For archaeocete whales, toothed baleen whales, and a review of the mid-Cenozoic stratigraphy of New Zealand, see part 1. For baleen-bearing baleen whales, see part 2.
Baleen whales are arguably more common in the Oligocene of New Zealand than anywhere else on the planet - as detailed in the previous entry, at least half of the world's chaeomysticetes - but it is probably more famous for its fossil dolphins, which were Ewan Fordyce's true passion. Now, I am going to cheat a little bit, and include some early Miocene fossils here as they are of similar evolutionary grade and quite central to the story of dolphin paleontology down under.
There were numerous isolated finds made quite early on consisting of partial teeth, or sets of associated teeth in jaw fragments - early discoveries were made in the late 19th century when collecting methods were not yet refined, certain fossils consisted of teeth plucked out of outcrops or skull chunks recovered during quarrying. If I remember right, Ewan described the first 'modern' excavation of a fossil cetacean in New Zealand with anything resembling a plaster jacket to have been the Tokarahia lophocephalus excavation by Brian J. Marples in 1942.
Some of the teeth in blocks of limestone from Milburn and Clarendon quarries in central Otago, from Benham (1938), originally assigned to Lophocephalus parki, and then later named Squalodon andrewi.
"Squalodon" andrewi is one of the oldest named odontocetes from New Zealand, and like the naming of the genus Mauicetus, it stemmed from the misidentification of a chimaeric association of fossils by Benham (1937) when he named Lophocephalus parki as an archaeocete. If you recall from part 1, after some correspondence with Remington Kellogg, Benham came to accept that the holotype braincase fragment was from a Parietobalaena-like mysticete. He renamed Mauicetus parki, given that the genus name Lophocephalus was preoccupied by a beetle. He had, however, also assigned some teeth to "Lophocephalus", but now realized they were not from Mauicetus parki. He designated these as Squalodon andrewi - although none of the specimens likely actually represent Squalodon, which has been badly mistreated as a wastebasket taxon. "Squalodon" andrewi consisted of three tooth-bearing jaw fragments in limestone blocks, all that was salvaged from squalodontid skulls or mandibles from the Milburn Limestone of South Otago in the vicinity of Clarendon, just a few km northeast of Milburn. The holotype is a single tooth with double roots, and the remaining specimens appear to represent several different odontocetes. Not much further can be said about "Squalodon" andrewi. Ewan excavated a beautiful skull of a squalodontid from Milburn Quarry, the "Milburn" squalodontid, with rather similar teeth to one of Benham's (1937) specimens. All of the Milburn/Clarendon material share relatively highly rugose enamel in comparison to true Miocene Squalodon from the North Atlantic.
Perhaps the most famous image of the Earthquakes squalodontid, with preparator Andrew Grebneff examining the teeth. This photo no longer appears online in full resolution. Photo by Ewan Fordyce.
In the late 1980s, Ewan and colleagues excavated a rather large Squalodon-like skull from the Otekaike Limestone at the Earthquakes - this specimen has since been nicknamed the "Earthquakes squalodontid". Whether it's a true squalodontid or not is a different issue, but it is a rather large skull (nearly 1 m long) with a long, cylindrical rostrum, and a much greater degree of telescoping of the skull than Ankylorhiza. In many regards it is superficially similar to Phoberodon arctirostris, a Squalodon-like odontocete from the lower Miocene of Argentina. It pains me to write that this specimen has not yet been described, and was one of Ewan's unfinished legacy projects. He cared very deeply about the squalodontids, frequently joking that he might have time to work on them after retirement.
The lower Miocene Caversham Sandstone at Tunnel Beach, south of Dunedin. Photo by me.
