Waterloo Farm lagerstätte

The Waterloo Farm lagerstätte is a Famennian lagerstätte in South Africa that constitutes the only known record of a near-polar Devonian coastal ecosystem.

Reconstruction of paleoenvironment of Waterloo Farm.
Waterloo Farm in 2016.

History and discovery edit

 
Waterloo Farm in 1988.
 
Waterloo Farm main fossil site in 1999 preceding roadworks.
 
Robert Gess, main researcher of Waterloo Farm Lagerstätte

The Waterloo Farm Lagerstätte is an approximately 360 million year old Famennian (latest Devonian) fossil-rich locality of the Witpoort Formation (Witteberg Group, Cape Supergroup) in Makhanda (former Grahamstown) within the Eastern Cape Province, South Africa.[1][2] Before its discovery very little was known of life during the Famennian (see Late Devonian extinction) in what is now southern Africa. This is largely due to the fact that fossils in the Witpoort Formation generally occur in black anaerobically deposited metashale that rapidly degrades near surface and is therefore rarely seen in natural outcrop.[3][4] As is the case with many other scientific discoveries, the discovery of Waterloo Farm was accidental.[5]

Uprisings against the apartheid system in South Africa had by the mid-1980s escalated to violent protests, particularly in the ‘townships’ (designated black residential areas). Prior to that the N2, the main road linking the industrial ports of Port Elizabeth (now Gqeberha) and East London, ran through then Grahamstown, including its township.[5] By 1985, protests and stoning of cars had made it unsafe for traffic to drive through the townships.[5] As a result the local government proposed the construction of a new road that would serve as a bypass around the townships.[5] Due to limited options, it was decided that the bypass would be constructed through the valleyed countryside to the south of then Grahamstown.[5] This involved excavation of extensive road cuttings through hills and spurs of the Rietberg and utilisation of the resultant rubble to build viaducts across the intervening valleys.[5] Amongst the small farms from which land was appropriated for the road was Waterloo Farm, owned by Rhodes University Botany professor, Roy Lubke - with one cutting passing virtually through the farm yard.[5] At a braai (barbeque) held by Roy Lubke one afternoon, a colleague Dr Mark Aken wandered off to the top of the cutting and peered down the slope. He returned to his colleagues to inform them that there were plant fossils in the disturbed black shale. Roy Lubke mentioned this to Dr Fred Gess, an entomologist, who passed the information on to his son Robert Gess. As Robert Gess had a great interest in the fossils of the Eastern Cape he immediately made his way out to the roadworks where he was struck by the uniquely well-preserved nature of the fossils. With the encouragement of his supervisor and mentor Dr Norton Hiller of the Rhodes Geology Department, he started assembling a collection of the fossils.[5] In 1991 Fiona Taylor, an honours student of Dr Hiller, conducted a short study on the geological context of the deposit, and also published a preliminary note on the fossils, including some of those from Gess’ collection. During a short combined excavation by Gess and Taylor, more material was found including remains of large armour-plated (placoderm) fish, later identified as Africa’s only known species of Bothriolepis. Taylor’s sedimentological work was presented in an article titled “Late Devonian shoreline changes: an analysis of Witteberg Group stratigraphy in the Grahamstown area” published in 1992 (Hiller and Taylor).[3] In 1993, Hiller employed Robert Gess to conduct a thorough palaeontological study and his excavations continued until 1995, after the emigration of Dr Hiller. This phase of research resulted in a number of papers, which were the subject of his master’s degree.[5][4]

By the mid-90’s, the road cutting was frequently collapsing due to the dip direction of the strata being towards the road.[5] This led to a near permanent closure of one lane for safety reasons.[5] After there had been a failed attempt to mitigate the situation with steel barriers in the mid-nineties, the newly established South African National Road Agency Limited (SANRAL) published a call for tenders to upgrade the road.[5] This would prove a propitious opportunity for Robert Gess as, by this time, he was struggling to secure further funding for excavations and research.[5] In September 1999, Gess, who had taken up residence in Bathurst (45 km away from Makhanda), heard that a group of consulting engineers from Jeffares and Green (now known as JG Africa) had been awarded the tender to cut back and stabilise the cuttings.[5] He immediately contacted the company and SANRAL to inform them of the sensitivity of the site.[5] SANRAL made funds available for Gess to rescue some of the shale for scientific research.[5] This was hand mined in blocks by Gess and a team under his direction before being transported on a flat-bed truck to his property in Bathurst.[5] Gess built a shed roof over the sample to protect them from the rapid decay that characterises the shale when exposed to weather.[5] It is from meticulous excavation of these recued blocks that most subsequent discoveries have been and continue to be made.[5] A similar process during further roadworks in 2007 and 2008 yielded an even larger haul of fossiliferous blocks which are stored in sheds constructed by SANRAL.[5]

