Twenty million years ago, Lake Manuherikia covered much of the Maniototo Plains of Central Otago. At 5,600 sq km this lake was nine times the size of Lake Taupō, extending all the way from the Waitaki River to the Nevis Valley south of Queenstown.
Although we don’t know how long the lake remained, we know it was there in the early Miocene (about 16 to 19 million years ago). We also know it was surrounded by rich subtropical vegetation.
The edges of the lake were fringed with ferns and swamps. After the lake dried up, its bed became a fossil-rich layer of sediments. During the last 20 years palaeontologists have found fossil plants, fish, birds and other animals in the clay and mudstone of the Manuherikia lake sediments.
This video shows how the land we now call New Zealand was transformed over a period of 40 million years between the Paleocene Period (c60 million years ago) and the Miocene Period (c20 million years ago).
St Bathans Crocodile
New Zealand once had a 3 metre-long crocodile that was about the size of northern Australia’s living freshwater crocodile (Crocodylus johnstoni). Crocodiles were probably the most significant predator at St Bathans.
The presence of a crocodile in Zealandia was first identified from a bone found by palaeobotanist Dr Mike Pole at St Bathans in 1987.Since the team of palaeontogists has been working at St Bathans, nearly 200 crocodile bones and teeth have been recovered from four sites. However, the bones confirming the exact type of crocodile have so far proved elusive. Although several skull and limb bones have been recovered, these have all belonged to different animals.
These crocodiles were covered in bony projections called osteoderms and they had robust limbs. Their lower jaw was shaped unlike any other crocodile, suggesting that they had short, deep faces. There may have even been more than one type of crocodile in Lake Manuherikia.
These crocodiles have no obvious relation to crocodile fossils found in the South West Pacific or Australia. It’s possible that, like the tuatara, they date back to the ancient continent of Gondwana.
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Crocodiles about the size of Australia’s living freshwater crocodile were probably the most significant predator at St Bathans. They were first identified from a bone found in 1987.
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A life-sized model of the St Bathans Crocodile.
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This skull is from a small (about 1 metre long) saltwater crocodile (Crocodylus porosus) from northern Australia. Compared to St Bathans crocodiles, the saltwater crocodile has a longer, narrower snout. This individual is about the same size as many of the St Bathans fossils.
The fossils below are remnants of the St Bathans Crocodile.
Canterbury Museum OR5367
Mata Creek Goby
By far the most common animal fossils preserved in the deposits are fish. Most of the fossils are backbones.
The remains of skull bones and several thousand tiny ear bones, called otoliths, have also been preserved. Fourteen species of fish have been described, all of which belong to families still living in Aotearoa New Zealand today.
Most of the species are in the families that includes whitebait (Galaxiidae) and gobies (Eleotridae) but at least two types of grayling (Retropinnidae) have been found. This proves that most of the freshwater fish families living around Aotearoa New Zealand and southern Australia today were established between 19 and16 million years ago. Most fish species were larger than their living relatives.
The most common animal fossils found at St Bathans are fish. Many are related to whitebait (Galaxiidae) and gobies (Eleotridae). This proves most freshwater fish families living around Aotearoa New Zealand now were present 20 million years ago.
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These well-preserved fish fossils are from Bannockburn near Cromwell.
Canterbury Museum 2012.47.1, 2012.47.2
St Bathans Kiwi
A tiny species of kiwi that may have been able to fly has been identified from three bones.
The St Bathans Kiwi was smaller than any living species of kiwi, with a leg bone (femur) that was shorter and about half the diameter of a Little Spotted Kiwi leg bone (the smallest modern kiwi).
The genus name Proapteryx comes from Latin and means before (pro) Kiwi (Apteryx), indicating that this species precedes modern kiwi in the geological record. The species name micromeros comes from the Latin micro meaning small and meros meaning thigh.
Palaeontologists believe the presence of a small, slender-legged kiwi in Aotearoa New Zealand as much as 20 million years ago indicates that kiwi and their nearest relatives (the gigantic elephant birds of Madagascar) evolved from a small-bodied and possibly flying ancestor.
This bird was probably about the size of a pigeon. It would have weighed between 280 and 380 grams, about a third the weight of the living Little Spotted Kiwi.
This kiwi was smaller than any living species of kiwi, with a leg bone that was shorter and about half the diameter than that of a Little Spotted Kiwi. Some of the bones suggest it may have been able to fly.
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This black fossil is the incomplete end of the left leg bone (tibiotarsus) of Proapteryx micromeros. It is beside the leg bone of the living Little Spotted Kiwi.