The first truly significant fossil odontocete from the mid-Cenozoic of New Zealand did not originate from the Oligocene units but was collected from the Caversham Sandstone, earliest Miocene in age. The Caversham Sandstone forms incredibly scenic coastal cliffs south of Dunedin (which I have painted in watercolors and acrylic on canvas) as well as north of Dunedin in the cliffs near Waikouaiti. In 1902, Mr. Augustus Hamilton collected a block containing a large partial skull from Caversham Quarry in the southwestern part of town - Caversham is a neighborhood sandwiched between the coastal neighborhood of St. Clair (where we would occasionally go to the beach) and central Dunedin. I've no idea where the quarry is today, if any of it remains, but my fellow student Gabriel Aguirre-Fernandez - studying NZ fossil kentriodontid dolphins from this and other Miocene units - had identified at least one possible skull awaiting collection in a roadcut nearby, as well as another skull nearly 20 feet up the cliff at Tunnel Beach.
The holotype skull and one of the teeth of "Prosqualodon" hamiltoni, a Phoberodon-like squalodontid grade dolphin from the Caversham Sandstone (earliest Miocene).
Mr. Hamilton's skull was quite large - 34 cm wide, around the size of a pilot whale - and preserves a virtually complete braincase and the posterior third of the rostrum. There are a handful of teeth, with double-rooted teeth bearing longitudinal ridges on the enamel and some serrations. Professor Benham conservatively named this species Prosqualodon hamiltoni in a 1936 paper - referring it to the same genus as Prosqualodon australis named by Lydekker 50 years prior from the lower Miocene of Patagonia, and the more recently named Prosqualodon davidis from lowermost Miocene rocks of Tasmania across the Tasman. Benham was well-aware of the differences between the New Zealand skull and fossils of P. davidis and P. australis, including the dentition: he clearly noted how the teeth were simpler than those of P. davidis and P. australis, which have more rugose enamel with "reticulated ridges", and he also pointed out that true Prosqualodon spp. have accessory cusps but that these are absent in P. hamiltoni.
Benham did not provide much of a description of the skull, but the following observations can be summarized in a modern context. It has a rounded occipital shield and a wide vertex, with a small rectangular 'table' between the occipital bone and the nasals - roughly similar to Squalodon, Waipatia (see below), and many dolphins on the odontocete stem as well as some early crown odontocetes. The vertex is positioned anteriorly as are the orbits, and the temporal fossae - the spaces for the jaw-closing temporalis muscles - are cavernous, and visible in dorsal view. The premaxillae are relatively wide, and so is the mesorostral groove - it is nearly rectangular in outline. The sum of these observations indicates to me that P. hamiltoni is something similar to Ankylorhiza from South Carolina, but very likely something more 'primitive' than Phoberodon, Squalodon, or Prosqualodon. In particular, P. hamiltoni really looks like "Genus Y" - the undescribed species of Ankylorhiza represented by ChM PV 2764 at the Charleston Museum, right down to the teeth. Ewan considered it to be a squalodontid in his 1994 paper on Waipatia, and it decidedly does not closely resemble Prosqualodon davidis or P. australis - especially in lacking the short rostrum that is unique to true species of Prosqualodon. Little had been written on this specimen in the past 90 years, until Maximilian Gaetan and colleagues (2025) published a new paper on Prosqualodon australis. They coded P. hamiltoni into a phylogenetic matrix for the first time, and unsurprisingly this taxon plotted out amongst the waipatiids, specifically in a weakly supported clade formed with the much, much smaller Nihohae and Nihoroa. However, the analysis included only Ankylorhiza tiedemani, which lacks earbone codings - and it's likely that these relationships might change pending inclusion of more complete specimens like Ankylorhiza sp., ChM PV 2764, which has been coded in many previous analyses. Regardless, this is pretty solid evidence that "Prosqualodon" hamiltoni is something else and not related to Prosqualodon australis. If it IS a giant waipatiid and not something like a squalodontid (which I strongly doubt) or something close to Ankylorhiza, it would imply repeated evolution of large bodied odontocetes in the southern Ocean (at least 3-4 lineages including "P." hamiltoni, the Earthquakes and Milburn squalodontids, and of course Prosqualodon itself).
