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Earth: Crocodile Empire homeworld (crocodiles part I)

The views expressed are those of the author and are not necessarily those of Scientific American.


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Highly simplified cladogram showing one of the several phylogenetic hypotheses proposed for crocodiles (this topology based on Brochu 2000a, b and McAliley et al. 2006). Photos (top to bottom) by Mo Hassan, Davric, Naish, Thesupermat (see below for licensing on last image).

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Prior to the epic destruction wrought upon their kind by the noble and beautiful Homo sapiens, crocodiles had it pretty good.

One thing that I’ve read several times and found especially annoying is the idea that crocodiles, alligators and gharials are “the last remnants of a once mighty empire”, or something along those lines. No, crocodiles and other living crocodilians are not anachronisms, relics or sorry vestiges of a former glory. It’s certainly true that living crocodilians do have a superficial similarity to the sorts of crocodilians known from fossils to have been around for more than 100 million years. But modern crocodilians don’t, contra all claims to the contrary, have especially long evolutionary histories and they’re no more anachronistic or archaic than numerous other living things that we take for granted and never consider ‘of the past’.

Close to the smile of a Salwater, Estuarine or Indopacific croc (C. porosus). Verily, a thing of such great beauty.

In fact, crocodiles alone (that is, totally ignoring alligators, caimans and gharials) include about 13 species that, historically, occurred across much of Africa, the American tropics, southern Asia and the Indopacific region. This diversity and this global range parallels or exceeds that of many living animals often regarded as the epitome of modernity and success, so “last remnants of a once mighty empire” my arse.

While those of us who care about such things will always remain frustrated by continuing descriptions of crocodiles and kin as “living dinosaurs”, or as “living fossils”, it is at least becoming better appreciated that crocodilians are actually complex creatures with interesting social lives, uncanny sensory abilities and a surprising, weird and sophisticated anatomy.

The crocodile consensus

On to a bit of phylogeny. One thing that’s been universally agreed upon for a while is that dwarf crocodiles (Osteolaemus) form the sister-group to Crocodylus [though, read on]. And I talk of dwarf crocodiles in the plural sense since, as you might remember from the previous crocodile article, it’s increasingly agreed that Osteolaemus contains more than one species. Incidentally, please assume in this article and those that follow that I’m using the word crocodile in the specific (correct) sense.

Slender-snouted crocodile (Mecistops cataphractus), photographed in captivity by Thesupermat. I originally thought that this photo actually showed a False gharial (Tomistome schlegelii) but a clearer dorsal view of the same animal reveals the scute pattern of Mecistops; it is definitely not a Tomistoma (SEE BELOW). Image licensed under Creative Commons Attribution-Share Alike 3.0 Unported, 2.5 Generic, 2.0 Generic and 1.0 Generic license.

An interesting surprise is that one species often imagined to be part of Crocodylus – the highly distinct Slender-snouted crocodile, conventionally Crocodylus cataphractus – is no such thing (that is, it isn’t a species of Crocodylus), but is in fact probably closer to Osteolaemus. The data supporting this is from nuclear and mitochondrial genes, and it clearly shows the Slender-snouted crocodile to be as distant genetically from Crocodylus as is Osteolaemus (Schmitz et al. 2003, McAliley et al. 2006). This means that cataphractus can’t be included in Crocodylus anymore; at least, not if we want to keep Osteolaemus separate from Crocodylus, as we do. The sister-group to Crocodylus thus consists entirely of African taxa; an observation that might indicate an African origin for Crocodylus itself (Brochu 2000a) (though see later articles in this series).

Slender-snouted crocodile, from Wermuth (1953). Click to enlarge.

The idea that cataphractus might not be especially close to Crocodylus is not actually novel. John E. Gray gave this species its own genus – Mecistops – back in 1844. More recently, Aoki (1976, 1992) argued that Mecistops should be treated as a distinct genus, and as a close relative of gharials and false gharials. Indeed, the common name African gharial has sometimes been used for this species. That last idea hasn’t been supported by other work (both molecular and morphological); anyway, the name Mecistops is now back in business for the Slender-snouted crocodile.

As for the relationships within the Crocodylus species, it’s fair to say both that contrasting phylogenetic hypotheses have been published, and that certain species have been recovered in radically different positions. Despite this, it’s probably most useful to imagine Crocodylus to consist of three main lineages: an Indopacific one, a New World one, and the Nile crocodile C. niloticus (e.g., Brochu 2000a, b, McAliley et al. 2006), as shown in the simplified cladogram above. To reiterate, and as we’ll see, the monophyly and content of these lineages has been challenged by various recent discoveries.

