''Mesolimulus'' is an extinct genus of
horseshoe crab. The best known examples are found in
Solnhofen limestone near
Solnhofen
Solnhofen is a municipality in the district of Weißenburg-Gunzenhausen in the region of Middle Franconia in the ' of Bavaria in Germany. It is in the Altmühl valley.
The local area is famous in geology and palaeontology for Solnhofen limest ...
,
Bavaria,
Germany. Originally assigned to the living genus ''
Limulus'', they are related to and look virtually identical to modern horseshoe crabs. Other species assigned to ''Mesolimulus'' have been recorded spanning over 140 million years from the
Middle Triassic to
Late Cretaceous from England, Spain,
Siberia and Morocco.
Kouphichnium
The unusual
trackways left by these animals at Solnhofen were originally thought to have been made by
birds
Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweigh ...
or
pterosaurs
Pterosaurs (; from Greek ''pteron'' and ''sauros'', meaning "wing lizard") is an extinct clade of flying reptiles in the order, Pterosauria. They existed during most of the Mesozoic: from the Late Triassic to the end of the Cretaceous (228 to ...
, since they included a cross-shaped marking comparable with the impression of a typical bird foot. Eventually they were correctly identified as arthropod footprints and named ''Kouphichnium walchi'', as proved by some remarkable 'death traces' showing a ''Mesolimulus'' circling round on itself before dying. The last leg of more advanced horseshoe crabs is modified into a so-called 'pusher' which consists of four plates at the tip which push against the soft sediment rather like a snow-shoe. This was what left the unusual bird-like footprints.
Horseshoe crabs in general date to the
Ordovician Period, more than 440 million years ago, and late
Paleozoic ''
Euproops'' fossils indicate that they have changed little over the last 300 million years. Fossils preserved in Solenhofen limestone are unusual because soft body parts and skeletons are clearly represented.
Species
After
* ''Mesolimulus sibiricus'' Ponomarenko, 1985,
Middle Jurassic
The Middle Jurassic is the second epoch of the Jurassic Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively rare, but geological formations co ...
(
Bathonian)
Talynzhansk Formation, Russia
* ''Mesolimulus tafraoutensis'' Lamsdell et al., 2020
Late Cretaceous (upper
Cenomanian
The Cenomanian is, in the ICS' geological timescale, the oldest or earliest age of the Late Cretaceous Epoch or the lowest stage of the Upper Cretaceous Series. An age is a unit of geochronology; it is a unit of time; the stage is a unit in the s ...
–lower
Turonian) Gara Sbaa Lagerstatte, Morocco
* ''Mesolimulus walchi'' (Desmarest, 1822)
Late Jurassic (
Kimmeridgian –Early
Tithonian
In the geological timescale, the Tithonian is the latest age of the Late Jurassic Epoch and the uppermost stage of the Upper Jurassic Series. It spans the time between 152.1 ± 4 Ma and 145.0 ± 4 Ma (million years ago). It is preceded by the K ...
)
Solnhofen Limestone, Germany
* ''Mesolimulus woodwardi'' (Watson, 1909) Middle Jurassic (
Aalenian)
Northampton Sand Formation, England
* ''Mesolimulus'' ''crespelli'' Vıa Boada, 1987
Middle Triassic (
Ladinian)
Alcover Limestone Formation
Alcover is a municipality in the ''comarca'' of Alt Camp, Tarragona, Catalonia, Spain.
The Prades Mountains are located in the vicinity of this municipality.
It is the birthplace of the footballer Kiko Casilla
Francisco "Kiko" Casilla Cortà ...
, Spain
References
* Caster, K. E. 1941. Trails of ''Limulus'' and supposed vertebrates from Solnhofen lithographic limestone. ''Pan-American Geologist'', 76:241–258.
* Malz, H. 1964. ''Kouphichnium walchi'', die Geschichte einer Fährte und ihres
Tieres. ''Natur und Museum'', 94:81–97.
Solnhofen fauna
Xiphosura
Late Jurassic arthropods
{{paleo-arthropod-stub