The teeth of Tangaroasaurus kakanuiensis, another Phoberodon-like squalodontid dolphin from the lower Miocene - probably collected from the Gee Greensand. From Benham (1935), who initially identified this as an ichthyosaur.
In 1935, Benham reported an isolated tooth of a large dolphin from near Kakanui and named it Tangaroasaurus kakanuiensis, incorrectly assuming at the time that the specimen represented a marine reptile, and specifically an ichthyosaur. Curiously, one of these specimens is quite clearly a double-rooted tooth that's been broken down the middle. Further curious is that earlier reports indicated that the specimen was Miocene and associated with fossil whale remains - acknowledged by Benham. In his review of California mosasaurs, Camp (1942) cited communications with Remington Kellogg who considered the fossil to be a squalodontid; Brian Marples (1949) and Ewan Fordyce later agreed with squalodontid affinities. Mandible fragments illustrated by Benham (1935) are now lost. In 2013, Ewan took us on a field trip to the exact spot where it was collected, an exposure of the lower Miocene Gee Greensand. Ewan suggested, in conversation to me on a couple of field trips, that it perhaps was synonymous with Phoberodon from coeval rocks in Argentina.
Another specimen, and the last named by Professor Benham, was named Microcetus hectori in 1936. Microcetus ambiguus is a set of associated teeth from the Oligocene of Germany, named earlier. At the time, the referral seemed reasonable. Microcetus hectori was chiefly named based on a small mandible (misidentified by Benham as a maxilla; it is admittedly crushed into a triangular shape, resembling a maxilla) fragment with five well-preserved teeth in it, along with parts of eight additional teeth, all collected from the Otekaike Limestone somewhere in the Waitaki Valley (the original precise locality has been lost) - but is known to have been collected by early NZ geologist Alexander McKay in summer of 1881, making this one of the oldest fossil cetacean discoveries in the country. The mandible itself is quite cute - I've held it - and it's got these tiny little teeth in it that are quite distinctive: they have a ridge with zig-zag shaped 'crenulations' on the lingual (tongue) side of the teeth - called a cingulum - and a poorly developed labial (lip side) cingulum that consists of a few vertical ridges; the teeth are otherwise smooth closer to the crown. The teeth are quite tall, lack mesial (anterior) accessory cusps, and have only two distal (posterior) accessory cusps. Later study by Ewan Fordyce during his doctoral program revealed unprepared blocks of limestone collected along with the mandible fragment reported by Benham, hiding in the collections of the national museum (Te Papa). Among these blocks was quite a bit of a braincase, which was then prepared further by Yoshi Tanaka during his Ph.D. (Yoshi was my office mate, and so I had a front seat to much of the research covered in this post!). The skull revealed a number of close similarities with Waipatia maerewhenua (see below), leading Tanaka and Fordyce (2016) to reassign the species to Waipatia as Waipatia hectori.
The original illustration of "Prosqualodon" marplesi, from Dickson (1964) - it's got all the hallmark features illustrated. Later named as the new genus Otekaikea by Tanaka and Fordyce (2014).
The holotype skull of Otekaikea marplesi in dorsal view, from Tanaka and Fordyce (2014).
The earbones (periotic and tympanic bulla) of Otekaikea marplesi. From Tanaka and Fordyce (2014).