The fossils are housed and researched by the Devonian Ecosystems project, (funded by the Millennium Trust and South African Centre of Excellence in Palaeosciences) in the Albany Museum’s Devonian lab at 87 Beaufort Street, Makhanda (formerly Rhini or Grahamstown). They have provided the material for extensive research by Dr Rob Gess and his collaborators, and an ongoing stream of significant papers.[1][6][7][8]

Contributions to palaeontological material edit

Waterloo Farm is a globally significant site, providing the only record of a high latitude (near polar) coastal ecosystem, overturning numerous assumptions about high latitude conditions during the latest Devonian.[9][1][7] Previous sparse evidence from sub-Saharan Africa, South America and Antarctica had previously led researchers to believe that high latitude conditions precluded extensive vegetation of land and high vertebrate diversity, and that for example Devonian tetrapods only occurred within tropical settings.[10] Waterloo farm has totally disrupted such beliefs, providing evidence for a diversely vegetated adjacent terrestrial habitat with plants including Archaeopteris trees, a diverse estuarine vertebrate fauna[1] and the only known non-tropical Devonian tetrapods.[9] Exceptional soft tissue preservation at Waterloo Farm is unique for a Famennian estuary and allows for reconstruction of an entire estuarine ecosystem,[7] grading from brackish to more marine conditions and including delicate waterweeds,[11] invertebrates[12] and diverse vertebrates.[13][9]  As yet 25 species have been diagnosed from Waterloo Farm and many others provisionally identified. An excess of 50 organisms are however believed to be represented in the extensive collections of the Devonian Ecosystems Project. Together this represents the most holistically studied Devonian tetrapod-bearing locality. Insights provided by the unique soft tissue preservation at the site are also making major contributions to evolutionary biology, such as a growth series of ancient lampreys (Priscomyzon riniensis), that have overturned major, long held, perspectives on vertebrate origins.[7]

Site characteristics edit

 
One of the sheds of shale blocks rescued (with the help of SANRAL) from Waterloo Farm roadworks in 2008, for ongoing scientific excavation.
 
Waterloo Farm during the excavation in 1985.

Witpoort Formation black shales within the Eastern Cape often exhibit cyclical changes in composition, which likely reflect (potentially seasonal) fluctuations in water salinity. Water stratification within the estuarine lake frequently led to anoxic bottom waters, resulting in episodes of exceptional preservation.[14]

Witpoort Formation sediments were deeply buried due to continued basinal subsidence through the Carboniferous, and were subsequently metamorphosed during the massive Permian aged Cape Fold Belt orogenesis.[15] Hundreds of millions of years of erosion and uplift brought the Waterloo Farm shales back up to near surface, they were exposed in 1985, in new road cuttings south of Makhanda/Grahamstown, during construction of a bypass road. On-site excavations were conducted in the 1990s, but the instability of the road cutting led to it being cut back in 1999 and in 2008. On both occasions large quantities of shale were rescued which provides for ongoing excavation. Decades of research has revealed the most important Late Devonian fossil site from what was the southern portion of Gondwanan region incorporating present-day sub-Saharan Africa, South America and western Antarctica.[16] Because the original fine black mud was often very low in oxygen, plants and animals rapidly buried in it sometimes left behind impressions of their soft parts. This is extremely rare in the fossil record which normally only preserves bones, teeth and other hard bits. Exceptionally, what is recorded is the remains of an entire estuarine ecosystem, from delicate waterweeds and seaweeds to small clams, baby fish and the bones of larger fish. Land plants that grew nearby are also preserved, from the remains of small undergrowth species to fronds from the earliest types of trees.[17]

Fossils edit

More than 20 species new to science have been named from Waterloo Farm, which probably represent about a third of the total number of taxa indicated by remains preserved in the shale. Taxa include the tetrapods Tutusius umlambo and Umzantsia amazana,[18] which are Africa's earliest known tetrapods and the only non-tropical Devonian tetrapods known. The first described fossils from Waterloo Farm comprise remains of sub-Saharan Africa's earliest woody trees (Archaeopteris notosaria). Other fossils from Waterloo Farm include the oldest known land-living animal from Gondwana (the scorpion Gondwanascorpio emzantsiensis),[19] the oldest fossil lamprey in the world (Priscomyzon riniensis)[20] and Africa's oldest coelacanth from the world's earliest known coelacanth nursery (Serenichthys kowiensis).[21]

Other species represented include several species of armour plated (placoderm) fish, spiny finned (acanthodian) fish, sharks, ray-finned (actinopterygian) fish, a range of lobe-finned fish, bivalves; seaweeds; charophyte waterweeds, and a diverse range of plants.