Canterbury Museum 2017.37.37, AV39065
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This juvenile Little Spotted Kiwi was about the same size as the St Bathans Kiwi.
Canterbury Museum 2016.412.2124
St Bathans Adzebill
Adzebills are a bizarre group of recently extinct, flightless birds that were only found in Aotearoa New Zealand. These fossils confirm that adzebills have lived in Aotearoa New Zealand for at least 20 million years.
The palaeontologists believe the nearest relatives of adzebills are tiny African birds called flufftails. The St Bathans Adzebill was slightly smaller than the two recently extinct adzebill species.
The St Bathans Adzebill was described from two distinctive backbones. Four other bone fragments found at the same site are believed to be from the same species. The species name proasciarostratus comes from the Latin words pro meaning before, ascia meaning adze and rostratus meaning beaked.
Adzebills are a group of recently extinct, flightless birds, only found in Aotearoa New Zealand. The fossils confirm that Adzebills have lived here for at least 20 million years. Their bizarre bill was shaped like an axehead.
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This fossil (left) is the ball of a right upper leg bone. Next to it is the same bone of an extinct South Island Adzebill.
Fossil: Canterbury Museum 2017.18.612 South Island Adzebill bone: Canterbury Museum AV12683
St Bathans Shelduck
This large duck was similar to the Paradise Shelduck found in Aotearoa New Zealand today but it was not a direct ancestor.
The name Miotadorna is based on the palaeontologists’ conclusion that the species is a Miocene shelduck related to Tadorna (the genus that includes the Paradise Shelduck). The species name reflects that the bird used to live around the old gold mining town of St Bathans, near the fossil sites.
The St Bathans Shelduck is the largest duck found in the fossil sites. There are also at least two as-yet undescribed species of geese which may be related to the recently extinct New Zealand Goose (Cnemiornis).
Although it is not their direct ancestor, Miotadorna sanctibathansi probably resembled the Paradise Shelducks found in Aotearoa New Zealand today. It is the largest of the six duck species found at the St Bathans fossil site.
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The fossil on the left is the upper leg bone of the St Bathans Shelduck. It is probably more closely related to the Common Shelduck shown here, which is found in Eurasia, than the Paradise Shelduck found in Aotearoa New Zealand today.
Fossil: Canterbury Museum 2013.18.2064 Common Shelduck: Canterbury Museum AV37550
The Common Manuherikia Duck was a diving duck a bit smaller than an Australasian Shoveler. It had large salt glands that show it could live in saline water as well as the freshwater Lake Manuherikia.
Manuherikia lacustrina was the commonest bird in Lake Manuherikia and was about the size of the modern Grey Duck found in Aotearoa New Zealand today.
A diving duck about the size of the modern Grey Duck found in Aotearoa New Zealand today. It had large salt glands allowing it to live in saltwater and freshwater. Manuherikia lacustrina was the most common bird in Lake Manuherikia.
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These fossils are the wing and leg bones of the Common Manuherikia Duck, the most common bird at Lake Manuherikia.
Canterbury Museum 2017.37.386, 2017.37.387, 2017.37.388
St Bathans Goose
Waterfowl found at St Bathans includes six duck species and two unnamed geese. These have been mainly identified from the size and form of their upper wing bones (humeri).
The closest relative of both goose species appears to be Australia's Cape Barren Goose.
Palaeontologists have discovered two species of goose at the St Bathans fossil site, but they need to find more bones before either can be named. The closest living relative of both species appears to be Australia’s Cape Barren Goose.
A tiny bittern, the size of the extinct New Zealand Bittern, probably haunted the reeds around the lakebed.
Bartle’s Bittern was a small bittern species possibly related to little bitterns (Ixobrychus) and was much smaller than the St Bathans Heron (Matuku otagense) that it lived alongside.
The genus name Pikaihao is based on Māori words meaning a small fisherman. The species name bartlei honours J A (Sandy) Bartle, retired curator of birds at the Museum of New Zealand Te Papa Tongarewa.
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This tiny bittern probably lived in the reeds around Lake Manuherikia. The genus name Pikaihao is based on Māori words meaning a small fisherman. The species name honours J A (Sandy) Bartle, retired curator of birds at Te Papa.
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This Green-backed Heron from Europe is a modern descendant of Bartle's Bittern.
Canterbury Museum AV37661
St Bathans False Flamingo
This goose-sized bird, described from two fossil leg bones, was a member of an extinct group called the palaelodids. These were slender birds with long, thin legs and a long neck. Like their close relatives, flamingos, they fed in shallow water but they had a straight bill and not the distinctive bill of flamingos.