The scute pattern present on the anterior part of the dorsal shield, and in the cervical shield, shows that the crocodile shown above is indeed a Slender-snouted crocodile (Mecistops cataphractus), not a False gharial (Tomistoma schlegelii). Photo by Thesupermat, licensed under Creative Commons Attribution-Share Alike 3.0 Unported, 2.5 Generic, 2.0 Generic and 1.0 Generic license. Diagrams of scute patterns from Ross & Mayer (1983).

In this and the following few articles, we’re going to go through all the world’s living 13 or so crocodile species. The article continues the theme initiated with May’s ‘Dissecting a crocodile’ article. Rather than discuss the same sort of information you’ve heard before, my aim is to highlight recent ideas about phylogeny, history and diversity – the sort of material that rarely makes it into the popular and semi-popular literature. We start with the Mugger and other species that appear to be close to (but not necessarily part of) the Indopacific assemblage.

The Mugger or Marsh crocodile: from Iran to Burma

Basking Muggers in captivity. Photo by Kmanoj, licensed under Creative Commons Attribution 3.0 Unported license.

The Mugger C. palustris, also called the Marsh or Swamp crocodile (very occasionally, the Iranian crocodile), is uniformly dark with a relatively short, broad snout (proportionally the broadest of any crocodile, actually, sometimes being only 1.3 times as long as it is wide at its base). You can sometimes understand why a naive person might misidentify a Mugger as an ‘alligator’. Adult Muggers generally reach 4 m in total length, with 4.5 m probably being a maximum. Lengths of up to 8 m (Wermuth & Fuchs 1978) are reported in older literature. As with other crocodile species, extraordinary lengths of this sort should be considered highly unlikely: they are either mistakes or the result of exaggeration. The Mugger is mostly associated with freshwater habitats but its presence in coastal marshes is on record too. [Adjacent image by Kmanoj.]

Though usually thought of as an Indian animal, the Mugger also occurs in Pakistan, Nepal, Bangladesh, Bhutan and Burma. Or, at least, it did occur in these countries, since it now seems extinct in Bangladesh, Bhutan and Burma. The last records from Burma come from the 1860s, the last Bhutanese ones were seen in the 1960s, and the Bangladesh population might have lingered on until the 1990s. Occasional, rumoured sightings and the undetermined origins of captive specimens in small collections suggest that a few crocodiles might persist in the wild in these countries; either way, it’s clear that the animal has been eradicated from part of its historical range.

Mugger photographed in India by Herbert Ponting in 1907: the photo was originally labelled 'An Indian alligator'. Image in public domain.

It seems little known that the Mugger’s distribution extends west into southern Afghanistan and Iran. A 2007 survey estimated a population of 200-300 Muggers in Iran while the number present in Afghanistan seems unknown. I’ve been unable to learn anything about the alleged presence of the species in Afghanistan and am keen to know more – my only source for the presence of crocodiles in that country comes from the minutes of a 2006 “Crocodile Specialist Group Steering Committee Meeting”.

Dorsal scute compliment of a typical Mugger, from Ross & Mayer (1983).

I think I can just about identify a Mugger from the proportions of its head, and overall colour and body shape. But the best way to know that you’re dealing with a Mugger is to look at its dorsal osteoderm compliment. Muggers sometimes have a rather low number of scutes in each transverse dorsal row (four), but they can also have six or eight. The most anterior transverse band in the dorsal shield is often very short (that is, consisting of just two or four scutes) and may even be absent altogether. A band of granular skin then separates the dorsal shield from the cervical one; the latter typically consists of six reasonably large scutes (Ross & Mayer 1983). I should use this an opportunity to note that dorsal scute compliment really is the most reliable way of distinguishing crocodile species – other features that you might rely on, including size, colour and the general appearance of the jaws and teeth, are often unreliable.

The Mugger population on Sri Lanka supposedly differs from the typical form just described in having especially broad throat scutes and six longitudinal rows of dorsal scutes (as opposed to four). Accordingly, there have been various suggestions that it warrants taxonomic distinction. The names C. p. brevirostris and C. p. kimbula have both been used for this population.

The Mugger is recovered as the sister-taxon to the Indopacific assemblage in some studies (Brochu 2000b, McAliley et al. 2006), though positions especially close to C. porosus, C. mindorensis and C. siamensis have all been proposed on occasion. In fact, molecular data sets often find C. palustris, C. porosus and C. siamensis to group together (Li et al. 2007, Gatesy & Amato 2008, Feng et al. 2010, Man et al. 2011), and the Mugger and Siamese crocodile C. siamensis form a clade in some of these studies (Li et al. 2007, Man et al. 2011).

More soon. For previous Tet Zoo ver 3 articles on crocodilians, see…

As you’ll know if you follow me on twitter or facebook, Tet Zoo ver 2 has now been deleted in entirety. So, goodbye lengthy articles on sebecosuchians, giant fossil caimans, mekosuchines and a ton of other stuff.

Refs – -

Aoki, R. 1976. On the generic status of Mecistops (Crocodylidae), and the origin of Tomistoma and Gavialis. Bulletin of the Atagawa Institute 6/7, 23-30.