Paleobiota edit

Animalia edit

Vertebrata edit

Agnatha edit
Agnatha
Genus Species Notes Images
Priscomyzon[20] P. riniensis The oldest known lamprey, known from multiple growth series.[7]
 
Placodermi edit
Placodermi
Genus Species Notes Images
Bothriolepis[22] B. africana Antiarch placoderm. Species of Bothriolepis known from highest paleolatitude.
 
Groenlandaspis[22] G. riniensis A groenlandaspidid arthrodiran placoderm. Probably the most common vertebrate in environment.
 
Africanaspis[23][22] A. doryssa A groenlandaspidid placoderm.
 
A. edmountaini
 
Arthrodira indet. At least two taxa are known.[17]
Acanthodii edit
Acanthodii
Genus Species Notes Images
Diplacanthus[24] D. acus Exceptionally deep-bodied and long-spined diplacanthiform acanthodian. Redescription of genus did not considered it as a species of Diplacanthus.[25]
 
Gyracanthides[17][26] G. riniensis
 
Diplacanthidae indet.[17]
Acanthodiformes indet.[17]
Chondrichthyes edit
Chondrichthyes
Genus Species Notes Images
Plesioselachus[27][28] P. macracantha 0.5–1 m (1 ft 8 in – 3 ft 3 in) long chondrichthyan with long spine.
 
Antarctilamna[28] A. ultima Large-sized elasmobranch. Known from multiple skeletal materials and complete juvenile.
 
Actinopterygii edit
Actinopterygii
Genus Species Notes Images
Actinopterygii indet.[17]
Sarcopterygii (includes Tetrapoda) edit
Sarcopterygii
Genus Species Notes Images
Serenichthys[21] S. kowiensis Coelacanth known from complete juvenile specimens.
 
Hyneria[29] H. udlezinye Up to 2.7 m (8 ft 10 in) long tristichopterid.
 
Rhizodontida indet.[17]
Isityumzi[30] I. mlomomde Lungfish known from parasphenoid bones.
 
Tutusius[18] T. umlambo Early tetrapod. First known African Devonian tetrapods.
 
Umzantsia[18] U. amazana
 

Invertebrates edit

Mollusca edit
Mollusca
Genus Species Notes Images
Naiadites[31][32] N. devonicus Pteriid bivalve. Only known species of Naiadites from Devonian.
 
Brachiopoda edit
Brachiopoda
Genus Species Notes Images
Dignomia[33] D. sp. Described from newly found site in Witpoort Formation, not exactly from Waterloo Farm
Arthropoda edit
Arthropoda
Genus Species Notes Images
Hibbertopteridae indet.[17] 1.5 m (4 ft 11 in) long sweep-feeding stylonurine eurypterid. Described as "Cyrtoctenid", which is later considered as a growth stage of hibbertopterid.
 
Gondwanascorpio[19] G. emzantsiensis Partially known scorpion.
 

Plantae edit

Algae edit

Rhodophyta or Phaeophyta edit
Rhodophyta or Phaeophyta
Genus Species Notes Images
Hungerfordia[34][35] H. fionae Algae with unknown affinity, possibly brown algae.
 
Yeaia[34][35] Y. africana Brown algae.
Charophyta edit
Charophyta
Genus Species Notes Images
Hexachara[36][35] H. setacea Charophyte algae.
 
H. riniensis
 
Octochara[36][35] O. crassa
 
O. gracilis

Tracheophyta edit

Uncertain edit
Uncertain
Genus Species Notes Images
Flabellopteris[37] F. lococannensis Euphyllophyte with uncertain classification.
Zosterophyllopsida edit
Zosterophyllopsida
Genus Species Notes Images
Zosterophyll indet.[38]
Lycopsida edit
Lycopsida
Genus Species Notes Images
Colpodexylon[39] C. mergae Lycopsid in the order Protolepidodendrales.
C. pullumpedes
Leptophloeum[40] L. rhombicum A lycophyte.
Kowieria[41] K. alveoformis A lycopsid lycophyte.
Iridopteridales edit
Iridopteridales
Genus Species Notes Images
Iridopteridales indet.[17]
Sphenopsida edit
Sphenopsida
Genus Species Notes Images
Rinistachya[42] R. hilleri Sphenopsid. Only sphenopsid known from the Devonian of Gondwana.
 
Progymnospermopsida edit
Sphenopsida
Genus Species Notes Images
Archaeopteris[43] A. notosaria A progymnosperm tree. The only high latitude species of Archaeopteris as yet described.
 