Otago Geology Master's student M.R. Dickson (who I met in 2014 or so) continued the trend of assigning fossil dolphins to Prosqualodon when he named Prosqualodon marplesi from the "Trig Z" locality in the Otekaike Limestone near Duntroon. This specimen consists of a well-preserved braincase lacking the rostrum, but preserving a partial mandible, atlas and axis vertebrae, a beautiful scapula, and other postcrania. The skull is superficially similar to Squalodon in its general morphology: there is no intertemporal constriction, meaning the skull is quite telescoped. The posterior end of each premaxilla is split into a swallowtail shape - called the premaxillary cleft by later workers. The vertex is formed by the frontal and nasals, and is table-shaped and somewhat squared; the nasals are small and rectangular. Superficially similar to some platanistoid dolphins like the Squalodelphinidae, the 'postglenoid process' - part of the squamosal bone that forms the skull half of the jaw joint - tapers ventrally, rather than having a rectangular shape as in Waipatia (see below). The periotic bone is generally similar to Squalodon in certain features (moreso than to squalodelphinids). Later, this species was reassigned to Notocetus by Fordyce (1994), and then eventually recognized as a waipatiid dolphin (see below) and named its own genus as Otekaikea marplesi by Tanaka and Fordyce (2014).
The holotype skull and mandible of Waipatia maerewhenua, from Fordyce (1994).
More images of the skull of Waipatia maerewhenua, along with the tympanic bulla. From Fordyce (1994).
In 1989, Ewan was prospecting with preparator Andrew Grebneff and came across the tip of a small cetacean snout sticking out of the Otekaike Limestone in the vicinity of Waipati, on Mike Harvey's farm (this was, by the way, very close to the type localities of the later-described mysticetes Tohoraata raekohao and Whakakai wapaiti described by C-H Tsai and yours truly). They excavated the specimen, and brought it back to the Otago lab. The skull resembled shark-toothed dolphins in some ways, but had relatively small teeth, and was much smaller - and older - than any species of Squalodon. Ewan set about writing the specimen up, eventually published in the Proceedings of the San Diego Society of Natural History, in a special volume honoring Smithsonian paleontologist Frank Whitmore. He named it Waipatia maerewhenua - after the locality, Waipati, and the nearest river, the Maerewhenua river. This was the first of many New Zealand fossil cetaceans named in the Maori language - and while most American speakers I've heard have little trouble pronouncing the genus, I'm highly, deeply, genuinely amused every time someone tries to pronounce the species name around me, knowing I know how to do it, saying "mar-uh... uh..." and trailing off into an intentionally quiet noncomittal utterance as. I always let folks try and pronounce it on their own before offering the correct version. For a brief guide to Maori pronunciation, check out the first post in this series.
Waipatia is a very interesting dolphin, and it is clearly the same evolutionary grade as "Prosqualodon" marplesi, "Microcetus" hectori (which, as discussed above, was recombined as Waipatia hectori more recently). Most critically, Ewan Fordyce recognized that this was the first well-preserved early odontocete from the Oligocene that had a nearly complete skull, well-preserved earbones removed from the skull, nearly complete mandible, and most of the dentition. In this regard, it's a keystone specimen for the study of early odontocetes. Further, and perhaps more critically, the anatomy of Waipatia is quite revealing - first, it clearly indicated that a whole new family, the Waipatiidae, needed to be named in order to contain it. Waipatia is similar in its overall grade of evolution to Squalodon, and even has some similar earbone features, but is much smaller, with smaller teeth. Like Squalodon, it has some tusk-like incisors, double-rooted teeth, heterodonty (the teeth dramatically change shape from front to back), polydonty (more than 11 teeth per quadrant, the primitive number for placental mammals). The earbones had some features that Fordyce considered grouping Waipatia with platanistoids* (a controversial group altogether). These include a spine on the anterior end of the tympanic bulla, and a little ridge on the posterolateral side of the periotic called the articular process. In modern toothed whales, this process is only observed in Platanista gangetica, the Ganges River dolphin**. Ewan conducted the first computer-run cladistic analysis of odontocete relationships (and quite possibly of cetaceans in general) and did recover Waipatia within the Platanistoidea.
*There are two historical concepts of the Platanistoidea: 1) the Platanistoidea of G.G. Simpson, in which the group is formed only by modern river dolphins - this has been widely discounted for about 30 years now as none of these dolphins are related to each other; 2) the Platanistoidea of C. de Muizon, including the modern species Platanista and everything more closely related to it. This has in the past included the Waipatiidae, Squalodontidae, Allodelphinidae, and the Squalodelphinidae; it seems however that the waipatiids and squalodontids likely do not fall inside the odontocete crown group, or within this more modern concept of the Platanistoidea.