- . 1992. Fossil crocodilians from the late tertiary strata in the Sinda Basin, eastern Zaire. African Study Monographs 17, 67-85.

Brochu, C. A. 2000a. Congruence between physiology, phylogenetics and the fossil record on crocodylian historical biogeography. In Grigg, G. C., Seebacher, F. & Franklin, C. E. (eds) Crocodilian Biology and Evolution. Surry Beatty & Sons (Chipping Norton, Aus.), pp. 9-28.

- . 2000b. Phylogenetic relationships and divergence timing of Crocodylus based on morphology and the fossil record. Copeia 2000, 657-673.

Feng, G., Wu, X. B., Yan, P., & Li, X. Q. 2010. Two complete mitochondrial genomes of Crocodylus and implications for crocodilians phylogeny. Amphibia-Reptilia 31, 299-309.

Gatesy, J., & Amato, G. 2008. The rapid accumulation of consistent molecular support for intergeneric crocodilian relationships Molecular Phylogenetics and Evolution, 48, 1232-1237

Li, Y., Wu, X., Ji, X., Yan, P. & Amato, G., 2007. The complete mitochondrial genome of salt-water crocodile (Crocodylus porosus) and phylogeny of crocodilians. Journal of Genetics & Genomics 34, 119-128.

Man, Z., Yishu, W., Peng, Y. & Wu, X. 2011. Crocodilian phylogeny inferred from twelve mitochondrial protein-coding genes, with new complete mitochondrial genomic sequences for Crocodylus acutus and Crocodylus novaeguineae. Molecular Phylogenetic and Evolution 60, 62-67.

McAliley, L. R., Willis, R. E., Ray, D. A., White, P. S., Brochu, C. A. & Densmore, L. D. 2006. Are crocodiles really monophyletic? – Evidence for subdivisions from sequence and morphological data. Molecular Phylogenetics and Evolution 39, 16-32.

Ross, F. D. & Mayer, G. C. 1983. On the dorsal armor of the Crocodilia. In Rhodin, A. G. J. & Miyata, K. (eds) Advances in Herpetology and Evolutionary Biology. Museum of Comparative Zoology (Cambridge, Mass.), pp. 306-331.

Schmitz, A., Mansfeld, P., Hekkala, E., Shine, T., Nickel, H., Amato, G. & Böhme, W. 2003. Molecular evidence for species level divergence in African Nile crocodiles Crocodylus niloticus (Laurenti, 1786). C. R. Palevol 2, 703-712.

Wermuth, H. 1953. Systematik der Rezenten Krokodile. Mitteilungen aus dem Zoologischen Museum im Berlin 29, 375-514.

- . & Fuchs, K. 1978. Bestmmen von krokodilen und ihrer Häute. New York, Gustav Fischer.

Darren Naish About the Author: Darren Naish is a science writer, technical editor and palaeozoologist (affiliated with the University of Southampton, UK). He mostly works on Cretaceous dinosaurs and pterosaurs but has an avid interest in all things tetrapod. His publications can be downloaded at darrennaish.wordpress.com. He has been blogging at Tetrapod Zoology since 2006. Check out the Tet Zoo podcast at tetzoo.com! Follow on Twitter @TetZoo.

The views expressed are those of the author and are not necessarily those of Scientific American.





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  1. 1. himi-cat 8:19 am 06/12/2012

    Is there any record of the contents of Tet Zoo v2? It would be a tragedy to lose it forever (not least because I was in the process of reading through the archives systematically).

    A little more on-topic, your description of the dorsal scute patterns on the Mugger crocodile suggest that there’s a lot of variability – if that’s the case, what rules/patterns are used to distinguish between crocodile species? Is it simply that the various species’ range of variation doesn’t overlap?

    himi

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  2. 2. vdinets 9:38 am 06/12/2012

    Well, crocs are “living fossils” in the sense that their present-day diversity is much lower than it was, say, 70 mya. And their lifestyle probably hasn’t changed much, while birds, mammals and squamates have diversified into all kinds of new niches.

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  3. 3. naishd 10:41 am 06/12/2012

    Thanks for comments.

    Response to himi on the fate of Tet Zoo ver 2: apart from whatever is (temporarily) cached online, there seems to be no record of any of it anywhere, not even behind the scenes at wordpress. However, while the comments are essentially lost forever, the articles themselves (and their accompanying illustrations) are not lost – I of course have everything saved in my own files. I’m not yet sure how to deal with this vast amount of material – I mostly want to post new stuff here at Sci Am, not flood it with old content. We will see.

