The Cladistics of DOOM

On 10 December 2__3, the UAC bases Phobos and Deimos were overrun by unidentified combatants. Footage of the events were captured by a Spacemarine operating the T.A.G.G.A.R.T. combat system, however, due to the several metric tonnes of weapons and munitions, there was only room for a 256 color 480×360 Steadicam. Despite the limited resolution, the bright, colorful graphics captured numerous remarkable morphological and behavioral traits of the “alien” or “demon” invaders. Type specimens were never collected from the now-abandoned bases, and as such, this footage, along with a few cultural depictions, remains the only evidence of the invaders.

55 morphological traits were recorded and included head/torso fusion, horn morphology, exposed brains, paired posterior sphincters, flight et cetera. There were 11 additional traits detailing behavior, 39 relating to sounds and 44 detailing toughness, size, reaction time and estimated mass. In all, there were 149 traits (32 multi-state) and 11 apparent taxa. The program MrBayes was used to analyze the Standard data and was run for 1,000,000 generation, finishing with an average stdev of split freq of 0.002921 and a TL PSRF of 1.000. The most parsimonious tree is as follows:

DOOM1

Perhaps the most surprising clade (bootstrap value of 100) is that consisting of the seemingly-disparate “Lost Soul”, “Cacodemon” and “Spiderdemon”. The latter two share the highly unusual trait of head/body fusion, whereas the “Soul” lacks any evidence of a body at all; its presence in the group could be the result of long-branch attraction. It is also notable that the “Spiderdemon” has extensive cybernetic modifications, so knowledge of its original state (if any) could significantly change its placement. One clade of horned, digitigrade “demons” (“Cyberdemon”, “Baron of Hell”, “Demon” and “Spectre”) receiving surprisingly low support (bootstrap value of 63) for unknown reasons. Also curious is that the most basal “demon”, the “Imp” is also the most humanoid, raising the question of what sort of relationship these aliens have with Homo sapiens.

A second incursion event occurred on 30 September 2––4, this time on various Earth locations. Steadicam footage was of similar quality to the first event and managed to record 7 additional taxa. The number of traits was expanded to 201, with 33 being multi-state. MrBayes was once again used to analyze the Standard data and run for 1,000,000 generations, ending with an average stdev of split freq of 0.006850 and TL PSRF of 1.000.

DOOM2

Interestingly, the position of the “Imps” is now closer to the horned, digitigrade “demons”, with two humanoid taxa (“Arch-Vile”, “Mancubus”) now occupying and unresolved position between the “former” humans and other demons. Interestingly, one taxa (“Revenant”) with some human-like traits (especially clothing and weapon use) is not a member of this polytomy. Also interesting is that the position of the “Lost Soul” is essentially unchanged and in fact more highly resolved with the additional taxa. The sister taxa of the “Cacodemon”, the “Pain Elemental”, is highly similar in being a volant, cyclopian entity with head/body fusion, although has “Spiderdemon”-like arms, “Cyberdemon”-like horns and bizarrely spits out “Lost Souls”; horizontal gene transfer seems like a likely explanation for this hodgepodge.

There are reports of a third incursion on a Mars base, however the high resolution footage is unfortunately far too dark to be of any use. There are projections that in a few years a fourth incursion will occur, so I advise future researchers to grab their double-barreled shotguns, strap a flashlight to the top, and bag some type specimens.

I’m not making these numbers up: here’s the data sheet. I can’t upload .nex files for some reason, but they can be easily recreated using that data. I should clarify that this isn’t phylogenetics — the study of evolutionary relationships — however, it is still cladistics — grouping based on shared, derived characteristics. I suppose ideas can evolve as designers swap and redesign ideas, and it does seem that cladistics can group them reasonably well. Of course, there could very well be some severe methodological flaws that I overlooked or a better method (phenetics?) but, eh, it’s April 1st.

This post owes a lot to the Doom Wiki, Spriters Resource, and of course the folks at id Software who made the games.

