Attockicetus

Attockicetus Temporal range: Eocene PreЄ Є O S D C P T J K Pg N
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Cetacea
Family:	Remingtonocetidae
Genus:	Attockicetus Thewissen & Hussain 2000
Binomial name
Attockicetus praecursor (type) Thewissen & Hussain 2000

Attockicetus is an extinct genus of remingtonocetid early whale known from the Middle Eocene (Lutetian) Kuldana Formation in the Kala Chitta Hills, in the Attock District of Punjab, Pakistan.^[1]

Thewissen & Hussain 2000 described Attockicetus based on fragmentary cranial material. Their specimen includes a fragmentary rostrum, an endocast (interior of cranium), and an ectotympanic (ear bone). The specimen also had preserved cheek teeth, P³-M³, which is rare in remingtonocetids. Attockicetus is primitive in the retention of large protocones on the upper molars and the location of the orbits anteriorly on the skull. It is probably the most plesiomorphic remingtonocetid^[2]

Cooper, Thewissen & Hussain 2009 collected additional dental material at the type locality which they assigned to Attockicetus. Compared to pakicetid teeth found at the same locality, the P₃ of Attockicetus is much lower, angled anteriorly, and has a very long posterior extension. A long diastema separates P₃ from P₄ and P₃ is longer than P₄, which Cooper et al. identified as a remingtonocetid character and, because Attockicetus is the only known remingtonocetid known from the Kala Chitta Hills, they tentatively assigned the specimen as belonging to this genus. The P₄ of Attockicetus is similar to those of Pakicetus in retaining a tall protoconid (cusp) and anterior and posterior basal extensions with prominent cristae (crests), but differs from them in having steeper protoconid slopes, being taller, and having longer basal extensions. Cooper et al. also noted that the molar wear in pakicetids is typically extensive, whilst the P₄ in Attockicetus is less worn, suggesting that the latter was not used for breaking down food, but for holding prey.^[1]

Notes

1. Cooper, Thewissen & Hussain 2009, pp. 1296–8
2. Thewissen & Hussain 2000, Abstract

References

• Cooper, Lisa Noelle; Thewissen, J. G. M.; Hussain, S. T. (2009). "New middle Eocene archaeocetes (Cetacea: Mammalia) from the Kuldana Formation of northern Pakistan". Journal of Vertebrate Paleontology 29 (4). doi:10.1671/039.029.0423.
• Thewissen, J. G. M.; Hussain, S.T. (2000). "Attockicetus praecursor, a new remingtonocetid cetacean from marine Eocene sediments of Pakistan". Journal of Mammalian Evolution 7 (3): 133–46. doi:10.1023/A:1009458618729. OCLC 362777268.