    Darren

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  4. 4. naishd 10:50 am 06/12/2012

    On intraspecific scute variation (see himi’s comment # 1): yes, there is a reasonable amount of variation within species. In cases, this might be because those ‘species’ actually include extremely distinct taxa that deserve species-level distinction. However, the bottom line is that you need to take note of numerous details of scute compliment into consideration when trying to identify an individual. Muggers, for example, may be variable with respect to number of dorsal scutes in each transverse row and in the number of scutes present in the post-occipital row, but, as a whole, this animal is still distinctive in other details (e.g., presence of typically six, relatively large scutes in close contact in the cervical shield, a distinct break between the cervical and dorsal shields, and so on). In these general respects, species tend not to overlap. And we of course combine this knowledge of scute compliment with details of skull form, overall size, proportions, pigmentation and so on. As we’ll see in later articles, there are certain populations whose specific identities and affinities remain the areas of debate.

    Darren

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  5. 5. Heteromeles 10:59 am 06/12/2012

    Darren, you could start “TetZombie 2″ on WordPress or similar to republish the material from TetZoo 2. Or just call it TetZoo 2.1.

    A semantic question: which came first etymologically, the mugger crocodile, or the human mugger who grabs purses?

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  6. 6. naishd 11:11 am 06/12/2012

    Vlad (comment 2): I didn’t know that a certain level of diversity was anything to do with ‘living fossil’ status – to be honest, I don’t think it’s relevant.

    As for the idea that modern crocodilians are conservative in lifestyle compared to birds, mammals and so on.. this is complicated. It’s true that there are, say, fossil alligators from the Oligocene that really don’t look all that different from modern kinds, but the same is true of (for example) waterfowl and swifts. And what’s especially interesting is that – while modern crocodilians do look superficially similar to, say, Jurassic and Cretaceous goniopholidids – it seems that any such similarities are likely superficial: that is, the lineage leading to all living species went through a small-bodied phase, apparently containing taxa (e.g., Isisfordia, Susisuchus) not necessarily similar to the classic, large, ‘crocodile-like’ species of the Mesozoic.

    Darren

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  7. 7. dinosauricon 11:13 am 06/12/2012

    Well there was a fair bit of croc diversity in the Late Pleistocene, into the Holocene even actually. Land-based Mekosuchids in New Caledonia and a host of other islands in the region. And I think there was also a lineage of marine gavialids in the South Pacific in the Late Pleistocene, if i’m not wrong. I’ll to check it out though. Not to mention the terrestrial predatory Quinkana in Australia’s Pleistocene as well.

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  8. 8. naishd 11:16 am 06/12/2012

    On that “fair bit of croc diversity in the Late Pleistocene” (comment 7), Tet Zoo ver 2 famously included several articles on mekosuchines, Indopacific gharials, Aldabrachampsus from Aldabra and Voay from Madagascar. Hmm, something else to prioritise, perhaps.

    Darren

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  9. 9. dinosauricon 11:23 am 06/12/2012

    Darren, just wondering, how much is known about Quinkana anyway? I’ve been trying but I can’t find much on it.

    Did it play an important role as a predator in the Pleistocene ecosystem? How big did it get anyway? I’ve seen sites quoting anywhere between 3 to 7m.Intraguild predation with Megalania perhaps?

    Would be exciting to watch a death match like that.

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  10. 10. Heteromeles 12:02 pm 06/12/2012

    I’d point out that bird body design has been pretty freaking conservative since the Mesozoic. The reason is that flying imposes strong constraints on both body shape and size. Despite this, nobody calls birds living fossils.

    Similarly, crocodilian lifestyles impose a set of substantial constraints on morphology, so we shouldn’t be surprised that they all look similar and have for a long time. The same constraint issues apply to say, designing an attack submarine. No one calls subs obsolete warcraft, even though the ones now look similar to the ones in WWI or even in the American Civil War (unlike, say, tanks or aircraft carriers). No matter what’s inside, they’re going to all look similar, just because of what they have to do.

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  11. 11. BrianL 12:16 pm 06/12/2012

    Tet Zoo 2 completely deleted? That’s pretty dreadful news for us and anyone seriously interested in tetrapods in general!

    I can see not wanting to flood Tet Zoo 3 with old articles, so I second the proposal for a Tet Zombie site of some sort. Might you not allow someone you trust to post those articles there, so that you can focus on Tet Zoo 3 yourself?

    As for starting another series, now on crocodiles: Awesome as always, but to quote Sergeant Wilson in Dad’s Army: “Do you really think that’s wise, sir?” I could imagine you losing track of all the series you want to finish. That being said, the vesper bat series did get finished, despite being lengthy.

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  12. 12. naishd 12:24 pm 06/12/2012

    On starting another series (BrianL, comment 11): you’re right, it’s not wise. But my philosophy on blogging is (as in that Simpsons episode) “Do what you feel”. In other words, write (and publish) on whatever it is that grabs your enthusiasm. Having said that, I’ve learnt my lesson from past yet-to-be-completed article series, so these days I actually finish the WHOLE SERIES _BEFORE_ I start publishing. So… crocodiles of the world: all done. Petrels of the world: also, all done.

