Sacabambaspis janvieri

Overview

Sacabambaspis janvieri is an Ordovician vertebrate. Even small fragments of its hard dermal skeleton can be studied. Researchers analysed the layers and spaces inside these fragments to investigate tissues that are not visible from the outside.^[1]

Key facts

The dermal bone can be divided into a layered base, a middle layer with large spaces, and an upper layer with surface ridges. It is intriguing that even a small fragment contains different tissues arranged layer upon layer.^[1]

Time and place

A 2005 study examined Ordovician material from South America. The specimens came from the Anzaldo Formation in Cochabamba, present-day Bolivia, and the Sepulturas Formation in Jujuy, Argentina.^[1]

The time range describes source context, not the complete duration of this species.

Size, form and skeleton

Vertical supports in the middle layer surround large spaces. Thin layers lie stacked below, while the ridges on the upper surface have a covering of hard tissue called enameloid.^[1]

Sacabambaspis is presented as a fish about 35 cm long. Picture a slender body and tail extending behind a flat, hard head.^[6]

Habitat and reproduction

The researchers compared the hard surface layer of the body covering with the layer containing numerous passages below it. This research explores the tissues that made up a living animal through small arrangements inside its bones.^[1]

Fossil discovery

The researchers cut bone fragments into thin sections to transmit light through them or examined them with an electron microscope. CORD-MP9101 and MHNC13261 are separate specimens that provided material for comparing tissue structure in the same species.^[1]

References

1. Sansom et al. (2005) — A look inside the three layers of dermal bone
2. Sansom et al. (2005) — A look inside the three layers of dermal bone
3. Dearden et al. (2023) — Cranial cartilage of ancient vertebrates examined with CT
4. Wilson·Märss (2012) — Phlebolepis reconstructed from hundreds of fossils
5. Sansom et al. (2005) — A look inside the three layers of dermal bone
6. Okinawa Institute of Science and Technology — Sacabambaspis
7. Pradel et al. (2007) — The tail of the Ordovician fish Sacabambaspis

Research questions

The Bolivian and Argentine material underwent different changes during preservation. Nevertheless, the tissue arrangements corresponded between the two localities, providing the researchers with a basis for comparing relationships among early vertebrates.^[1]

Observation

Inferred life reconstruction. Look at the flattened upper head, swollen underside and long tail extension. Colour, pattern, soft tissues and pose are inferred; the illustration is not for measurement.^[7]