Until the fossils were found at St Bathans, the group was only known in North and South America, Europe, Egypt and Australia. Some palaeontologists believe Palaelodus could swim under water, chasing prey. But it’s more likely that they browsed for food while swimming or standing in shallow water.
Compared to its Northern Hemisphere relatives, Palaelodus aotearoa was medium-sized, slightly smaller than the older Palaelodus wilsoni from South Australia. Compared to other members of the group, the New Zealand bird had stouter legs.
This goose-sized bird was a member of an extinct group called the palaelodids. These were slender birds with long, thin legs and a long neck. They fed in shallow water. Unlike their close relative, the flamingo, they had a straight bill.
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This Greater Flamingo specimen from Africa is much larger and has a unique bill shape not found in Palaelodus.
Canterbury Museum AV39603
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This is a 3D printed facsimile of the original Palaelodus aotearoa thigh bone.
3D printed fossil scanned from the original: Museum of New Zealand Te Papa Tongarewa S051799
New Zealand Lake-wanderer
Shorebirds are a diverse group, which includes gulls and the migratory godwits that visit our shores each year from their Arctic breeding grounds. Fossils of wading birds have been found at St Bathans. These prehistoric birds had ancient and mysterious origins.
The proportions of the wing bones of the New Zealand Lake-wanderer indicate that it was a good flier and, as some of bones were from young birds, that these birds bred locally rather than being migrants from elsewhere.
This small wading bird was similar in size to a male Australian Plains-wanderer (Pedionomus torquatus) and it probably weighed between 50 and 60 grams. Features of the bones place Hakawai melvelli in a group of wading birds that includes both the Australian Plains-wanderer (Pedionomidae) and the group of South American seedsnipe (Thinocoridae).
The Plains-wanderer may be its closest relative, but the bird is sufficiently distinct that it may deserve to be placed in its own family.
The genus name is based on the mythical Hakawai of Māori legend. The species name honours New Zealand-based ornithologist David Melville for his efforts to advance shorebird conservation locally and globally.
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Although probably a good flier, some of the fossil bones found were from young birds indicating they bred locally rather than being migrants. The genus name is based on the mythical Hakawai from Māori legend.
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These tiny bones are the original fossils used to describe the New Zealand Lake-wanderer. This small wading bird was the size of a starling.
Canterbury Museum 2013.18.985, 2013.18.195
This small starling-sized wading bird foraged on the lake shore. Its bones are fairly rare in the St Bathans sediments, making it difficult to determine much about the bird’s ecology. It may have weighed 88 to 98 grams. Some of the fossils were from younger birds, indicating that the birds were not migrants but bred here.
Neilus sansomae was probably the ancestor of a group of wading birds that includes the sheathbills of the Antarctic and subantarctic islands and the Magellanic Plover of South America. Although much smaller than the two species of living sheathbill, features of the bones suggest Neilus may have been a closer relative of sheathbills than the Magellanic Plover.
The genus name is after Neilus who was, in Greek mythology, the father of Chiona. This refers to Sansom’s Plover being the ancestor of the sheathbills in the genus Chionis. Neilus comes from the Greek word meaning river valley, so it also describes the site where the fossils were found.
The species name honours Southland ornithologist Olga Sansom (1900–1989) who, along with her daughter Maida Barlow, studied shorebirds in southern Aotearoa New Zealand.
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These small wading birds foraged and likely bred around the shores of Lake Manuherikia. They are probably the ancestor of some much larger, modern wading birds including sheathbills and the Magellanic Plover of South America.
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A Black-faced Sheathbill from the subantarctic islands of the Indian Ocean is the closest living relative of Sansom's Plover.
Canterbury Museum AV12392
St Bathans Diving-petrel
Although St Bathans was a freshwater lake it was clearly not far from the sea as several marine shells and the bones of a seabird have been found in the lake.
Pelecanoides miokuaka is the oldest known member of the marine diving-petrels. The species was described from a partial upper wing bone found at St Bathans. The only other fossil diving-petrel described (the South African species P. cymatotrypetes of the Early Pliocene) is 10 to 15 million years younger.
The genus name is that of the living diving-petrels. The species name miokuaka comes from the Māori name for diving-petrels (kuaka) combined with mio that denotes it is from the Miocene.
This seabird’s species name, miokuaka, derives from the Māori name for the Common Diving-petrels found in Aotearoa New Zealand today, Kuaka. It is the oldest known member of the marine diving-petrel family.
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This is a 3D printed facsimile of the original Pelecanoides miokuaka upper wingbone next to the same bone of a living Common Diving-petrel. The St Bathans Petrel probably looked much like the Common Diving-petrel specimen.
