimmeridge Clay and Oxford Clay, and France (Sables de Glos, Argiles d'Octeville, Marnes de Bléville), the Alcobaça, Guimarota and Lourinhã Formations of Portugal,^[27] the Villar del Arzobispo Formation of Spain, the Shishugou, Kalazha and Shangshaximiao Formations of China, and the Toqui Formation of the Magallanes Basin, Chile and the Cañadón Calcáreo Formation of the Cañadón Asfalto Basin in central Patagonia, Argentina.^[28]

Fossil content

Mammaliaformes

Squamates

Pterosaurs

Pterosaurs reported from the Tendaguru Formation
Genus	Species	Location	Member	Material	Notes	Images
Tendaguripterus	T. recki[35]	Quarry Ig	Middle Dinosaur	A partial mandible with teeth	[35]
?Indeterminate archaeopterodactyloid		Mkoawa Mtwara		Humerus	[35][36]
Indeterminate azhdarchid		Mkoawa Mtwara			[35]
Indeterminate dsungaripteroid			Upper Dinosaur[31]	Humerus	[36]
Pterodactylus	P. maximus	Mkoawa Mtwara			Later determined to be an indeterminate pterodactyloid[35]
	P. brancai	Mkoawa Mtwara		Tibiotarsi[37]	Later determined to be an indeterminate dsungaripteroid[35]
	P. arningi	Mkoawa Mtwara			Later determined to be an indeterminate pterosaur[35]
Rhamphorhynchus	R. tendagurensis	Mkoawa Mtwara			Later determined to be an indeterminate "rhamphorhynchoid"[35]

Ornithischians

Ornithischians reported from the Tendaguru Formation
Genus	Species	Location	Member	Material	Notes	Images
Dysalotosaurus	D. lettowvorbecki	Quarry Ig	Middle Dinosaur	"Large number of mostly disassociated cranial and postcranial elements"	A dryosaurid[25][38]
Kentrosaurus	K. aethiopicus	Quarry Q, Ig, St, S, Ny, Li, XX, r, y, d, Ng, X, H, IX, Om, bb, Ha, XIV, II, IV, V, VIII, G, e, g, Ki	Lower, Middle & Upper Dinosaur	"[Two] composite mounted skeletons, [four] braincases, [seven] sacra, more than [seventy] femora, approximately 25 isolated elements, juvenile to adult"	A stegosaur[25][39]

Sauropods

Sauropods reported from the Tendaguru Formation
Genus	Species	Location	Member	Material	Notes	Images
Australodocus	A. bohetii	Quarry G	Upper Dinosaur	Two neck vertebrae; more undescribed remains destroyed during World War II	[40]Somphospondylan
Dicraeosaurus	D. hansemanni	Quarry Q, m, St, dd, Sa	Lower, Middle & Upper Dinosaur	"Skeleton lacking skull and forelimbs, [two] partial skeletons, isolated vertebrae, and limb elements"	Dicraeosaurid[25][41]
	D. sattleri	Quarry La, s, O, ab, E, M, o, Ob, bb, XIV, G, GD	Middle & Upper Dinosaur	"[Two] partial skeletons without skulls, isolated postcranial remains"	Dicraeosaurid[25][41]
Giraffatitan[25]	G. brancai	Quarry Q, J, Ig, Y, St, dd, S, TL, XX, Ma, JR, Ng, Bo, To, p, t, Lw, D, N, ab, cc, X, IX, Z, T, Aa, l, E, XIV, II, G, e, Ki, No, R, F, XII, GD, XV, Sa, U, i	Lower, Middle & Upper Dinosaur		Brachiosaurid. The new genus Giraffatitan was erected to hold the former Brachiosaurus species, B. brancai after scientists concluded that it was distinct enough from the Brachiosaurus type species, B. altithorax, to warrant such a reclassification.[42]
Janenschia	J. robusta	Quarry dd, P, IX, B, G, Oa, NB	Middle & Upper Dinosaur	Known from hindlimb and forelimb material, left pubis and two right ischia	non-neosauropod eusauropod[25][43]
Tendaguria	T. tanzaniensis	Nambango site	Upper Dinosaur	"[Two] associated cranial dorsal vertebrae"	A turiasaur[25][44]
Tornieria	T. africana	Quarry St, k, MD, A, e, Sa	Middle & Upper Dinosaur	"More than [three] partial skeletons, a few skull elements, [and] many isolated postcranial elements"	Diplodocid[25][45]
Wamweracaudia	W. keranjei			A sequence of caudal vertebrae	Mamenchisaurid[43]
Brachiosaurus	B. brancai	Mkoawa Mtwara		"[Five] partial skeletons, more than [three] skulls, [and] isolated limb elements"	B. brancai was distinct enough from the non-Tendaguru Brachiosaurus type species B. altithorax that it was moved to its own genus, Giraffatitan.[25][42][46]
	B. fraasi				Remains attributed to B. fraasi were later referred to B. brancai, and thus now Giraffatitan[25][42]
Diplodocinae indet.	Indeterminate	Kijenjere	Upper Dinosaur	Partial skull	Belonging to a form that is closely related to Diplodocus[47]
Diplodocidae indet.	Indeterminate	Kijenjere	Upper Dinosaur	Caudal vertebrae and metatarsal	Originally referred to as "Barosaurus africanus"[48]
Diplodocidae indet.	Indeterminate	Trench XIV	Upper Dinosaur	Articulated pedes	Possibly representing two different taxa[49]
Flagellicaudata indet.	Indeterminate		Upper Dinosaur	Braincase	Referred to Flagellicaudata indet. based on the derived characters shared with this group[50]
"The Archbishop"					Brachiosaur, distinct from Giraffatitan[note 1]