    While we’re here, which series didn’t get completed on Tet Zoo ver 2? (1) Temnospondyls, (2) Gekkotans, (3) Anurans, (4) Sacs and pouches in the heads, necks and chests of mammals… I’m sure there are others. Coincidentally, I just started a ‘Tet Zoo To-Do-List’ on twitter, #TZTDL.

    Darren

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  13. 13. Andreas Johansson 1:03 pm 06/12/2012

    Speaking of Pleistocene diversity, I suppose one could, on that count, call the last surviving Homo species a living fossil.

    But enormous diversity doesn’t stop many people from thinking anurans or squamates somehow archaic, so I suspect the real driver of the perception is a “progressivist” view of evolution where amphibians are succeeded by reptiles who are succeeded by mammals. Any “offshoots” from the trunk from primitive vertebrates to familiar mammals that fail to go extinct tend to be regarded as relicts (birds being the big exception.)

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  14. 14. BrianL 2:01 pm 06/12/2012

    If we assess ‘living fossil’-status by phylogenetic decline since the Pleistocene, is there any living clade that is not composed of living fossils? To hell with asking a genie in the lamp to grant you the wish of perpetual wealth, a cure to cancer or world peace: Ask him to bring back healthy populations of all species that went exist because of human impacts, except ones that cause diseases! Fascinating though the subject is, it tends to be bad for my mood to think of the sheer number of species lost since the late Pleistocene because of anthropogenic causes.

    Regarding crocodiles, is there any possibility that *Crocodylus* might someday reconquer the Mediterranean via the Suez Canal? I suppose it’s unlikely.

    As for *Mecistops*, Diergaarde Blijdorp in Rotterdam has two individuals who’ve been there since before World War 2. They actually survived the German bombardments on the city (and the zoo). They’ve laid eggs in the past, but have never bred despite being over 80 years old by now. I used to see them at least once a week and the two seemed to be still going strong. It’s been nearly a year since I last got to see them though.

    Beautiful creatures and very distinctive, as crocodiles go. While they’re not overly big (About 2.5 to 3 meters, I guess), especially the larger individual has a pretty impressive width, both absolutely and compared to the adjacent Nile Crocodiles. Is *Mecistops* truly broadbodied compared to other crocodiles or is this an illusion created by the narrow skull? Or would this just be individual variation or physiology at work? The one in the top picture seems to be nothing special in that regard, but the lower one does seem to have a broad body.

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  15. 15. vdinets 3:27 pm 06/12/2012

    Darren: there is no official definition of “living fossil” as far as I know. My impression was that the taxa usually called “living fossils” (i. e. Nautilus, Monoplacophora, Tuatara, Latimeria etc.) are just that: descendants of formerly more diverse groups, similar to their ancestors in overall appearance. They don’t have to look identical, just similar. And they don’t have to be barely alive: Nautilus, for example, has a few species and seems to be doing generally well in its extensive range. But birds, for example, are too diverse to qualify, and extant Monotremes are too modified. Of course, all these criteria are very arbitrary, and there is no consistency in use: I’ve seen rhinos called living fossils simply because they look “ancient”.

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  16. 16. vdinets 3:53 pm 06/12/2012

    BrianL: AFAIK, there are no coastal croc populations in the Red Sea (there are some in Kenya, but that’s a bit far away). A more likely route for recolonizing the Mediterranean would be through the Nile (there are a few crocs above the Aswan Dam), but for that to happen, Egypt would have to become depopulated and the Dam would have to fail. And for that to happen, Israel would have to elect a really, really hawkish prime minister :-)

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  17. 17. John Harshman 4:31 pm 06/12/2012

    You make a slightly wrong statement near the beginning, when you claim that Osteolaemus is the sister group of Crocodylus, but then you fix it right after that. Since the idea that Mecistops is sister to the former is so new, I don’t know if it would widely be considered settled (though I believe it), so it isn’t clear what single topology in that neighborhood you could reasonably claim as the consensus, other than that Osteolaemus and Mecistops, whatever their mutual relationships, are the two closest relatives of Crocodylus.

    I hope you intend to deal with (I mean, have dealt with) the ages of taxa and the problems that causes for the inclusion of various fossils in various extant families. Once you get away from extant species, the phylogeny of Crocodylia/Crocodylomorpha/whatever becomes problematic.

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  18. 18. John Harshman 4:35 pm 06/12/2012

    Could we consider a relic as a taxon that had a much higher disparity in the past? There are, for example, currently no terrestrial crocs. There have been times in the past in which crocs occupied a much wider range of lifestyles than currently. Especially if you consider them as the inheritors of all the crododylian total group, which I hesitate to try to assign a name to. (Does it really have to be Pseudosuchia?)

