We are fossil researchers who collect and study Scottish early Palaeozoïc fossils. The fossil site Birk Knowes SSSI has been our prime locality of interest due to the extremely well-preserved fossils occurring there. It has not been possible to carry out our work at this site since August 1995 because Scottish Natural Heritage has kept this fossil site closed. Below is some information about Birk Knowes, the fossils from there, and our work on the fossils.
The thelodont Loganellia scotica
Loganellia scotica is a member of an enigmatic group of jawless fishes called thelodonts. These fishes had a skin covering of tooth-like scales called denticles. Internal structures are rarely observed due to their denticle cover. At Birk Knowes this fish could be found partly- or entirely enclosed within a concretion. Concretions from Birk Knowes have a unique preservation capacity. By carefully etching split nodules with diluted acetic acid we encountered three types of internally situated denticle groups. The ones near the gill apparatus were fused into oblong tooth plates. Our discovery of tooth plates within a jawless fish has given rise to debate in the field of early vertebrates. Thelodonts are regarded by some as forerunners of fishes with jaws.
The enigmatic arthropod Ainiktozoon loganense
This enigmatic creature has been described in an extensive paper by Alex Ritchie (1985). We treated Ainiktozoon fossils contained within a concretion with acetic acid and also thin sectioned them. This revealed incredibly well-preserved soft tissue preservation, such as 3D muscles showing even the sarcomeres. Together with David Martill and Fred Schram we found out that Ainiktozoon was previously reconstructed upside-down and that it is was not a proto-chordate, but in fact a predatory arthropod (see below). Much of the anatomy of this arthropod remains poorly understood, but further work is not possible due to the closure of the site.
The enigmatic fish Jamoytius kerwoodi
Jamoytius is a poorly-understood jawless fish. An intact specimen has never been found and the reconstruction by Alex Ritchie (below) is partly hypothetical. This fish is probably a member of the Euphaneropidae, a group of fishes from the Silurian and Devonian known from one area in Canada, and two other areas in Scotland. We are specialised in this group of fishes. New material is needed to better the understanding of Jamoytius.
The pod shrimp Ceratiocaris papilio
This is a pod shrimp and the most abundant macrofossil at Birk Knowes. It occurs throughout the Patrick Burn Formation in great amounts, but at Birk Knowes its preservation is exceptional. The (seemingly) only specimens with appendages are from this locality. To the right is one such specimen in our collection. Though much work on this pod shrimp was done by Ian Rolfe (1963), there are still a few questions to be solved.
Throughout the Jamoytius Horizon several nodule beds occur which mainly yield Ceratiocaris and thelodont remains. We regard these beds as mass-mortality events. What were the bottom conditions like that caused these fossils to be enveloped in nodules? Another remarkable thing is that the nodules contain an abundance of yet-unnoticed fossilised micro-organisms.
The most stunning aspect of this locality is the exceptional preservation of soft tissues, which is our discovery. This is a rarity for fossils, as typically only hard tissues are preserved. At Birk Knowes, not only are soft tissues preserved, but they are at times immaculate, as though the animal turned to stone. The soft tissues are three-dimensionally preserved, as seen below.
Below are some of our peer reviewed publications about fossils from this site and fossils related to those occurring at Birk Knowes.
- van der Brugghen, W. & Janvier, P. 1993. Denticles in thelodonts. Nature 364: 107.
- van der Brugghen, W., Schram, F. & Martill, D. 1997. The fossil Ainiktozoon is an arthropod. Nature 385: 589-590.
- van der Brugghen, G. 2015. Ciderius cooperi gen. nov., sp. nov., the earliest known euphaneropid from the Lower Silurian of Scotland. Netherlands Journal of Geosciences 94 (3): 279–288.
- van der Brugghen, G. 2017. Taphonomy versus taxonomy and the synonyms of Euphanerops longaevus Woodward, 1900 (Agnatha) occurring at the Middle Devonian Devonian Achanarras Quarry of Caithness, Scotland. Neues Jahrbuch für Geologie und Paläontologie 286 (3): 329–347.
Some non-peer reviewed articles on Birk Knowes fossils and related Silurian fossils from Scotland.
- Van der Brugghen, W. 1992. Vondstmelding van gefuseerde schubben in een Loganellia cf scotica. (Discovery note on fused denticles inside a Loganellia scotica) Grondboor en Hamer; Ichthyolith Issues.
- Van der Brugghen, W. 1993. Thelodonten binnenste buiten gekeerd (Thelodonts turned inside out). Grondboor en Hamer; Ichthyolith Issues.
- Van der Brugghen, W. 1994. Over magen en staarten van thelodonten (About stomachs and tails of thelodonts). Grondboor en Hamer.
- Van der Brugghen, W. 1995. Dictyocaris, een enigmatisch fossel uit het Siluur (Dictyocaris, an enigmatic Silurian fossil). Grondboor en Hamer.
- Van der Brugghen, W. 1997. Het raadsel Ainiktozoon opgelost (The riddle Ainiktozoon solved). Grondboor en Hamer.
- Van der Brugghen, W. en G.S., 2000. Verzamelbeperkingen leidden tot de vondst van ‘nieuwe’ Silurische agnathen en ander belangrijk materiaal (Collecting restrictions lead to the discovery of ‘new’ Silurian agnathans and other important material.) Grondboor en Hamer.
- Van der Brugghen, W. 2002. Enige bijzondere kaakloze vissen (Agnatha) uit het Onder-Siluur van Lanarkshire (Schotland). (Some remarkable jawless fishes (Agnatha) from the Lower-Silurian of Lanarkshire (Scotland)). Grondboor en Hamer.
- Van der Brugghen, W. 2006. Ceraticaris papilio, een garnaalachtig fossiel met vraagtekens. (Ceratiocaris papilio, a podshrimp with question marks) Grondboor en Hamer.