The Burgess Shale

Ovatiovermis cribratus

The “ovation” legged worm

Artistic reconstruction of Ovatiovermis cribratus. Danielle Dufault © ROM


Kingdom: Animalia
Phylum: Onychophora (Lobopodia)
Higher Taxonomic Assignment: Order Luolishaniida
Species name: Ovatiovermis cribratus

Ovatiovermis is one of a variety of lobopodian taxa from the Cambrian, which are early members of the lineage that gave rise to arthropods, and whose only modern survivors are onychophorans (velvet worms) and tardigrades (water bears). Lobopodians characteristically have annulated, unjointed bodies and bear soft limbs after which they are called: the lobopods. Ovatiovermis groups with Facivermis as a peculiar “unarmoured” lineage within the Order Luolishaniida, notably characterized by their thin spines arranged in chevrons and the differentiation of their body into functional regions for suspension-feeding (Caron & Aria 2017, 2020).

Described by: Caron and Aria
Description date: 2017

Ovatiovermis – from the Latin ovatio (ovation) and vermis (worm) owing to the inferred upward-reaching, limb-waving posture of these animals.
cribratus – from the Latin cribrare, to sieve.

Type Specimens: Holotype ROMIP 52707 and Paratype ROMIP 64006 at the Royal Ontario Museum, Toronto, Canada.
Other species:

Burgess Shale and vicinity: None

Other deposits: None

Age & Localities:

Middle Cambrian, Wuliuan stage, Bathyuriscus-Elrathina Zone of the Burgess Shale Formation (approximately 507 million years old).
Principal localities:

The Walcott Quarry on Fossil Ridge.

History of Research:

Brief history of research:

Although the first and most complete specimen was discovered in 1994 by one of the ROM expeditions, Ovatiovermis was not described until 2017 by Caron and Aria. The animal served to exemplify suspension-feeding strategies early in panarthropod evolution, and prompted an analysis of the extent and significance of such lifestyle among other lobopodians.



Ovatiovermis has a worm-like, tubular body divided into three sections: An anterior section with two pairs of very long lobopods bearing thin spines arranges in chevrons and ending in paired claws; a middle section with four pairs of similar but smaller lobopods; and a posterior section with three pairs of very stout lobopods ending in single strong claws. The head is small and bears a pair of simple visual organs and an eversible pharynx. The surface of the body is devoid of any sclerite or spine. Cuticular folds are visible in the space in between lobopods.


Only two specimens. The holotype specimen (ROMIP 52707) was collected in 1994 from bed assemblage −120 (about 1.2 m below the base of the original Walcott Quarry floor), which is distinct from other bed assemblages in that it has particularly well-preserved specimens across a range of taxa (92 species). The paratype specimen (ROMIP 64006) was found in 2016 by a guest on a guided hike to the Walcott Quarry and forwarded to Dr. Jean-Bernard Caron by the Parks Interpreter office.

Maximum Size:
Maximum Size: 25 mm.


Life habits: Epibenthic
Feeding strategies: Suspension feeder
Ecological Interpretations:

With its anterior sieving and posterior anchoring appendages, Ovatiovermis exemplifies suspension-feeding specialization among lobopodians. It was likely anchored to sponges and stood erect in the water to catch food particles or plankton.


  • CARON, J. and ARIA, C. 2020. The Collins’ monster, a spinous suspension‐feeding lobopodian from the Cambrian Burgess Shale of British Columbia. Palaeontology, 63, 979–994.
  • CARON, J.-B. and ARIA, C. 2017. Cambrian suspension-feeding lobopodians and the early radiation of panarthropods. BMC Evolutionary Biology, 17, 29.
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