Category Archives: Cetaceans

The Third King

The basilosaurids are among the fossil animals I find most fascinating. Despite the suffix, this is a group of fossil whales in a very interesting phylogenetic position; they’re floating in between the points where whales became fully aquatic and the split between toothed and baleen whales. The phylogeny of this group has been undergoing major upheavals, so those used to simplified diagrams of whale evolution may find it surprising that Basilosauridae is a diverse side-branch rather than one or two transitional species. Discussing phylogeny can turn into an unreadable multi-paragraph slog, so I’ll try something different:

In Uhen (1998), Basilosauridae was a grade between protocetids and the extant toothed and baleen whales. Basilosaurus and Dorudon were distant relatives and the poorly-known Pontogeneus was considered valid (it’s a nomen nudum today)
Uhen (1998) didn’t resolve the positions of Ambulocetidae and Remingtonocetidae, however since they were recognized as separate groups in the discussion, I showed them as such. Basiloterus was not subjected to phylogenetic analysis, but considered a member of Basilosauridae, hence the uncertain placement.
Since Uhen (1998), the clade ‘Pelagiceti’ was recognized and includes all basilosaurids, toothed and baleen whales; ‘Neoceti’ includes only the toothed and baleen whales and their mysterious relatives. Kekenodon is not a new species, but was for a time considered a baleen whale. Ocucajea is new and while classified as a basilosaurid, seems to be a closer relative of modern whales. The rest of Basilosauridae has been substantially re-structured: perhaps most notably, Dorudon and Basilosaurus are sister taxa.
This phylogeny didn’t include remingtoncetids or ambulocetids, they were added since I wanted this to be an animation (turns out it doesn’t work so well with the airbrush, huh). Basiloterus was not analyzed and its position is unknown (but it seems to be a basal basilosaurid).

Okay, those are definitely paragraphs, but at least they’re small enough to be optional. So what is… The Third King? Some of its remains were previously known as Eocetus or “Eocetus(long story) and they were classified as protocetids less derived than Babiacetus.  In 2013, Gol’din & Zvonok argued the association with Eocetus was a mistake and moved the whales into Basilosauridae under the new name Basilotritus. That group now contains three lineages characterized by elongate vertebrae and large body size: Basilosaurus (“lizard king”), Basiloterus (“another king”) and now Basilotritus (“the third king”). I really hope this tradition continues¹.

Basilotritus is known from an astounding number of remains despite having been recognized for less than a year. Basilotritus wardii is known from the Early Bartonian of the United States and Basilotritus uheni — which has vertebrae about twice as large — is known from the Late Lutetian to Late Bartonian of Ukraine (Gol’din & Zvonok 2013). There are additional “Basilotritus sp.” from Germany and the Ukraine and in Peru there is a comparatively small species with moderately elongate vertebrae that appears to be a related genus (Gol’din & Zvonok 2013). It’s name had better start with Basil

Basilotritus sp. lumbar vertebrae and neural arch. From Gol’din et al. (2014)

In addition to the large size and elongate vertebra, Basilotritus has two rather unusual diagnostic traits: vertebrae with a pock-marked texture and layered bony tissue on the neural spines (Gol’din & Zvonok 2013). The pock marks are the openings of vascular channels and are hypothesized to be related to the long-term growth of considerable bony tissue; the layers of bone are also apparently a result of this (Gol’din & Zvonok 2013). Basilotritus then has a condition known as pachyostosis, which could allow it to be a good, long-distance swimmer at the expensive of speed and maneuverability (Gol’din & Zvonok 2013). Pachyostosis is present in other basilosaurids, but apparently does not involve the vertebrae (Gol’din & Zvonok 2013). 