**Over the years, many other early odontocetes have been found with the articular process, and having one seems to have been the primitive condition for Odontoceti, rather than indicating platanistoid relationships. Honestly, I could do an entire blog post about the Platanistoidea.
Other possible waipatiid dolphins - from Fordyce (1994).
The discovery of Waipatia had some further implications for dolphin evolution. The skull shows some evidence of cranial asymmetry - it's subtle, but there are some features worth noting: 1) the base of the rostrum has a flared crest on the right maxilla, 2) the left premaxilla extends further posterior than the right; 3) the nasals and nasofrontal suture are rotated in dorsal view so that the right nasal is shifted further anterior; and 4) the exact positions of some of the foramina in the facial region are not precisely symmetrical, in number or configuration. Altogether, this is suggestive of asymmetrical facial muscles involved in echolocation. Further evidence that Fordyce (1994) outlined includes the presence of premaxillary sac fossae, which are present throughout modern toothed whales (all of which can echolocate); these structures house the muscles that retract the nasal plugs, which seal off the nasal passages during diving and may have a role in sound generation. Though not outlined clearly by Fordyce, Waipatia has a concave facial plane, widely considered a bony correlate of the melon in cetaceans - a soft tissue structure intimately linked with echolocation. Ewan also concluded that several other odontocetes were candidates for inclusion in the Waipatiidae, given that these species are smaller than Squalodon and of similar Oligocene age. The first is of course Microcetus ambiguus from the Oligocene of Austria, to which Benham (1935) originally referred Microcetus hectori. The teeth are roughly similar, but suggest confamilial rather than congeneric affinities. Microcetus sharkovi is a small Waipatia-like dolphin reported from Oligocene rocks of Kazakhstan by Georgian paleocetologist Guram Mchedlidze (isolated from the west within the Soviet Union during the entirety of his career), and it has small heterodont teeth, unlike Squalodon. Another small beast named by Mchedlidze is Sulakocetus dagestanicus from the Caucasus Peninsula, similarly having small heterodont teeth and small size like Waipatia (and differing from squalodontids), and very likely belongs in this group. The last is another waipatiid behind the iron curtain, Sachalinocetus cholmicus, named by Irina Dubrovo from Sakhalin Island (between Japan and the Kamchatka Peninsula) - also from the western Pacific, but from lowermost Miocene deposits. Sachalinocetus has a much more elevated skull, resembling Ediscetus from South Carolina.
The holotype skull of Papahu taitapu in dorsal view, from Aguirre-Fernandez and Fordyce (2014).
The holotype skull of Papahu taitapu in ventral view, from Aguirre-Fernandez and Fordyce (2014).
The holotype skull (and mandible) of Papahu taitapu in anterior and lateral view, from Aguirre-Fernandez and Fordyce (2014).
The holotype periotic of Papahu taitapu, from Aguirre-Fernandez and Fordyce (2014).