3D printed fossil scanned from the original: Museum of New Zealand Te Papa Tongarewa S042431 Common Diving-petrel: Canterbury Museum AV23432
St Bathans Pigeon
The St Bathans Pigeon was slightly smaller than a New Zealand Pigeon (kererū). It was more closely related species in Australia and Melanesia that to the living New Zealand Pigeon.
The genus name comes from rupe, a Māori and Polynesian name for pigeons, and phaps, a Greek noun for wild pigeon. The species name taketake is from a Māori word meaning ancient or original.
The St Bathans Pigeon was smaller than today’s kererū. It is more closely related to pigeons in Australia and Melanesia than Aotearoa New Zealand’s native pigeons.
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This Topknot Pigeon from Australia is a close relative of the extinct St Bathans Pigeon.
Canterbury Museum AV38583
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This fossil leg bone is next to the same bone from a living New Zealand Pigeon (Hemigphaga novaezeelandia).
Canterbury Museum 2013.19.915
A second species of pigeon, Deliaphaps lived in Aotearoa New Zealand during the early Miocene.
More fossil material will need to be found to establish its relationships to modern birds. However, scientists believe it is most closely related to the Living Samoan Tooth-billed Pigeon (Didunculus), the giant Papuan Crowned Pigeons (Goura), the Nicobar Pigeon (Caloenas) and the extinct Dodo.
Scientists need to find more fossils of this rare pigeon before they can say with certainty which modern birds are its closest relatives, but they believe it might have been connected to the now-extinct Dodo.
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This critically endangered Samoan Tooth-billed Pigeon is related to the Zealandian Dove.
Canterbury Museum AV385455
Squawkzilla the Giant Parrot
In 2008, a pair of very large bird leg bones was discovered at St Bathans. Palaeontologists initially thought the bones were from a giant eagle, but then realised they were from the largest parrot ever found.
This one metre-high giant parrot probably couldn’t fly and although mainly a vegetarian, it may also have eaten meat. The native kea, which are parrots, are known to attack sheep and they are much smaller than this monster bird.
The palaeontologists formally named it Heracles inexpectatus, Heracles after the powerful hero of Greek mythology and inexpectatus to reflect the surprising nature of the discovery. They nicknamed it Squawkzilla. These giant parrots may have weighed as much as 7 kg, more than double that of the unusually heavy kākāpō, also a parrot.
This giant parrot, the world’s largest, probably couldn’t fly. Although mainly a vegetarian, it may have also eaten meat. The palaeontologists who discovered the bird nicknamed it Squawkzilla.
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A life-sized model of the metre-tall parrot Heracles inexpectatus, nicknamed Squawkzilla by scientists.
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Heracles inexpectatus was an ancestor of New Zealand's modern parrot species. Pictured here: South Island Kaka (Nestor m. meridionalis), Kea (Nestor notabilis) and Kākāpō (Stringops habroptilus).
Canterbury Museum AV2316, AV2529, AV 2922
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The original fossil discovered of Squawkzilla, Heracles inexpectatus, the St Bathans Giant Parrot. This fragmentary leg bone was first collected in 2008 but only recognised as belonging to a parrot in 2019.
3D print scanned from the original fossil: The Museum of New Zealand Te Papa Tongarewa NMNZ S.51083
St Bathans Tuatara
The tuatara is the sole living relative of an ancient race of lizard-like reptiles called the Rhynchocephalia that lived for at least 240 million years. From just a few fossil fragments scientists can tell that the relatives of the tuatara have long been in Aotearoa New Zealand.
The tuatara is sometimes called a living dinosaur but this isn’t factually correct. The tuatara’s ancestors lived amongst the dinosaurs but were small lizard-like reptiles. However modern birds are more closely related to the giant dinosaurs than the tuatara.
Although tuatara look like lizards, the similarity is superficial. The group has several characteristics that make it unique among reptiles. The tuatara has a third eye on the top of the head. The eye isn’t used to see but is sensitive to light and is believed to help the tuatara judge the time of day or season.
Tuatara also have two parallel rows of teeth in their upper jaw. The lower jaw fits into the gap between the rows to produce a special grinding and sawing motion to crush their prey. This feature can be seen in the fossil.
While there haven’t been enough bones found to give it a formal name, scientists are confident that it confirms relatives of the tuatara have been in Aotearoa New Zealand for at least 16 million years.
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The tuatara is the only living relative of lizard-like reptiles called the Rhynchocephalia that have existed for at least 240 million years. Just a few fossil fragments tell us that relatives of tuatara were present at St Bathans.
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This skin and skeleton are from modern tuatara which are about the same size as the St Bathans tuatara.