There seems to have been something very strange happening with the growth and maturation of BasilotritusThe Basilotritus sp. pictured above has 5 growth layer groups — likely indicating an age of 5 years — and yet has unfused epiphyses on its cervical vertebrae, something that normally happens very early in the life of a whale (Gol’din et al. 2014). Gol’din et al. (2014) consider this a sign of paedomorphosis (along with the pachyostosis), although they are uncertain if Basilotritus rapidly reached a large size but didn’t reach skeletal maturity until later (like a baleen whale) or if it continued growing for nearly a couple decades (like an Orca). 

It’s astounding that cetaceans reached huge sizes so early in their history. I suspect that basilosaurids “experimented” with different growth strategies for reaching huge sizes and exploiting new niches. Despite their apparently unusual growth strategy, the Basilotritus species converged on some Neoceti in regards to the number of lumbars (11–13, depending on species) and the elongation occurring in the posterior thoracics and lumbars (Gol’din & Zvonok 2013). In comparison, the huge Cynthiacetus was strange (non-elongate vertebrae, very numerous thoracics) and the leviathanic Basilosaurus was crazy weird (extreme elongation, numerous vertebrae, lumbar-like thoracics and caudals).

From Gol’din et al. (2014)

There’s more to Basilotritus than vertebrae; parts of ribs, innominate bones, sternum, scapula, hyoid, tympanic bulla and skull have been found (Gol’din & Zvonok 2013); but perhaps the most interesting are the teeth. This Basilotritus sp. from Ukraine has severely worn teeth, and in one molar the entire crown is almost worn off (Gol’din et al. 2014). This is the same individual as the previous picture, so it managed to do this in only 5 years, some of which it presumably spent nursing. A similar amount of wear occurs in Orcas that prey heavily on sharks, and it likely wasn’t a coincidence that this specimen of Basilotritus sp. was found with numerous shark teeth (Gol’din et al. 2014). Of course, it probably shouldn’t be assumed that all Basilotritus fed heavily on sharks, and perhaps like Orcas it was only practiced by one small sub-population for a small period of time.

So… fossil whales never cease to amaze. I can’t wait until this post is laughably outdated in a couple of years.


Gol’din, P. & Zvonok, E. (2013) Basilotritus uheni, a New Cetacean (Cetacea, Basilosauridae) from the Late Middle Eocene of Eastern Europe. Journal of Paleontology 87(2) 254–268.

Gol’din, P. et al. (2014) Basilotritus (Cetacea: Pelagiceti) from the Eocene of Nagornoye (Ukraine): New data on anatomy,ontogeny and feeding of early basilosaurids. Comptes Rendus Palevol. Doi : 10.1016/j.crpv.2013.11.002

Uhen, M. (1998) Middle to late Eocene basilosaurines and dorudontines. IN: The Emergence of Whales


¹ Basilosaurus drazindai is presently known from only one vertebrae with several significant differences from other Basilosaurus species as well as Basilotritus (Gol’din et al. 2013). Considering its age and the apparent close relationship between Basilosaurus and Dorudon, I think it’s very likely to be something… else. Other big, elongate vertebrae have been named “Platyosphys paulsonii“, “Platyosphys einori” and “Platyosphys sp.”, however they’re all lost or in poor condition and now considered nomen dubium (Gol’din et al. 2013). They could be members of the other Basil– lineages.

Remembering How to Draw Dolphins

I’m fascinated by erroneous beliefs — hence my coverage of cryptozoology — and I’ve become increasingly curious about why animals in old depictions are usually “wrong”. Not being an art critic or anthropologist, I’m baffled why people would illustrate animals in a way other than as accurately as possible. It appears my culture of viewing animals from a literal, scientific perspective is a quite recent phenomenon in human history.

From Masseti (2008)

This Late Helladic I blade from ~1500 BC unambiguously shows a dolphin, which has been interpreted to show a Striped Dolphin (Masseti 2008). I’m not really convinced the curved lines drawn on the figure represent the markings of that species¹ and I wonder if they could represent movement or waves. Other fairly realistic dolphins are seen in art from the Bronze Age (Fresco at Knossos) and Classical antiquity (youth playing the flute and riding a dolphinvarious coins); however, some depictions from the ancient world are quite fanciful.