A little skull that Ewan and preparator Andrew Grebneff collected in 1987 from the lowermost Miocene Kaipuke Siltstone at the north end of the South Island was the subject of one of the major chapters in Gabriel Aguirre-Fernandez's Ph.D. thesis, and he got it published in 2014 (Aguirre-Fernandez and Fordyce, 2014). This little skull was initially thought to be one of the world's oldest known delphinoids, and a possible kentriodontid - however, careful study and revised codings during his Ph.D. revealed that it's actually a stem odontocete, and similar in many regards to waipatiid-grade dolphins. The skull was named Papahu taitapu, Maori for dolphin and 'northwest coast' (Te Tai Tapu). The skull is rather small, only 18 cm wide, and the entire specimen as preserved is only 32 cm long, and was probably around 37-40 cm long when complete - it's missing just the tip of the rostrum. In general, however, it doesn't really closely resemble kentriodontids; the vertex is quite primitive looking with a large flat table of the frontal exposed, like Waipatia, and the posterior end of the premaxilla is split with a cleft and two plates - just like Waipatia and Otekaikea spp. (see below). However, perhaps critical to the initial misattribution, was the fact that the tooth sockets all appear to be single-rooted.* One feature that was critically lacking that resulted in the recognition of this specimen as being clearly outside the Delphinioidea (and therefore Kentriodontidae as well) was the lack of an infraorbital extension of the pterygoid sinus fossa - this is a bony trench or fissure that connects with the pterygoid sinus fossa just in front of the earbones, and houses air and blood-filled sinuses that serve to both help acoustically isolate the earbones during underwater hearing and function as venous drainage during diving. It's pretty complicated, so I'll leave it at that for now - the key takeaway is that this fossa/sinus system is restricted to the auditory region in Papahu, just like Waipatia and Squalodon. However, it does share a feature with Delphinida (a big clade in odontocetes that basically includes the Delphinoidea and a couple of South American river dolphins, along with many delphinoid-like fossils) - a lateral lamina of the palatine (though this is sporadically found in a couple of other stem odontocetes, like Prosqualodon davidis).
*However, it is possible that the teeth were in fact double rooted, but crowded, so no pairing of the alveoli is evident. It's a slim chance, but we won't really know until a specimen of Papahu with teeth is found. Given that many heterodont dolphins diverge after Papahu on virtually all cladistic analyses, it is not out of the question (and perhaps even likely, in my opinion).
Most of the Otago Lab at the time that Papahu taitapu was named by Gabriel Aguirre-Fernandez and Ewan. From left to right: Carolina Loch, Yoshi Tanaka, Gabriel, Felix Marx, yours truly, and of course, Ewan Fordyce. Photo courtesy Otago Daily Times.
The earbones of ZMT 73, a specimen identified as cf. Papahu, from Tanaka and Fordyce (2016).
Two years later, Yoshi published on a fragmentary specimen (Tanaka and Fordyce, 2016) that Ewan had studied in his thesis, ZMT 73, which they identified as cf. Papahu. Critically, this specimen had a more complete periotic and bulla, revealing some additional features not evident in the juvenile holotype specimen. Improved coding and sampling pulled both Papahu taxa from the stem Odontoceti (as in Aguirre-Fernandez and Fordyce, 2014) or the Platanistoidea (as in Tanaka and Fordyce, 2015) into a clade with the Ziphiidae (beaked whales), Eurhinodelphinidae ("swordfish dolphins"), and the Delphinida. At face value, there are many broad similarities with early Miocene dolphins like eurhinodelphinids, especially within the periotic. We need more studies of early Miocene odontocetes with crazy long snouts, and I wouldn't be surprised if Papahu fits in right there; its periotic looks like a swollen eurhino periotic, and as Tanaka and Fordyce (2016) point out, it has a very similar looking bulla to ziphiids and eurhinos.
The holotype skull and mandible of Otekaikea huata in lateral and dorsal view. From Tanaka and Fordyce (2015).
The holotype incisor tusks and other teeth of Otekaikea huata. From Tanaka and Fordyce (2015).
The holotype periotic (and bulla fragment) of Otekaikea huata. From Tanaka and Fordyce (2015).