The Hidden Necks of Seals

Harbor Seal at Roger Williams Park Zoo

I’d bet that most casual observers of Harbor Seals (Phoca vitulina) are under the impression that the little pinnipeds are almost neckless. Of course, it’s not immediately obvious what the skeletal proportions are underneath that blubber, but judging by the forelimb origin, it would seem the neck is less than half the length of the head. Harbor Seals are hiding more neck than what they let on, as their cervical vertebrae are actually similar in length to the skull:

Harbor Seal skeleton from Museum of Comparative Zoology

Clearly the live animal above was not holding its neck in the same posture as this skeleton, and (not having X-Ray specs) I’d assume it was similar to the deep “S” curve in this Harp Seal. As for why seals would shorten their apparent necks so dramatically, King (1983) suggested phocids (“true” seals) require a spindle-like shape when swimming since their propulsion comes from oscillating the posterior end of their body. But why bother having a neck at all? A strongly retracted neck gives seals “slingshot potential” to capture prey (Rommel & Reynolds 2002), as alarmingly demonstrated by this Leopard Seal. It’s surprisingly difficult to find photographs of Harbor Seals showing off their full neck — presumably they only do it rarely and briefly — but blogger Kitty Kono has an amazing snapshot:

From Kitty Kono’s blog Back in the U.S.A. Used with permission.

I of course covered all this in my Weddell’s Long-Necked Seal article, but now, I’ll take things further by determining just how long seal necks are. The tails and sacral vertebrae varied much more than what I expected (plus one source often lumped the two), so rather than measure necks relative to the length of the entire spine, I did so relative to only the thoracic and lumbar vertebrae (T–L from here on). And yes, there is going to be an appendix to this blog post.

Black = Skull (gray for no data); Red = Cervical, light blue background equal to shortest neck, pink equal to longest neck; Blue = Thoracic; Green = Lumbar; Yellow = Sacral; Orange = Caudal.
Species are (top to bottom): Dog, Bearded Seal (Erignathus), Weddell Seal (Leptonychotes), Southern Elephant Seal (Mirounga leonina), Leopard Seal (Hydrurga), Hooded Seal (Cystophora), Harbor Seal (Phoca vitulina), Ringed Seal (Pusa hispida), Harp Seal (Pagophilus).

Phocid necks range from 21% T–L in Bearded Seals to 35% T–L in Harp Seals*, which falls short of dogs with necks 40.5% of their T–L. Weddell seals were initially described as “long-necked”, so it’s amazing to see they’re at the low end of the spectrum with necks only 23% T–L. Contemporary sources almost always describe Leopard Seals as “long necked”, however their necks are only 29% T–L, so perhaps “thin-necked” would be a more apt description. The extinct seal Acrophoca is also typically described as “long-necked”, although judging from this skeletal illustration and mounted specimen, the neck is around 30% T–L. The closest true seals have to long necks come from members of the “tribe” Phocini (Phoca, Pusa, Pagophilus), although I have no idea why that would be the case.

* Piérard (1971) cites a source giving 35% for Harbor Seal T–L, so my figure above is probably a shorter-necked young individual.

Northern Fur Seals (Callorhinus ursinus) at Mystic Aquarium.

As for otariids (“eared seals”) — sometimes described as having “snakelike” necks (e.g. Riedman 1990) — do they truly have long necks, or is this a deception from thin necks held out straight? Otariids require a considerable amount of mass before and after their foreflippers (their source of propulsion) for stability, and so they keep their necks out fairly straight (King 1983). Phocid and otariid necks have been described as “similar” in length (Rommel & Reynolds 2002), although just to be on the safe side, I’ll quantify this as well:

Otariid necks vary little, from 34.5% T–L in Australian Sealions (and most other being only slightly higher) to 41% T–L in Northern Fur Seals. So there is certainly quite a pronounced difference in neck length between Bearded Seals and Northern Fur Seals, it does not seem that the average phocid, otariid or walrus is not truly that different in neck length. It should be cautioned that proportional neck length can change considerably during maturity, so there is certainly some error in these figures. The Bearded Seal was reportedly an old female (Hayden 1880) so if anything, it may have had a longer neck than average.

One thing I haven’t mentioned so far is that pinnipeds have far longer tails than most observers would expect, ranging from 13.5% T–L in Northern Fur Seals to 41% T–L in Ringed Seals. I really have no idea why this would be the case.