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  19. 19. naishd 5:06 pm 06/12/2012

    Loving these comments – can’t respond to everything of course. On the sister-group relationship between Osteolaemus and Crocodylus (comment 17), what I meant to do there was explain the status quo prior to the new discoveries about Mecistops. Hopefully it’s clear now.

    As for fossil crocodilians… I’m aiming to work through them in time. But, then, I aim to do a lot of things.

    Darren

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  20. 20. Bret Newton 6:25 pm 06/12/2012

    In my view, the only animal you could call a “living fossil” is something like Catagonus. An animal known from the fossil record before it was know to be living by scientists.

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  21. 21. LeeB 1 6:58 pm 06/12/2012

    Tet Zoo v 2 is not even stored on the internet wayback machine because it disallowed robot crawlers from copying it.
    Really clever.
    And regarding fossil crocodiles, hopefully you plan to cover the recently named large fossil Crocodylus species from East Africa and their relationship to living African crocodylus species.

    LeeB.

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  22. 22. HowardRichards 7:37 pm 06/12/2012

    I believe Pooh-Bah had the correct response to such comments: “Oh, my protoplasmal ancestor!”

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  23. 23. Mythusmage 8:16 pm 06/12/2012

    Have any crocodilian remains been found in Iraq? Because the dragons of the Ishtar Gate had to come from somewhere.

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  24. 24. Christopher Taylor 10:12 pm 06/12/2012

    I’m not yet sure how to deal with this vast amount of material – I mostly want to post new stuff here at Sci Am, not flood it with old content.

    Darren, you could start “TetZombie 2″ on WordPress or similar to republish the material from TetZoo 2. Or just call it TetZoo 2.1.

    Ahem… darrennaish.blogspot.com is still sitting there…

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  25. 25. Heteromeles 10:52 pm 06/12/2012

    Personally, I tend to agree with one friend who said that the only “living fossils” are exactly that: living and fossilized. I think those putative living bacteria from amber-preserved bees might count, but certainly no metazoan that I’m aware of qualifies.

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  26. 26. vdinets 11:12 pm 06/12/2012

    Bret: interesting suggestion… but the prevailing use in popular literature is more or less what I described, and I don’t think it’s worth fighting with. As for scientific literature, I wouldn’t recommend using it at all :-)

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  27. 27. llewelly 11:46 pm 06/12/2012

    Zombie Gorgosaurus: The original living fossil.

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  28. 28. Dartian 1:59 am 06/13/2012

    Darren:
    Tet Zoo ver 2 has now been deleted in entirety

    The most appropriate response to that rhymes with ‘clucking bell’! Is the Shiny Digital Future here yet?

    On-topic: How ecologically similar – or dissimilar – is the mugger to the Nile crocodile*? A priori, one might naively assume these species to be each other’s opposite numbers in their respective continents, but their morphological differences (e.g., regarding snout shape) seems to suggest otherwise. Am I right to suspect that the Nile crocodile is, ecologically speaking, more of a generalist than the mugger is?

    * Sensu lato; I’m aware of recent suggestions to split the extant Nile crocodile into two different species – but I suppose you’ll be covering that ground in some future part of this article series.

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  29. 29. Heteromeles 10:15 am 06/13/2012

    Now that it’s a few days later, perhaps we can start The Legend of TetZoo 2, The Lost Library.

    Personally, I think that the best way to do this is (as with the Library of Alexandria project) to rebuild TetZoo 2 somewhere else, all the while wailing about how the comments on the new version just weren’t as good as the comments on the original. But then again, I’m not nearly as busy as Darren.

    Maybe someone can start a fan site, with bootleg essays?

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  30. 30. naishd 10:31 am 06/13/2012

    Re: comment 28 (how similar is the Mugger to the Nile crocodile, in ecological terms) – the Mugger seems to be a generalist, with everything from insects, molluscs and fish to frogs, birds, snakes and such mammals as dogs, leopards, deer, goats, and antelopes being recorded as prey items. Fish and insects might make up the bulk of its diet, and large animals are of course over-represented in popular accounts since the eating of such prey is more interesting. They do attack and kill people on occasion: Vyas (2010) reported 14 attacks, six of which were fatal, between 1987 and 2007.

    In general terms, it seems that Mugger and Nile crocs are similar overall in terms of ecology and diet. Nile crocodiles are of course covered in the series.. but I have to get through the members of the Indopacific assemblage (and its hangers-on) first.

    Darren

    Ref – -

    Vyas, R. 2010. Mugger (Crocodylus palustris) population in and around Vadodara City, Gujarat State, India. Russian Journal of Herpetology 17, 43-50.

    Link to this
  31. 31. vdinets 11:58 am 06/13/2012

    I wonder if mugger’s more massive head compared to Nile croc(s) has something to do with non-softshell turtles being historically more abundant in Asia than in Africa.

