The Rhynie Chert Fauna

The Rhynie Chert Fauna:

A general list of the fauna together with illustrations

The following is a list of the Rhynie chert arthropod fauna that have been described to date. A controversial arthropod known from the remains of a single specimen, Rhyniognatha hirsti (Tillyard 1928), is now believed to be closely related to the pterygote insects based on the structure of it's mandibles (Engel & Grimaldi 2004). Also included for completeness is an arthropod of uncertain affinities; Rhynimonstrum dunlopi (Anderson & Trewin 2003). Discoveries of new elements of the Rhynie fauna have recently been made, and once described and published with be added to this list in due course.

Click on the image thumbnails for a close up:

Arthropod Group	Species Described from the Rhynie chert	Useful Texts	General Features	Palaeoecology	Image
Trigonotarbids	Palaeocharinus rhyniensis Palaeocharinus hornei Palaeocharinus tuberculatus *Palaeocteniza crassipes	Hirst 1923; Dunlop 1994, 1996b, Shear et al. 1987; Selden et al. 1991; Fayers et al. 2004	Extinct arachnids similar in appearance to spiders but lacking spinnerets and possessing a segmented abdomen.	Predator, living in terrestrial habitats. Often found in plant-rich beds, occasionally within empty sporangia and hollow plant stems.
Harvestmen	Eophalangium sheari	Dunlop et al. 2003, 2004	Arachnids lacking a distinct division between the head and body, with a segmented abdomen. Typically possess a small ovoid body with long slender legs.	Predator / saprovore / detritivore, living in damp terrestrial habitats, mostly in plant litter.
Mites	Protacarus crani Protospeleorchestes pseudoprotacarus Pseudoprotacarus scoticus Palaeotydeus devonicus Paraprotocarus hirsti	Hirst 1923; Dubinin 1962; Bernini 1986	Very small arachnids that lack a distinct division between the head and the body and have a smooth abdomen.	Micro-herbivore / saprovore, living in damp terrestrial habitats, primarily in plant litter and soil. Some probably also fed on sap from living plants. Occasionally found within empty sporangia.
Myriapods	Crussolum sp.	Shear et al. 1998; Anderson & Trewin 2003	A centipede similar to the modern house centipede, possessing strong poison jaws or 'forcipules', long antennae and 15 pairs of long multi-segmented walking legs.	Active predator, living in damp terrestrial habitats, such as in soils, plant litter and under stones.
Myriapods	Leverhulmia mariae	Anderson & Trewin 2003	A small myriapodous arthropod with at least 5 pairs of walking legs, each with densely crowded hairs or setae on the posterior of the last (tarsal) segment.	Saprovore / detritivore, living in damp terrestrial habitats, most probably in plant litter.
Hexapods	Rhyniella praecursor	Hirst & Maulik 1926; Tillyard 1928; Scourfield 1940a,b; Whalley & Jarzembowski 1981	A springtail (Collembola), with 3 pairs of legs, an abdomen of 6 segments, possessing a furcula or jumping organ on the 4th abdominal segment and a curious ventral tube on the 1st abdominal segment.	Saprovore, living in damp terrestrial habitats, particularly in plant litter and soil.
Hexapods	Rhyniognatha hirsti	Hirst & Maulik 1926, Tillyard 1928, Engel & Grimaldi 2004	The earliest known pterygote insect. Known only from the fragmentary mouthparts of one specimen, comprising a pair of robust mandibles with bladed tooth-like structures. Although fossil evidence is so far lacking, Rhyniognatha may have possessed primitive wings.	Comparing the jaws with those of modern insects, Rhyniognatha may have fed on higher plant tissues.
Crustaceans	Lepidocaris rhyniensis	Scourfield 1926 1940c	A small multi-segmented crustacean with 10 pairs of biramous leaf-like trunk appendages, long biramous antennae with plumose setae and lacking a cephalic shield in adults. Maxillae modified and look like the first 2 pairs of trunk limbs.	Micro-herbivore / detritivore, living in ephemeral freshwater ponds.
Crustaceans	Castracollis wilsonae	Fayers & Trewin 2003	8mm long, multisegmented crustacean. Thorax of up to 26 somites, each bearing legs. Up to 28 apodous abdominal segments. 2 series of thoracic legs. Anterior series: 11 pairs of long raptorial legs. Posterior series: 10-15 pairs of smaller phyllopodous legs. Head with large mandibles and long, symmetrical, biramous second antennae.	Similar to modern Tadpole Shrimps - detritivore / carnivore, living in ephemeral freshwater ponds.
Euthycarcinoids	Heterocrania rhyniensis	Hirst & Maulik 1926; Anderson & Trewin 2003	Multi-segmented arthropod sharing features with crustaceans and myriapods. Body comprises 5 large dorsal segments, each with 2 corresponding ventral segments that bear a pair of multi-segmented legs.	Micro-herbivore / detritivore, living in ephemeral freshwater ponds.
Arthropoda incertae sedis
Arthropoda incertae sedis	Rhynimonstrum dunlopi	Anderson & Trewin 2003	Articulated tubular segments of cuticle, the leading edge of each with a ring of sockets for spines or setae. Sometimes associated with sheets of punctate cuticle and clusters of long robust setae.	Unknown

*Note: A single specimen of a tiny arachnid described from the chert by Hirst (1923), Palaeocteniza crassipes, as being related to modern trap-door spiders is now regarded as a juvenile trigonotarbid (Selden et al. 1991).