References:

Allen, J. (1880) History of North American Pinnipeds. Available.

King, J. (1983) Seals of the World.

Piérard, J. (1971) Osteology and Myology of the Weddell Seal Leptonychotes weddelli (Lesson, 1826). Available. IN: Burt, W. (editor) Antarctic Pinnipedia.

Riedman, M. (1990) The Pinnipeds: Seals, Sea Lions, and Walruses.

Rommel, S. & Reynolds, J. (2002) Skeletal Anatomy IN: Perrin, W. et al. (eds.) Encyclopedia of Marine Mammals. Relevant Passage.

Skull Cerv. Thor. Lumb. Sac. Caud.
Dog (King) ? 17.00% 24.00% 18.00% 4.00% 37.00%
Bearded (Hayden) 230 250 800 390 175 350
Weddell (Piérard) 0 274 820 385 150 385
S. Elephant (Hayden) 480 570 1690 670 250 680
Leopard (King) ? 17.00% 37.00% 22.00% 3.00% 21.00%
Hooded (Hayden) 265 275 630 320 190 290
Harbor (Hayden) 220 210 445 216 120 230
Ringed (Hayden) 163 200 410 190 100 245
Harp (King) ? 19.00% 37.00% 17.00% 7.00% 21.00%
Walrus 390 400 1170 380 ? 550
N. Fur (Hayden) 275 430 770 270 160 140
N. Fur (Hayden) 245 360 680 245 145 145
N. Fur (Hayden) 200 200 520 185 105 160
N. Fur (Hayden) 185 172 470 173 95 120
Aus. Sealion (King) ? 20.00% 43.00% 15.00% 7.00% 15.00%
Aus. Fur (King) ? 21.00% 44.00% 15.00% 6.00% 13.00%
Cal. Sealion (Hayden) 236 320 640 230 ? 280
Steller’s (Hayden) 374 500 1050 340 ? 440
Steller’s (Hayden) 385 540 1090 400 ? 520

Data from King (1983) were in percentage of the entire spine with no data on skull length. Some Data from Hayden (1880) is in millimeters, and for instances where sacral and caudal vertebrae were lumped, I signified this with “?” in the area for sacral measurement.

Weddell’s Long-Necked Seal

From Weddell (1825).

Experts are not immune from making mistakes, even really bizarre ones. Ahem. Take James Weddell for instance, a keen observer of pinnipeds and other marine life (Fogg 1992) who somehow produced the monstrosity above. The intended subject isn’t any old seal, it’s a Weddell Seal (Leptonychotes weddellii)… mostly. The circumstances behind this illustration are vague and contradictory but Fogg (1992) reasoned it was based both on a specimen deposited in the Edinburgh Museum* and Weddell’s memory of wild seals, which may have conflated Weddell and Leopard Seals. It’s probably notable that Weddell referred to his namesake as a “Sea Leopard”.

* Now the National Museum of Scotland.

Weddell (1825) included a brief description of his preserved specimen from one Professor Jamieson who noted the “long and tapering” neck and small head, and argued that Weddell’s Seal had dentition distinct from a Leopard Seal’s. The following year René Primevère Lesson named the species “Otaria weddelli” from Jamieson’s description and Weddell’s illustration but not an actual examination of the specimen, which apparently means Weddell Seals don’t have a proper type specimen (Scheffer 1958). Nobody seems to know why Lesson classified Weddell’s Seal as a Sealion (hence “Otaria“) although I’d suspect it was due to the slender neck. So… what’s up with that mysterious neck?

From Hamilton (1839).

Hamilton (1839) described Weddell’s specimen as having a “proportionally very small” head and a “small, long, and tapering” neck, however the accompanying illustration makes it clear these traits are quite subtle, at least compared to Weddell’s illustration. Hamilton (1839) also took measurements — unfortunately “over the back” — but it’s still interesting that the distance from the snout to the base of the fore-flipper is 1.04 meters compared with a snout-tail length of slightly under 3 meters. It would seem remarkable for a “true” seal to have a head and neck length around one third that of the body, but in fact, it’s totally normal.

