''Mesolimulus'' is an extinct genus of
horseshoe crab
Horseshoe crabs are marine and brackish water arthropods of the family Limulidae and the only living members of the order Xiphosura. Despite their name, they are not true crabs or crustaceans: they are chelicerates, most closely related to ar ...
. 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
Bavaria ( ; ), officially the Free State of Bavaria (german: Freistaat Bayern, link=no ), is a state in the south-east of Germany. With an area of , Bavaria is the largest German state by land area, comprising roughly a fifth of the total lan ...
,
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
. Originally assigned to the living genus ''
Limulus
''Limulus'' is a genus of horseshoe crab, with one extant species, the Atlantic horseshoe crab (''Limulus polyphemus''). One fossil species is currently assigned to the genus though several other species have been named, which have since been as ...
'', 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
In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided in chronostratigraphy. The Middle Triassic spans the time between Ma and ...
to
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...
from England, Spain,
Siberia
Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive region, geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a ...
and Morocco.
Kouphichnium
The unusual
trackway
Historic roads (historic trails in USA and Canada) are paths or routes that have historical importance due to their use over a period of time. Examples exist from prehistoric times until the early 20th century. They include ancient trackways ...
s left by these animals at Solnhofen were originally thought to have been made by
birds or
pterosaurs, 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
The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya.
Th ...
, more than 440 million years ago, and late
Paleozoic
The Paleozoic (or Palaeozoic) Era is the earliest of three geologic eras of the Phanerozoic Eon.
The name ''Paleozoic'' ( ;) was coined by the British geologist Adam Sedgwick in 1838
by combining the Greek words ''palaiós'' (, "old") and ' ...
''
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 (
Bathonian
In the geologic timescale the Bathonian is an age and stage of the Middle Jurassic. It lasted from approximately 168.3 Ma to around 166.1 Ma (million years ago). The Bathonian Age succeeds the Bajocian Age and precedes the Callovian Age.
Str ...
)
Talynzhansk Formation, Russia
* ''Mesolimulus tafraoutensis'' Lamsdell et al., 2020
Late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...
(upper
Cenomanian –lower
Turonian
The Turonian is, in the ICS' geologic timescale, the second age in the Late Cretaceous Epoch, or a stage in the Upper Cretaceous Series. It spans the time between 93.9 ± 0.8 Ma and 89.8 ± 1 Ma (million years ago). The Turonian is preceded b ...
) Gara Sbaa Lagerstatte, Morocco
* ''Mesolimulus walchi'' (Desmarest, 1822)
Late Jurassic
The Late Jurassic is the third epoch of the Jurassic Period, and it spans the geologic time from 163.5 ± 1.0 to 145.0 ± 0.8 million years ago (Ma), which is preserved in Upper Jurassic strata.Owen 1987.
In European lithostratigraphy, the name ...
(
Kimmeridgian
In the geologic timescale, the Kimmeridgian is an age in the Late Jurassic Epoch and a stage in the Upper Jurassic Series. It spans the time between 157.3 ± 1.0 Ma and 152.1 ± 0.9 Ma (million years ago). The Kimmeridgian follows the Oxford ...
–Early
Tithonian)
Solnhofen Limestone, Germany
* ''Mesolimulus woodwardi'' (Watson, 1909) Middle Jurassic (
Aalenian
The Aalenian () is a subdivision of the Middle Jurassic Epoch/Series of the geologic timescale that extends from about 174.1 Ma to about 170.3 Ma (million years ago). It was preceded by the Toarcian and succeeded by the Bajocian.
Stratigraphi ...
)
Northampton Sand Formation
The Northampton Sand Formation, sometimes called the Northamptonshire Sand, is a Middle Jurassic geological formation which is placed within the Inferior Oolite Group. It was formerly worked extensively in Northamptonshire for its ironstone.
Th ...
, England
* ''Mesolimulus'' ''crespelli'' Vıa Boada, 1987
Middle Triassic
In the geologic timescale, the Middle Triassic is the second of three epochs of the Triassic period or the middle of three series in which the Triassic system is divided in chronostratigraphy. The Middle Triassic spans the time between Ma and ...
(
Ladinian
The Ladinian is a stage and age in the Middle Triassic series or epoch. It spans the time between Ma and ~237 Ma (million years ago). The Ladinian was preceded by the Anisian and succeeded by the Carnian (part of the Upper or Late Triassic ...
)
Alcover Limestone Formation, 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