References edit

  1. ^ a b c d Gess, Robert W.; Whitfield, Alan K. (August 2020). "Estuarine fish and tetrapod evolution: insights from a Late Devonian (Famennian) Gondwanan estuarine lake and a southern African Holocene equivalent". Biological Reviews. 95 (4): 865–888. doi:10.1111/brv.12590. ISSN 1464-7931. PMID 32059074. S2CID 211122587.
  2. ^ Frey, Linda; Coates, Michael; Ginter, Michal; Klug, Christian; Ginter, Michał (2017-07-07). "Skeletal remains of Phoebodus politus Newberry 1889 (Chondrichthyes: Elasmobranchii) from a Famennian Konservatlagerstätte in the eastern Anti-Atlas (Morocco) and its ecology". Ichthyolith Issues. Chęciny, Poland: University of Warsaw: 36. doi:10.5167/uzh-138397. S2CID 197550063.
  3. ^ a b Hiller & Taylor, Norton & Fiona (1992). "Late Devonian shoreline changes: an analysis of Witteberg Group stratigraphy in the Grahamstown area". South African Journal of Geology. 5: 203–214 – via AJA.
  4. ^ a b Wolfgang, Gess, Robert (2012-05-14). High latitude Gondwanan famennian biodiversity patterns : evidence from the South African Witpoort Formation (Cape Supergroup, Witteberg Group). University of the Witwatersrand. OCLC 811026675.{{cite book}}: CS1 maint: multiple names: authors list (link)
  5. ^ a b c d e f g h i j k l m n o p q r s t Gess, Robert Wolfgang (2002). "The palaeoecology of a coastal lagoon of the Witpoort Formation (Upper Devonian, Famennian) in the Eastern Cape Province, South Africa". University of Fort Hare, South Africa: 6–11 – via Fort Hare University, Southa Africa.
  6. ^ Gess, Robert W.; Coates, Michael I.; Rubidge, Bruce S. (October 2006). "A lamprey from the Devonian period of South Africa". Nature. 443 (7114): 981–984. Bibcode:2006Natur.443..981G. doi:10.1038/nature05150. ISSN 0028-0836. PMID 17066033. S2CID 4302716.
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  19. ^ a b Gess, Robert W. (December 2013). "The Earliest Record of Terrestrial Animals in Gondwana: A Scorpion from the Famennian (Late Devonian) Witpoort Formation of South Africa". African Invertebrates. 54 (2): 373–379. Bibcode:2013AfrIn..54..373G. doi:10.5733/afin.054.0206.
  20. ^ a b Gess, Robert W.; Coates, Michael I.; Rubidge, Bruce S. (October 2006). "A lamprey from the Devonian period of South Africa". Nature. 443 (7114): 981–984. Bibcode:2006Natur.443..981G. doi:10.1038/nature05150. PMID 17066033. S2CID 4302716.
  21. ^ a b Gess, Robert W.; Coates, Michael I. (1 October 2015). "Fossil juvenile coelacanths from the Devonian of South Africa shed light on the order of character acquisition in actinistians". Zoological Journal of the Linnean Society. 175 (2): 360–383. doi:10.1111/zoj.12276.
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  35. ^ a b c d Gess, Robert W.; Whitfield, Alan K. (2020). "Estuarine fish and tetrapod evolution: Insights from a Late Devonian (Famennian) Gondwanan estuarine lake and a southern African Holocene equivalent". Biological Reviews. 95 (4): 865–888. doi:10.1111/brv.12590. PMID 32059074. S2CID 211122587.
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  37. ^ Gess, Robert W.; Prestianni, Cyrille (2022-02-01). "Flabellopteris lococannensis gen. et sp. nov.: A new fern-like plant from the Famennian of South Africa". Review of Palaeobotany and Palynology. 297: 104585. Bibcode:2022RPaPa.29704585G. doi:10.1016/j.revpalbo.2021.104585. ISSN 0034-6667. S2CID 245209478.
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  39. ^ Harris, Christopher; Gess, Robert W.; Prestianni, Cyrille; Bamford, Marion K. (2021-10-01). "A Late Devonian refugium for Colpodexylon (Lycopsida) at high latitude". Review of Palaeobotany and Palynology. 293: 104481. Bibcode:2021RPaPa.29304481H. doi:10.1016/j.revpalbo.2021.104481. ISSN 0034-6667.
  40. ^ Prestianni, C.; Gess, R. W. (1 October 2014). "The rooting system of Leptophloeum Dawson: New material from the Upper Devonian, Famennian Witpoort Formation of South Africa". Review of Palaeobotany and Palynology. 209: 35–40. Bibcode:2014RPaPa.209...35P. doi:10.1016/j.revpalbo.2014.05.007.
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