Weddell Seal in a more typical pose. From Richardson & Gray (1845).

Despite external appearances, seals and sealions have necks that are proportionally similar in length, although seals typically hold theirs in a deep “S” curve (Rommel & Reynolds 2002). I would highly recommend clicking on this link — the disparity between the external “neck” and the length of cervical vertebrae is truly astounding. As for why seals do this, it’s for “slingshot potential” to capture prey (Rommel & Reynolds 2002), so they’re apparently like snapping turtles, except they hide their necks in blubber rather than a shell. Anyways, Weddell Seals have cervical vertebrae that take up 14% of the vertebrae column (including the tail), and the series is slightly longer than the condylobasal length of the skull (Piérard 1971), so the proportions described by Hamilton are indeed plausible. The posture still seems odd — I can’t find any photographs of a Weddell Seal in such a pose — and I wonder if whoever mounted Weddell’s specimen did so Leopard Seal-style, since that species appears to hold its neck out fairly straight for a “true” seal. It would be interesting to see what the mount actually looks like, but unfortunately, I haven’t been able to track down any photographs.

Since I couldn’t provide a photograph of a Weddell Seal in a weird pose, this walrus will have to do:

From Scheffer (1958).

I can’t help but think of Parson’s long-necked seal and if that was another example of a specimen mounted with an extreme posture whose morphology was exaggerated even more by an illustrator. Curiously, some early workers considered Parson’s and Weddell’s seals to be synonymous (Hamilton 1839), but whatever Parson’s seal was, it probably wasn’t an Antarctic visitor.

References:

Allen, J. (1905) The Mammalia of Southern Patagonia. Reports of the Princeton University Expeditions to Patagonia 3(1) 1–210. Relevant Passage.

Fogg, R. (1992) A History of Antarctic Science. Relevant Passage.

Hamilton, R. (1839) The Natural History of the Amphibious Carnivora. Available. Relevant Passage.

Piérard, J. (1971) Osteology and Myology of the Weddell Seal Leptonychotes weddelli (Lesson, 1826). Available. IN: Burt, W. (editor) Antarctic Pinnipedia.

Richardson, J. & Gray, J. (1845) Zoology of the Voyage of the H.M.S. Erebus and Terror. Available. Relevant Passage. Illustration.

Rommel, S. & Reynolds, J. (2002) Skeletal Anatomy IN: Perrin, W. et al. (eds.) Encyclopedia of Marine Mammals.

Scheffer, V. (1958) Seals, sea lions, and walruses: a review of the Pinnipedia.

Weddell, J. (1825) A Voyage Towards the South Pole. Second Edition Available. Relevant Passage.

The Otter Civet

From the Museum of Comparative Zoology (Harvard)

Otter Civets (Cynogale bennettii) are a poorly known and endangered species of hemigaline viverrid from the Thai-Malay Peninsula, Borneo and Sumatra (Veron et al. 2006). There are also unconfirmed reports from northern Vietnam (“C. lowei“), southern China, northern Thailand and Java (Veron et al. 2006). The mount above appears to be this specimen, and was probably collected in Borneo in 1881 by Henry A. Ward. It certainly shows its age, but it’s no taxidermic aberration — photographs of live specimens show the whiskers and mystacial pads really are that ridiculously hypertrophied.

The illustration above demonstrates more remarkable morphology — the nostrils open dorsally, an even more extreme position than those of seals* and otters (Pocock 1915). Pocock (1915) speculated this feature allows Otter Civets to be ambush predators, picking off unsuspecting birds and small mammals looking for a drink. Nowak (2005) lists birds and small mammals as part of the Otter Civet’s diet and treats Pocock’s speculative behavior as likely, although it still appears to be entirely hypothetical. Any nature documentarians up for filming this potential mammalian mini-crocodile in action? Anyways, Otter Civets also have adaptations for activities below the surface as their nostrils can be closed with flaps, and their ears can be closed as well (Nowak 2005). While some early workers considered Otter Civets to have large orbits (Gregory & Hellman 1939), the eyes appear to be on the small side for a civet, which is unsurprising considering the vast array of whiskers.