From Wikipedia Commons

This figurine — from 330–310 BC Eretria, if Wikipedia is to be trusted — is still recognizably dolphin-like, but the body is unusually long and bendy (even the rostrum is curved) and the replication of fins (and… counter-dorsal fins?) is really curious. I wonder if, perhaps like the wavy patterns on the first example, this is an attempt to capture movement in a static work of art. Say, shouldn’t there be a cryptozoologist citing this as undeniable proof of a Rhinoceros dolphin“? I’ll have to discuss the bewildering phenomenon of people taking these obviously stylized artworks literally another time.

From Wikipedia Commons

In this mosaic of Eros riding a dolphin, the mount is so stylized it would be hard to tell it’s supposed to be a dolphin at all if there weren’t other depictions of the same scene. I would have guessed that this was a mythological creature based on a dolphin associated solely with deities, but several similar creatures are depicted independent of any gods. This particularly extreme style of depicting dolphins was surprisingly influential², as I’ll discuss later.

From GKS 1633 4º: Bestiarius

This 15th Century depiction of a “Delphinus” from a bestiary shares nothing with the older depictions aside from its name and aquatic nature. Other illustrations documented by the excellent website, The Medieval Bestiary, show dolphins as various generic fish. Van Duzer (2013) shows additional illustrations depicting dolphins as generic fish with human faces, but apex of illustrative eccentricity seems to have been reached here. Dolphins are most assuredly not blank-faced merfolk with either eyes or a mouth in their chests. So what the hell happened? According to Montagu (1962), knowledge about dolphins was almost completely lost at some point; it seems the only information remembered was their name and aquatic nature. Romero (2012) essentially concluded that Medieval people were backwards idiots; however, the approach of bestiaries seems dramatically different from natural history and I can’t help but wonder if there are illustrations from other sources depicting more natural dolphins, perhaps under different local names.

From the ‘Novus orbis regionum ac insularum veteribus incognitorarum’

This 16th Century illustration looks nothing like works from the Medieval era and was inspired by Classical dolphins (Van Duzer 2013). These clearly look related to the type of dolphin used as Eros’ mount and they’re very well-rendered, but it’s still not exactly a naturalistic depiction of cetaceans.

From Egerton (2003)

Pierre Belon‘s 1551 is almost a contemporary of the map-monsters above, yet its style is remarkably modern. Belon actually bothered to dissect dolphins and noted anatomical structures such as hindlimbs, lungs, milk glands and hairs, yet failed to connect them to terrestrial mammals (Romero 2012). Monstrous depictions of cetaceans continued for long after Belon’s work, but this seems to be a good stopping point.


Egerton, F. (2003) A History of the Ecological Sciences, Part 11: Emergence of Vertebrate Zoology During the 1500s. Bulletin of the Ecological Society of America 84(4) 206–212. Available.

Masseti, M. (2008) The Most Ancient Explorations of the Mediterranean. Proceedings of the California Academy of Sciences 59(1) 1–18. Available.

Montagu, A. (1962) The History of the Dolphin IN: The Dolphin In History.

Romero, A. (2012) When Whales Became Mammals: The Scientific Journey of Cetaceans From Fish to Mammals in the History of Science. IN: New Approaches to the Study of Marine Mammals.

Van Duzer (2013) Sea Monsters on Medieval and Renaissance Maps.

The websites Strange Science and The Medieval Bestiary provided invaluable leads for writing this article.


¹ Aristotle apparently conflated Striped Dolphins with Bottlenose Dolphins and Short-Beaked Common Dolphins (Romero 2012), so it could be possible the ancient Greeks also lumped the familiar species of dolphins.

² It appears this creature or a similar one provided the model for the face of my favorite monster, the Cetacean Centipede/Scolopendre Cetacee.