Taxonomy Steller's sea cow

1 taxonomy

1.1 phylogeny
1.2 research history
1.3 illustrations

taxonomy
phylogeny

steller s sea cow member of genus hydrodamalis, group of large sirenians, sister taxon dusisiren. of steller s sea cow, ancestors of dusisiren lived in tropical mangroves before adapting cold climates of north pacific. hydrodamalis , dusisiren classified in subfamily hydrodamalinae, diverged other sirenians around 4 8 mya. steller s sea cow member of family dugongidae, sole surviving member, , steller s sea cow s closest living relative, dugong (dugong dugon).

steller s sea cow direct descendant of cuesta sea cow (h. cuestae), extinct tropical sea cow lived off coast of western north america, particularly california. cuesta sea cow thought have gone extinct due onset of quaternary glaciation , subsequent cooling of oceans. many populations died out, lineage of steller s sea cow able adapt colder temperatures. takikawa sea cow (h. spissa) of japan thought of researchers taxonomic synonym of cuesta sea cow, based on comparison of endocasts, takikawa , steller s sea cows more derived cuesta sea cow. has led believe takikawa sea cow own species. evolution of hydrodamalis genus characterized increased size , loss of teeth , phalanges response onset of quaternary glaciation.

research history

steller s sea cow discovered in mid-18th century (1741) georg wilhelm steller, , named after him. steller researched wildlife of bering island while shipwrecked there year; animals on island included relict populations of sea cows, sea otters, steller sea lions, , northern fur seals. steller s account included in posthumous publication de bestiis marinis, or beasts of sea, published in 1751 russian academy of sciences in saint petersburg. zoologist eberhard von zimmermann formally described stellar s sea cow in 1780 manati gigas. biologist anders jahan retzius in 1794 put sea cow in new genus hydrodamalis, specific name of stelleri, in honor of steller. in 1811, naturalist johann karl wilhelm illiger reclassified steller s sea cow genus rytina, many writers @ time adopted. name hydrodamalis gigas, correct combinatio nova if separate genus recognised, first used in 1895 theodore sherman palmer.

stejneger s 1925 reconstruction of steller measuring sea cow in 1742

for decades after discovery, no skeletal remains of steller s sea cow discovered. may have been due rising , falling sea levels on course of quaternary period, have left many sea cow bones hidden. first bones of steller s sea cow unearthed in 1840, on 70 years after presumed extinct. first partial sea cow skull discovered in 1844 ilya voznesensky while on commander islands, , first skeleton discovered in 1855 on northern bering island. these specimens sent saint petersburg in 1857, , complete skeleton arrived in moscow around 1860. of skeletal remains unearthed in late 1800s: between 1878 , 1883, 12 of known 27 skeletons discovered. adolf erik nordenskiöld, benedykt dybowski, , leonhard hess stejneger each unearthed many bones different individuals during period, composite skeletons assembled. of 2006, 27 complete skeletons , 62 complete skulls have been found.

illustrations

the pallas picture known drawing of steller s sea cow believed actual specimen. published peter simon pallas in 1840 work icones ad zoographia rosso-asiatica. pallas did not specify source; stejneger suggested may have been 1 of original illustrations produced friedrich plenisner, member of vitus bering s crew painter , surveyor drew figure of female sea cow on steller s request. of plenisner s depictions lost during transit siberia saint petersburg.

another drawing of steller s sea cow similar pallas picture appeared on 1744 map drawn sven waxell , sofron chitrow. picture may have been based upon specimen, , published in 1893 pekarski. map depicted vitus bering s route during great northern expedition, , featured illustrations of steller s sea cow , steller s sea lion in upper-left corner. drawing contains inaccurate features such inclusion of eyelids , fingers, leading doubt drawn specimen.

johann friedrich von brandt, director of russian academy of sciences, had ideal image drawn in 1846 based upon pallas picture, , ideal picture in 1868 based upon collected skeletons. 2 other possible drawings of steller s sea cow found in 1891 in waxell s manuscript diary. there map depicting sea cow, steller sea lion , northern fur seal. sea cow depicted large eyes, large head, claw-like hands, exaggerated folds on body, , tail fluke in perspective lying horizontally rather vertically. drawing may have been distorted depiction of juvenile, figure bears resemblance manatee calf. similar image found alexander von middendorff in 1867 in library of russian academy of sciences, , copy of tsarskoye selo picture.