* But not Leopard Seals, it would seem.

Viverrids... and prionodontid... on parade!

Top Row: Banded Linsang, Masked Palm Civet
Bottom Row: Binturong, Common Palm Civet, and Otter Civet.

Otter Civet weirdness doesn’t stop at the head. Despite their closest relatives being plantigrade, Otter Civets are fully digitigrade (Gaubert et al. 2005), which is rather unexpected for a semi-aquatic species. The feet are broad with flexible digits and some webbing (Nowak 2005). The tail is curiously short (compare to the civets… and prionodontid… above) and lacks specialized musculature (Nowak 2005). Due to the lack of webbing and underwhelming tail, Nowak (2005) speculated that Otter Civets are slow and unmaneuverable swimmers specialized for capturing cornered prey, which ties in with Pocock’s speculation that the abundant whiskers are an adaptation for discovering hiding prey. Aside from terrestrial species, their diet includes fish, crustaceans and possibly molluscs (Nowak 2005).

Top Row: Otter Civet, Aquatic Genet
Bottom Row: Hemigalus, Chrotogale
All skulls from Gregory & Hellman (1939).

Otter Civets are members of the clade Hemigalinae, along with Hemigalus, Chrotogale, Diplogale and, it was recently argued, Macrogalidia (Wilting & Fickel 2012). The skeletal comparisons above and below also include the Aquatic Genet (Genetta piscivora), a more distant relative that, as the name suggests, is also semi-aquatic. Gregory and Hellman (1939) discussed some minor skeletal traits shared by Otter Civets and Aquatic Genets but found the convergence to be minor. Otter Civet teeth really stand out: the elongate, serrated premolars are specialized for grasping prey while the blunt-cusped, rounded molars are specialized for crushing (Gregory & Hellman 1939; Nowak 2005). Gregory and Hellman (1939) also described an enlarged infra-orbital foramen and enlarged areas for muscle attachment anterior to the orbits which is related to the abundant whiskers and hypertrophied facial musculature, although it’s far less pronounced than what I would have expected. Curiously, there doesn’t seem to be any obvious anatomy relating to the strange position of the nostrils.

Top to bottom: Otter Civet, Aquatic Genet, Hemigalus
Skulls from Gregory and Hellman (1939).

Otter Civets have been kept in captivity and have apparently been observed foraging in water (Vernon et al. 2006), although, full disclosure, I cannot find any specific information on its behavior in water. On land it has been observed doing some surprising things — climbing trees, as well as eating fruit and insects (Nowak 2005; Wilting et al. 2010) — although most observations appear to be fleeting glimpses. Otter Civets are typically photographed nears ponds and streams and are thought to primarily inhabit peat-swamp and primary forests, although they have also been observed in logged and secondary forest (Wilting et al. 2010, Cheyne et al. 2010). However, observations of Otter Civets are becoming increasingly uncommon and it is believed habitat destruction has reduced its population (Veron et al. 2006).

And on a somewhat more upbeat note, here is some of the first footage of Otter Civets in the wild:

References:

Cheyne, S. et al. (2010) First Otter Civet Cynogale bennettii photographed in Sabangau Peat-swamp Forest, Indonesian Borneo. Small Carnivore Conservation 42 25–26. Available

Gaubert, P., et al. (2005) Mosaics of Convergences and Noise in Morphological Phylogenies: What’s in a Viverrid-Like Carnivoran? Systematic Biology 54(6) 865–894. Available

Gregory, W. & Hellman, M. (1939) On the evolution and classification of the civets (Viverridae) and allied fossil and recent Carnivora: A phylogenetic study of the skull and dentition. Proceedings of the American Philosophical Society 81 309–392. Available

Nowak, R. (2005) Walker’s Carnivores of the World.