Canterbury Museum REP 12, REP 42
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A tiny fragment of jaw bone was the first piece found of the St Bathans tuatara.
Museum of New Zealand Te Papa Tongarewa 5.042282
Lee's Parrot is one of three smaller parrot species also found at St Bathans. These three birds were all from a single genus, Nelepsittacus.
The name recognises that these ancient parrots are the ancestors of the modern genus Nestor (the kaka and Kea). The name is derived from Greek mythology, a combination of Neleus, the father of Nestor and psittakos (Greek for parrot).
The St Bathans fossil parrots confirm the presence of the family Strigopidae in Aotearoa New Zealand for at least 20 million years. The lineage leading to the Kākāpō had apparently already diverged before this date, as there haven’t been any bones of a Kākāpō-like fossil found at St Bathans.
After Squawkzilla, Lee's Parrot is the largest and the rarest of the four parrot species described from Bathans. Lee’s Parrot was just a little smaller than the living kaka.
A relative of today’s Kea and Kākā, Lee’s Parrot was smaller than its modern cousins. It is named after geologist Dr Daphne Lee.
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Lee's Parrot was a little smaller than the kaka of today. Pictured is a South Island Kaka, Nestor m. meridionalis.
Canterbury Museum AV2316
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This is the shoulder blade of Lee’s Parrot alongside that of the living kaka.
Fossil: Canterbury Museum 2013.18.1089 Kaka bone: Canterbury Museum AV36578
The Waddling Mouse
This is an unnamed fossil species believed to be an extinct primitive land-dwelling mouse-sized mammal. It is known from just a few tiny teeth and a fragment of a limb bone.
This mammal may be a late surviving ancient species that might only be distantly related to living mammals. The discovery and publication of this find in 2007 caused a sensation.
When humans arrived in Aotearoa New Zealand, birds ruled and bats were the only land mammals. But the discovery of these fossils prove that that land mammals, other than bats, once lived in Zealandia. It suggest that our unique wildlife and plants evolved in the presence of such mammals.
When humans arrived in Aotearoa New Zealand, birds ruled. But a few tiny teeth and the fragment of a limb bone suggest a mysterious mouse-sized mammal lived at St Bathans 20 million years ago.
The Giant Burrowing Bat
Burrowing bats (Mystacinidae) are now only found in Aotearoa New Zealand but they were once found throughout Gondwana. They are unique amongst bats, as they scurry about on all fours foraging for food on the forest floor and along tree branches.
The forest around Lake Manuherikia were once home to at least four different types of bats. A giant burrowing bat, three times the size of the bats now living in Aotearoa New Zealand, was the most bizarre.
This bat, which weighed about 40 grams, was named Vulcanops jennyworthyae, after Jenny Worthy, a vital member of the palaeontology team who sorted through thousands of fossil fragments to find the hidden treasures.
The genus name recognises Vulcan, the mythological Roman god of fire, referring to New Zealand's volcanic nature, but also to the historic Vulcan Hotel at St Bathans. Burrowing bats are related to vampire bats and other bats from South America.
This bat scurried on all fours to forage among leaf litter on the forest floor. It was around three times the size of the burrowing bat species that live in Aotearoa New Zealand today. These bats are related to vampire bats and other bats from South America.
An Unnamed Swift
A small species of swift, known as a swiftlet, has been identified from several bones found at St Bathans.
Swifts are small aerial feeding birds. This one was similar in size and form to the swiftlets found in tropical southeast Asia, Indonesia, Melanesia, northern Australia and Polynesia such as this specimen. Swifts no longer breed in New Zealand, but two much larger species occasionally visit.
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Small species of swifts, known as swiftlets, are tropical, aerial feeding birds that seldom land. This fossil has not been given a species name because of the small number of bones found. Swifts no longer breed in Aotearoa New Zealand.
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A Needletail Swift from Borneo that is a similar size to the extinct St Bathans Swift.
Canterbury Museum AV39691
Livezey's Rail is one of two tiny rails found fossilised at St Bathans. Rails are a group of aquatic birds which include the Weka, Tākahe and Pūkeko. Many rail species have spread from continents to far-flung islands.
The St Bathans rail species were both tiny compared to many of today's rails. They had smaller wings and were flightless.
Livezey's rail was the more uncommon of the two species. Its genus name comes from a combination of the Latin litore, meaning shore and rallus for rail. The name refers to the fact that the fossils were mostly found in clay sediments indicating that these birds probably lived around the lake shore.
The species name acknowledges the late Bradley C Livezey (1954–2011) and his enormous contribution to understanding the evolution birds, particularly rails and the evolution of flightlessness.