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  32. 32. Andreas Johansson 1:16 pm 06/13/2012

    A semantic question: which came first etymologically, the mugger crocodile, or the human mugger who grabs purses?

    According to the Online Etymological Dictionary, the later is etymologically someone who punches people in the face, from “mug” (as in “mug shot”), in turn, by some bizarre turn of slang, from “mug” = drinking vessel.

    Mugger the crocodile OTOH is from an Indic word for crocodile.

    Link to this
  33. 33. Heteromeles 2:31 pm 06/13/2012

    Another beautiful etymology, slain by cold reality. Oh well. Thanks Andreas!

    Link to this
  34. 34. Hai~Ren 12:25 am 06/14/2012

    The mugger crocodile is the species featured in The Undertakers, one of Rudyard Kipling’s stories in the Second Jungle Book:

    “It was a twenty-four-foot crocodile, cased in what looked like treble-riveted boiler-plate, studded and keeled and crested; the yellow points of his upper teeth just overhanging his beautifully fluted lower jaw. It was the blunt-nosed Mugger of Mugger-Ghaut, older than any man in the village, who had given his name to the village; the demon of the ford before the railway bridge, came—murderer, man-eater, and local fetish in one. He lay with his chin in the shallows, keeping his place by an almost invisible rippling of his tail, and well the Jackal knew that one stroke of that same tail in the water would carry the Mugger up the bank with the rush of a steam-engine.”

    Link to this
  35. 35. vdinets 2:06 am 06/14/2012

    Hai-Ren: I used the opening lines of that story as an epigraph to my dissertation on croc songs :-)

    Link to this
  36. 36. Dartian 3:22 am 06/14/2012

    Darren:
    the Mugger seems to be a generalist, with everything from insects, molluscs and fish to frogs, birds, snakes and such mammals as dogs, leopards, deer, goats, and antelopes being recorded as prey items

    I knew that (the source for leopard as a prey item is Dunbar Brander from the 1920ies, right?), but those are anecdotal data. Are there any modern, systematic comparative studies of the dietary habits of these crocodilian species?

    it seems that Mugger and Nile crocs are similar overall in terms of ecology and diet

    But ‘similar’, of course, does not necessarily equal ‘same’. (A jaguar is very similar to a leopard in many respects, but it’s different from it in others.) Let me re-phrase my original question:

    We know for a fact that there are morphological differences (notably regarding snout shape) between palustris and niloticus. Are these morphological differences related to differences in ecology or behaviour between these crocodile taxa?

    Diet is, of course, an obvious possible explanation here. Thus, it’s interesting that there are notable differences between the respective ‘large freshwater predator’ guilds in Africa and the Indian subcontinent. In the former, there is, for the most part, just the Nile crocodile (true, there are other extant crocodile species in Africa too, but they are much smaller than niloticus and – please correct me if I’m wrong – they typically do not occur in sympatry with it). In India, by contrast, the mugger at least locally occurs in sympatry with the fish-eating gharial (and also with the equally fish-eating river dolphins Platanista). To me, that seems like a textbook case of a situation where evolutionary character displacement – that is, specialisation – might occur. In order to avoid competition with gharials and river dolphins, there might therefore conceivably be selection against fish-eating in the mugger; are there dietary studies suggesting that this is, in fact, the case?

    Finally, if the mugger and the Nile crocodile do not significantly differ ecologically despite occupying different positions in morphospace, what are the implications of that observation for the reconstruction of the lifestyles of dinosaurs and other extinct archosaurs? If we observe cranial shape differences of similar magnitude between (say) Albertosaurus and Daspletosaurus, must we then conclude that those differences do not inform us anything about their possible differences in ecology?

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  37. 37. naishd 4:42 am 06/14/2012

    Dartian (comment 36): great questions, but I don’t really know the answers as I haven’t seen ANY detailed work on Mugger ecology/dietary preferences, partly because not that much seems to be published (I mean, as goes detailed study). If anyone knows of such work, please let us know. Actually, there is…

    Kumar, V., Choudhury, B. C. & Soni, V. C. 1995. Dietary habits of the mugger (Crocodylus palustris) in Andhra Pradesh, south India. Hamadryad 20, 8-12.

    Whitaker, R 1976. Status and ecology of the marsh crocodile in south India. Madras Snake Park Publication. Field Report 1976, 1-5.

    … but I haven’t seen them.

    The impression I get is that, as noted above, invertebrates and fish form the bulk of the diet as they do in many other Crocodylus crocodiles, but this doesn’t necessarily mean overlap with gharials or river dolphins since both presumably feed on smaller fish. Muggers and Gharials are truly sympatric, even occurring along the same river stretches in some regions.