After Tanaka and Fordyce (2014) redescribed "Prosqualodon" marplesi and named the new genus Otekaikea, they published a followup paper a year later (Tanaka and Fordyce, 2015), naming a more spectacularly preserved specimen from the Oteikaike Limestone at Hakataramea quarry as Otekaikea huata. Otekaikea huata has more of the rostrum preserved, along with more postcrania: a similar number of vertebrae, some ribs, a sternum, and a nearly complete forelimb including scapula, humerus, radius, and ulna. The rostrum is quite poorly preserved - none of the elements quite connect with each other and they are all highly bioeroded, but it was clear from the premaxillae that the rostrum was quite long, perhaps 2.5 times the length of the braincase. The skull is slightly wider than Waipatia - 26 v. 24 cm - but is quite a bit longer, nearly 80 cm, as opposed to ~60-65 cm for Waipatia. The incisor tusk is surprisingly large, being at least 20 cm long, 1.5 cm in diameter, and the crown has been completely worn away, perhaps down to the gumline; the estimated total length, including the crown, is 28 cm (!). The anteriormost tooth is not preserved in Waipatia, but it was likely not quite so large; in Otekaikea marplesi, the equivalent tooth is quite a bit smaller. The cheek teeth are somewhat more homodont than in Waipatia and have fewer denticles. The facial plane of the skull is more deeply concave, and the facial region in general is somewhat more asymmetrical than in Waipatia - this further suggests that Otekaikea (and waipatiids in general) was capable of echolocation. Tanaka and Fordyce (2014) ran a phylogenetic analysis of odontocetes, which was modified from a matrix by Mizuki Murakami focused on delphinoids; they added 16 characters from other studies, for a total of 278 characters coded for 76 modern and extinct species. In their analysis, they recovered a waipatiid clade including Waipatia and Otekaikea, along with OU 22125, which would later be named Awamokoa tokarahi (see below). This monophyletic Waipatiidae was found to be sister to the Squalodelphinidae and Platanistidae, and is one of the few recent studies to have found anything beyond platanistids and squalodelphinids recovered in this clade. In one of their two analyses, they also recovered squalodontids as platanistoids.
The holotype left mandible of Awamokoa tokarahi. From Tanaka and Fordyce (2016).
A fragmentary skeleton from the Kokoamu Greensand at Awamoko Stream near Tokarahi was named Awamokoa tokarahi by Tanaka and Fordyce (2016). This species is the oldest named odontocete from New Zealand, and one of the only ones from the Kokoamu Greensand - it's slightly older than Waipatia, which is from low in the Otekaike Limestone. Awamokoa is known from the edge of the right side of the braincase, and includes a well-preserved auditory region of the skull along with the right periotic, both tympanic bullae, a partial left mandible, a handful of teeth, cervical and thoracic vertebrae, a partial forelimb, and ribs. Awamokoa is generally similar to Waipatia and Otekaikea in most regards, but has a long temporal fossa suggesting that it had a slower but more powerful bite than later "platanistoids", which had longer rostra and smaller teeth, suggestive of more rapid snapping. Though no tusks are known, there are some long-rooted anterior teeth consistent with having procumbent teeth up at the tips of the jaws.
The fragmentary skull of aff. Prosqualodon davidis from the Mt. Harris Formation of New Zealand with an outline of the holotype from Tasmania. From Tanaka et al. (2022).
The fragmentary skull of aff. Prosqualodon davidis from the Mt. Harris Formation of New Zealand. From Tanaka et al. (2022).
Teeth belonging to the New Zealand specimen of aff. Prosqualodon davidis. From Tanaka et al. (2022).
One of the only published specimens from the Mt. Harris Formation is a partial skull found in siltstone exposures in the wave-cut platform at Awamoa Beach in 2001, and featured prominently in former Otago student Megan Ortega's thesis. The specimen was finally published by Yoshi Tanaka, Megan Ortega, and Ewan in 2022, and identified as cf. Prosqualodon davidis - an extension of the range of this species from Australia to New Zealand. The skull is perhaps the least spectacular of any in this post - but it is nonetheless quite important owing to its age - there are not a whole lot of early Miocene fossil dolphins from New Zealand. The skull must have been pretty severely eroded by the time of discover; parts are reasonably well preserved. Critically, there are two teeth preserved that rather closely match the teeth of the holotype skull of Prosqualodon davidis from Tasmania (now lost, unfortuna
