Tomial Teeth in shrikes

posted in: Morphology-Develop. | 2

“I am grateful to Mike Rose, a bird watching colleague based in Thailand, who first pointed out this feature on a twitter post. Although I have occasionally seen tomial teeth in shrikes, I had not questioned its relevance.

ShrikeBr-tomial tooth [AmarSingh]

“Tomial ‘teeth’ are ‘ventral projections along the rostral tomium of the rhamphotheca‘ [see Sustaita (2014), Cade (1995), Schön (1996)]. These of course are not real ‘teeth’ and are not coated in enamel but keratin. They can be easily missed in the field except at close range.

ShrikeBr-tomial tooth [AmarSingh]

“The corresponding indentations in the lower mandible are even harder to appreciate. I looked through many of my images of shrikes and found some passable close-ups that show the feature. The above two images are of Brown Shrikes (Lanius cristatus).

ShrikeTg-tomial tooth [AmarSingh]

“The above image is of a Tiger Shrike (Lanius tigrinus) and below of a Long-tailed Shrike (Lanius schach bentet).

ShrikeLT-tomial tooth [AmarSingh]

“Lefranc (1997) describes the feature in Lanius shrikes: they have ‘raptor-like billsThe upper mandible shows a subterminal tominal tooth on each side and the lower mandible has corresponding incurvations. This shape bears strong resemblance to that of falcons…’

“‏Karen McDonald (2014) when describing tomial teeth in raptors says ‘the tomial tooth (pl. mandibular tomia) is the outer, or cutting edge of the beak. This ‘tooth’ is the protrusion that extends from the tomial edge of the beak and is thought to be used to deliver the killing blow to prey (severs the spinal cord). The tomial tooth of the upper mandible is often matched by a mandibular notch, or divot, in the lower mandible…. Other birds of prey may show some slight tomial indentations but not to the extent that falcons, kites, and accipiters do.’

“A number of on-line article have described tomial teeth in shrikes as being used to ‘sever the spinal cord’ or ‘deliver the killing stroke‘ with some offering detailed work on issues, see for example Sustaita (2014).”

Diego Sustaita, Margaret A. Rubega (2014). The anatomy of a shrike bite: bill shape and bite performance in Loggerhead Shrikes. Biological Journal of the Linnean Society. 112, 485-498. See: LINK
2. Cade TJ (1995). Shrikes as predators. Proceedings of the Western Foundation of Vertebrate Zoology 6: 1-5.
3. Schön M (1996). Raptor-like passerines – some similarities and differences of shrikes (Lanius) and raptors. Oekologie der Voegel 18: 173-216.
4. Norbert Lefranc (1997). Shrikes: A Guide to the Shrikes of the World (Helm Identification Guides), Yale University Press.
5.Tiger Karen McDonald (2014). Featured Feature: Tomial Teeth and Cranial Kinesis. See:

Dato’ Dr Amar-Singh HSS
Ipoh, Perak, Malaysia
7th February 2018

Follow YC Wee:

Dr Wee played a significant role as a green advocate in Singapore through his extensive involvement in various organizations and committees: as Secretary and Chairman for the Malayan Nature Society (Singapore Branch), and with the Nature Society (Singapore) as founding President (1978-1995). He has also served in the Nature Reserve Board (1987-1989), Nature Reserves Committee (1990-1996), National Council on the Environment/Singapore Environment Council (1992-1996), Work-Group on Nature Conservation (1992) and Inter-Varsity Council on the Environment (1995-1997). He is Patron of the Singapore Gardening Society and was appointed Honorary Museum Associate of the Lee Kong Chian Natural History Museum (LKCNHM) in 2012. In 2005, Dr Wee started the Bird Ecology Study Group. With more than 6,000 entries, the website has become a valuable resource consulted by students, birdwatchers and researchers locally and internationally. The views and opinions expressed in this article are his own, and do not represent those of LKCNHM, the National University of Singapore or its affiliated institutions.

2 Responses

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.