Theropods

Theropods reported from the Tendaguru Formation
Genus	Species	Location	Member	Material	Notes	Images
?Abelisauridae indet.	Indeterminate	Quarry TL	Upper Dinosaur	A left tibia, a right tibia, and a femur[51]	Possibly an indeterminate abelisaurid.[51]
Megalosauroidea indet.	Indeterminate	Quarry MW	Upper Dinosaur	left tibia and left astragalus[51]	A large indeterminate megalosauroid.[51]
Elaphrosaurus	E. bambergi	Quarry Ig, dd, ?RD	Middle Dinosaur, ?Upper Dinosaur	"Postcranial skeleton"[52]	An elaphrosaurine noasaurid[25]
Ostafrikasaurus	O. crassiserratus	Quarry Om	Upper Dinosaur	"Tooth"	A tooth of controverisial affinitiies, had either been suggested to have been a spinosaurid or a ceratosaurid.[53][54]
Veterupristisaurus	V. milneri	Quarry St	Middle Dinosaur	"Vertebrae"	The earliest known carcharodontosaurid.[51]
?Allosaurus	?A. tendagurensis	Quarry TL	Middle Dinosaur	A tibia[25][55]	Remains now considered "Tetanurae indet." Possibly a megalosauroid or carcharodontosaurid.[51] Originally referred to Allosauridae'
Ceratosaurus	C. roechlingi	Quarry St, MW	Middle & Upper Dinosaur	Caudal vertebra	Tentatively referred to Ceratosauridae.[51] Originally referred to Allosauridae.
Labrosaurus	L. stechowi	Quarry St, MW	Middle Dinosaur	Teeth	A ceratosaurid, a species of Ceratosaurus.[51] Originally referred to Allosauridae.
?Torvosaurus	T. sp	Quarry St, MW	Upper Dinosaur	Teeth	Includes remains previously referred to "Megalosaurus" ingens - now known as "Torvosaurus sp".[56]

Crocodyliformes

Amphibians

Fish

Genus	Species	Member	Notes	Images
Engaibatis	Engaibatis schultzei	Upper Dinosaur	[58]
Lepidotes	Lepidotes tendaguruensis	Middle Dinosaur	[31]
	L. sp.	Upper & Middle Dinosaur	[59]
Hybodus	Hybodus sp.	Upper Dinosaur	[60]
Lonchidion	Lonchidion sp.	Upper Dinosaur	[61]
Sphenodus	Sphenodus sp.	Upper Dinosaur	[62]

Invertebrates

Gastropods

Genus	Species	Member bold is defining	Notes	Images
Pseudomelania	Pseudomelania dietrichi	Middle Dinosaur	[19]
Promathildia	Promathildia sp.	Middle Dinosaur	[19]
Nerinella	Nerinella cutleri	Nerinella	[63]

Bivalves

Coral

Ostracods

Flora