Pocock, R. (1915) On some of the external characters of Cynogale bennettii Gray. Proceedings of the Zoological Society of London 15(88) 350–360. DOI:10.1080/00222931508693650

Veron, G. et al. (2006) A reassessment of the distribution and taxonomy of the Endangered otter civet Cynogale bennettii (Carnivora: Viverridae) of South-east Asia. Oryx 40(1) 42–49. DOI: http://dx.doi.org/10.1017/S0030605306000068

Wilting, A. & Fickel, J. (2012) Phylogenetic relationship of two threatened endemic viverrids from the Sunda Islands, Hose’s civet and Sulawesi civet. Journal of Zoology 288(3), 184—190. DOI: 10.1111/j.1469-7998.2012.00939.x

Wilting, A. et al. (2010) Diversity of Bornean viverrids and other small carnivores in Deramakot Forest Reserve, Sabah. Malaysia.Small Carnivore Conservation 42 10–13. Available

The Arachnid-Tailed Snake

From Fathinia et al. (2009)

In 1968, the Second Street Expedition across Iran collected what appeared to be a Persian Horned Viper with a Wind Scorpion attached to its tail. Examination of the specimen in 1970 revealed the apparent arachnid was actually a growth, but it could not be determined if it was some sort of reaction to a parasite, a tumor, or caused by genetics. A second specimen bearing a pseudo-arachnid was captured in 2001, and it became apparent that an entire species possessed this trait — Pseudocerastes urarachnoides (Bostanchi et al. 2006) Two live specimens were collected in 2008 and the tails were filmed in action:

An unnervingly convincing Wind Scorpion probably doesn’t seem very appealing to most humans — if urban legends about “Camel Spiders” are anything to go by — but Bostanchi et al. (2006) hypothesized the heavily modified tails are used as lures. To test this hypothesis, Fathinia et al. (2009) introduced a chick to an enclosure containing a snake; after half an hour the bird pecked the knob-like portion of the tail, was drawn in towards the head, and was struck and killed. The only animals P. urarachnoides has been known to prey on so far are birds, although it hasn’t been ruled out that other potential Wind Scorpion predators such as small mammals and reptiles are also sometimes taken (Fathinia et al. 2009). Aside from the confirmation of a caudal lure, examination of live specimens also revealed the scales are far more prominent than those of any other Iranian snake, possibly due to either the body being inflated or dermal muscles (Fathinia et al. 2009).

The awesomely rugged head of Pseudocerastes urarachnoides, from Fathinia & Rastegar-Pouyani (2010).

There is undoubtedly much about the biology of the Arachnid-Tailed Snake* that remains to be learned. The extent of its range is not certain, although it was recently discovered to overlap with two other Pseudocerastes species (Fathinia & Rastegar-Pouyani 2010). These “Gypsum Snakes”, as they’re known to some locals, are found in hills primarily made of gypsum and are hypothesized to ambush prey from bushes located near their burrows; however, there are anecdotes about them also ambushing prey from trees (Fathinia et al. 2009). I, for one, would be quite curious about any other “ethno-known” traits of this snake and how they stack up with reality.

* I’ve seen the name “Spider-Tailed Horn Viper” used, but the lure isn’t unambiguously spider-like. One local name is “Feathered Snake”, which is curious considering its diet.

Pseudocerastes urarachnoides by Omid Mozaffari. Public Domain image.

References:

Bostanchi, H. et al. (2006) A New Species of Pseudocerastes with Elaborate Tail Ornamentation from Western Iran (Squamata: Viperidae). Proceedings of the California Academy of Sciences 57(14) 443—450. Available

Fathinia, B. et al. (2009) Notes on the Natural History of Pseudocerastes urarachnoides (Squamata: Viperidae). Russian Journal of Herpetology 16(2) 134—138. Available

Fathinia, B. & Rastegar-Pouyani, N. (2010) On the species of Pseudocerastes (Ophidia: Viperidae) in Iran. Russian Journal of Herpetology 17(4) 275—279. Available

Cutting off the Trunk to Spite the Whale

A new look for Makaracetus bidens

In Trunks, Proboscides & Makaracetus, I argued the extinct whale Makaracetus bidens probably didn’t have a “trunk” or “proboscis”, contra Gingerich et al. (2005). For one thing, an overhaul of terminology resulted in ‘trunk’ no longer referring to a nasal appendage, ‘proboscis’ being restricted to tubular nasal/lip structures capable of grasping food, and all other elongate nasal structures being termed ‘prorhiscis’ (Milewski & Dierenfeld 2013). Makaracetus certainly had over-developed facial features compared to its cetaceous relatives, but it didn’t appear any more likely to have a “trunk” than, say, a camel.

