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View Full Version : How would my "Merhorse" be classified?



Tom Mazanec
2015-Sep-19, 05:12 PM
This is a question of cladistics using a story I wrote as an illustration only, not a cryptozoological question, so don't freak out.
In my story, the merhorse/sea serpent was depicted as a whale-sized, elongated descendant of a semi-aquatic mink-like miacis species that became completely aquatic (like Lutra), then oceanic (like Enydra) and finally turned into Cecil; while another species of miacis evolved into the carnivora order.
If we actually found such a species, how would we classify it? As a carnivora? As a separate order?

DonM435
2015-Sep-19, 05:18 PM
I think I'd settle upon one plausible known species, and attribute the other traits to convergent evolution.

Tom Mazanec
2015-Sep-19, 06:11 PM
I think I'd settle upon one plausible known species, and attribute the other traits to convergent evolution.

I'm not sure if I understand your answer. Yes, the "merhorse" is a convergent evolution with the pinnipeds, but would you join them with, say elephant seals, when they are not at all elephant seals (three or four times longer, different placement of flippers, etc not to mention having less DNA similarity than that between a mongoose and a walrus)?

DonM435
2015-Sep-19, 07:10 PM
Whatever you're comfortable with to start. Environmental pressures over the eons do the rest.

Tom Mazanec
2015-Sep-19, 08:00 PM
I am asking whether they would be put in a carnivora family or suborder or infraorder or a separate mammalian order.

DonM435
2015-Sep-19, 10:47 PM
I suspect that opinions would vary as to whether to separate them.

Colin Robinson
2015-Sep-19, 11:43 PM
This is a question of cladistics using a story I wrote as an illustration only, not a cryptozoological question, so don't freak out.
In my story, the merhorse/sea serpent was depicted as a whale-sized, elongated descendant of a semi-aquatic mink-like miacis species that became completely aquatic (like Lutra), then oceanic (like Enydra) and finally turned into Cecil; while another species of miacis evolved into the carnivora order.
If we actually found such a species, how would we classify it? As a carnivora? As a separate order?


I'm not sure if I understand your answer. Yes, the "merhorse" is a convergent evolution with the pinnipeds, but would you join them with, say elephant seals, when they are not at all elephant seals (three or four times longer, different placement of flippers, etc not to mention having less DNA similarity than that between a mongoose and a walrus)?

Taxonomists today try to classify organisms in monophyletic terms, that is, according to how much common ancestry there is. (Which often goes against traditional classifications.)

If the merhorse and the mongoose have a more recent common ancestor than the merhorse and the elephant seal, then the merhorse would be classified with the mongoose rather than with the elephant seal. Wouldn't matter how different from the mongoose it might be in size, shape and habitat, or how seal-like it might look due to convergent evolution.

If your newly discovered merhorse lineage were known to have a common ancestor with previously known carnivora which is more recent than any common ancestor it has with non-carnivorans, then the merhorses and their otter-like ancestors could be classified as a family within the order carnivora. Otherwise they would be classified as a separate order.

BigDon
2015-Sep-22, 10:50 PM
Wait, both elephant seals and mongeese are carnivorans. I missed something in the above exchange.

Colin Robinson
2015-Sep-22, 11:13 PM
Wait, both elephant seals and mongeese are carnivorans.

True. If the merhorse and the mongoose have a more recent common ancestor than the mongoose and the elephant seal, then the merhorse would be classed as a carnivoran like the elephant seal and the mongoose; but it would presumably go in suborder feliformia (like the mongoose) rather than caniformia (like the seals).