    Darren

    Link to this
  38. 38. Dartian 5:22 am 06/14/2012

    Darren:
    this doesn’t necessarily mean overlap with gharials or river dolphins since both presumably feed on smaller fish

    Good point; there are, of course, different kinds of piscivory, too.

    I wonder if muggers tend to scavenge more often than other species of crocodiles? They certainly seem to come fairly often into conflict with tigers over this (at least if nature documentaries are anything to go by).

    Link to this
  39. 39. Brad McFeeters 3:17 pm 06/14/2012

    “It seems little known that the Mugger’s distribution extends east into southern Afghanistan and Iran.”

    Very little known, because those countries are west of India.

    Link to this
  40. 40. vdinets 3:24 pm 06/14/2012

    Dartian: Nile crocs (especially C. suchus) are sympatrical with fish-eating, narrow-snouted Mecistops over much of their range. There isn’t much habitat separation, and Mecistops isn’t much smaller than C. suchus. The size and habitat differences with Osteolaemus are more pronounced, although recently the latter have moved into areas where Nile crocs have been exterminated (i. e. mangroves of Cameroon). However, to my knowledge there is no difference in snout morphology between Nile crocs in Western/Central Africa (the area of sympatry) and Eastern/Southern Africa.
    Also, all crocs (even gharials) would scavenge given a chance, and I would be surprised if muggers are more enthusiastic about it than Nile crocs.

    Link to this
  41. 41. David Marjanović 5:44 pm 06/14/2012

    Response to himi on the fate of Tet Zoo ver 2: apart from whatever is (temporarily) cached online, there seems to be no record of any of it anywhere, not even behind the scenes at wordpress.

    What…

    …the fuck.

    Perhaps that’s some bizarre temporary byproduct of overhauling the site and restoring the comments. If not, raise a fucking stink.

    I didn’t know that a certain level of diversity was anything to do with ‘living fossil’ status –

    If it’s diverse now, it’s not a living fossil. That’s a criterion I’ve seen again and again and again.

    And I think there was also a lineage of marine gavialids in the South Pacific in the Late Pleistocene

    What, that late!?!?!

    the crododylian total group, which I hesitate to try to assign a name to. (Does it really have to be Pseudosuchia?)

    As I’ve said before, the PhyloCode is against Pseudosuchia (scroll down to the bottom of the page) and for an unrestricted emendation of Crurotarsi.

    the dragons of the Ishtar Gate had to come from somewhere

    You think so? Take a lizard, blow it up in your imagination, add a few body parts from other animals…

    the face, from “mug” (as in “mug shot”), in turn, by some bizarre turn of slang, from “mug” = drinking vessel

    It’s not particularly bizarre to liken the head to an empty vessel. See noggin… and German Kopf, which is from Latin cuppa, which is also where cup comes from. Further see French tête and Italian testa, from Latin testa “shell”.

    Link to this
  42. 42. David Marjanović 5:47 pm 06/14/2012

    an unrestricted emendation of Crurotarsi

    …er, what would be an unrestricted emendation if the PhyloCode were already in effect and Crurotarsi had already been established (with its current definition, which includes a phytosaur or maybe the group as a whole as an internal specifier).

    Don’t hold back. Just use Crurotarsi and specify once how you’re using it.

    Link to this
  43. 43. naishd 7:28 pm 06/14/2012

    Comment 39…

    “Very little known, because those countries are west of India.”

    Dammit, why did no-one point this out earlier? Thanks.

    Darren

    Link to this
  44. 44. BilBy 9:31 pm 06/14/2012

    @Hai-Ren – although it is not up there with Kipling, Harry Flashman meets some crocodiles when running away from Indian Mutiny trouble in ‘Flashman and the Great Game’ – he rather testily reports that he couldn’t identify the species. Also, Darren, I hope when you get on to C. niloticus you will be mentioning the book ‘Eyelids of Morning’?

    Link to this
  45. 45. Dartian 4:59 am 06/15/2012

    If we’re listing appearances of palustris in Western fiction, let’s not forget those, ahem, slightly American alligator-like mugger crocodiles seen briefly in Indiana Jones and the Temple of Doom;)

    Link to this
  46. 46. Mythusmage 9:20 pm 06/15/2012

    David,

    The dragons look a lot like what a crocodile would look like if you didn’t know what a crocodile looked like. Besides, the marshes of Mesopotamia looked like prime crocodile ground.

    In any case, you didn’t answer the question.

    Link to this
  47. 47. David Marjanović 5:38 pm 06/16/2012

    The dragons look a lot like what a crocodile would look like if you didn’t know what a crocodile looked like.

    Good. How about tales of crocodiles from Egypt? Contact with Egypt was established pretty early on.

    In any case, you didn’t answer the question.

    That’s because I can’t, not knowing the answer and all.

    However, if crocodiles had lived there in historical times, I’d probably know it. Maybe the ice ages drove them out, and then they couldn’t come back across the desert or the sea?

    Link to this

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