Boar skull, courtesy of Markus Bühler.

One feature of Makaracetus I didn’t discuss in the last round were its maxillary fossae, which Gingerich et al. noted were also present in pigs. This feature is plainly visible on the boar skull above — it’s the virtual trench running from the orbits down the snout. These fossae provide attachment for the maxillolabialis superior and inferior, which are responsible for moving the protruding snout (Gregory 1920).

PiggyNoses

Pig snout musculature. From Gregory (1920)

What’s interesting is that pigs almost fit the definition of having a proboscis. Pigs can apparently grasp food items with both their nose and lip musculature, but fall short of the definition since only the disc is mobile (Milewski & Dierenfeld 2013). Does this mean Makaracetus may have had some sort of proboscis after all? Probably not. It’s notable that one trait shared by proboscides owners is directional olfaction (Milewski & Dierenfeld 2013), which seems like an unlikely trait for a cetacean to evolve, considering they lack the ability to smell underwater. Furthermore, pigs don’t have exclusive rights to maxillary fossae.

Top: Makaracetus from Gingerich et al. (2005)
Middle: Potamochoerus sp. from Gregory (1920)
Bottom: Macropus sp. from Gregory (1920)

Kangaroo maxillary fossae bear a surprising resemblance to those of Makaracetus — they’re similar in extent, only present anterior of the antorbital foramen, and are on the lower half of the rostrum. Unlike pigs, the maxillary fossae of kangaroos provide an origin for part of the buccinator muscle (Gregory 1920). The fossae are also present in baboons, where I suspect they have something to do with this display. Maxillary fossae also appear to be present in llamas but apparently not camels, for some reason. Considering the apparently variable functions of maxillary fossae and the additional premaxillary fossae of even more mysterious purpose, I’d agree with Gingerich et al.’s interpretation of “hypertrophied facial muscles” for Makaracetus and hesitate to speculate much further.

So if the nose of Makaracetus didn’t bear a proboscis or prorhiscis, what did it do? Perhaps the expanded nasal vestibule was merely a side effect of the snout warping into a down-turned shape. Another parallel could be found in Gray Seals, which have nasals retracted to a similar degree as Makaracetus and enlarged noses which function as displays (Miller & Boness 1979); however more specimens will be required to conclude that the trait was sexually dimorphic. Milewski & Dierenfeld (2013) hypothesized that the enlarged nose of Moose may act as a buoy to counterbalance to forelimbs when foraging underwater, a trait which could be beneficial to the apparently benthic-feeding Makaracetus. However, Makaracetus appears to have a much smaller nasal chamber than Moose, so the potential benefits could have been minimal.

I reconstructed Makaracetus as a Hippo/Manatee/Walrus-thing up top, but I suspect my endeavors were far too conservative. Makaracetus was a beast without obvious parallels and its true appearance can probably never be known. Still, there’s no reason to go slapping a “trunk” on strange-looking skulls, and I hope Milewski & Dierenfeld (2013) will get the attention it deserves and open minds to the myriad other possibilities of big, weird noses.

References:

Gingerich, P. et al. (2005) Makaracetus bidens, a New Protocetid Archaeocete (Mammalia, Cetacea) from the Early Middle Eocene of Balochistan (Pakistan). Contributions from the Museum of Paleontology 31(9) 197—210. Available

Gregory, W. (1920) Studies in comparative myology and osteology, No. V. — On the anatomy of the pre-orbital fossæ of Equidæ and other ungulates. Bulletin of the American Museum of Natural History 42 265—283. Available

Milewski, A. & Dierenfeld, E. (2013) A structural and functional comparison of the proboscis between tapirs and other extant and extinct vertebrates. Integrative Zoology doi: 10.1111/j.1749-4877.2012.00315.x

Miller, E. & Boness, D. (1979) Remarks on display functions of the snout of the grey seal, Halichoerus grypus (Fab.), with comparative notes. Canadian Journal of Zoology 57 140—148. Available