''Seppo'' is an extinct
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...
of
spider
Spiders ( order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species ...
s, possibly of the superfamily
Palpimanoidea
The Palpimanoidea or palpimanoids, also known as assassin spiders, are a group of araneomorph spiders, originally treated as a superfamily. As with many such groups, its circumscription has varied. , the following five families were included:
* A ...
, that lived about 180 million years ago, in the Early Jurassic (Lower
Toarcian
The Toarcian is, in the ICS' geologic timescale, an age and stage in the Early or Lower Jurassic. It spans the time between 182.7 Ma (million years ago) and 174.1 Ma. It follows the Pliensbachian and is followed by the Aalenian.
The Toarcian ...
) of what is now
Europe
Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a subcontinent of Eurasia and it is located entirel ...
. The sole species ''Seppo koponeni'' is known from a single fossil from
Grimmen
Grimmen (; csb, Grzëmié) is a town in Vorpommern-Rügen, a district in the Bundesland Mecklenburg-Vorpommern, Germany. Prior to 2011, when district reforms were made in Mecklenburg-Vorpommern, it was the capital of the now bygone Nordvorpomme ...
, Germany.
With the scorpion ''
Liassoscorpionides'', it is one of the two only known arachnids from the Lower Jurassic of
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 ...
.
[ ''Seppo'' is the first unequivocal Early Jurassic spider, and was recovered from the ''Green Series'' member of the ]Toarcian
The Toarcian is, in the ICS' geologic timescale, an age and stage in the Early or Lower Jurassic. It spans the time between 182.7 Ma (million years ago) and 174.1 Ma. It follows the Pliensbachian and is followed by the Aalenian.
The Toarcian ...
Ciechocinek Formation
The Ciechocinek Formation (also known as the Gryfice Formation at Suliszewo), formerly known in Germany as the Green Series (German: ''Grüne Serie'') is a Jurassic (lower Toarcian) geologic formation that extends across the Baltic coast, from ...
.[
]
Description
The spider was described from a single female specimen. It is unknown if was an adult.[ The carapace is unknown, and besides that has preserved bowed converging sides with a curved posterior margin with straight posterior border of the labium, with row of at least 12 peg teeth along the cheliceral furrow, no true teeth, scattered setae on anterior surface, and slender ]pedipalps
Pedipalps (commonly shortened to palps or palpi) are the second pair of appendages of chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") and ...
.[ Legs are preserved, the first and second being much longer than the third and fourth. All are well covered in setae and bristles, especially on the tibiae and metatarsi of leg I.][ It most likely belongs to the ]Palpimanoidea
The Palpimanoidea or palpimanoids, also known as assassin spiders, are a group of araneomorph spiders, originally treated as a superfamily. As with many such groups, its circumscription has varied. , the following five families were included:
* A ...
, based on the presence of cheliceral peg teeth.[
]
Discovery
The single known specimen was found on locality known for its fossil insects in Grimmen
Grimmen (; csb, Grzëmié) is a town in Vorpommern-Rügen, a district in the Bundesland Mecklenburg-Vorpommern, Germany. Prior to 2011, when district reforms were made in Mecklenburg-Vorpommern, it was the capital of the now bygone Nordvorpomme ...
, near Greifswald
Greifswald (), officially the University and Hanseatic City of Greifswald (german: Universitäts- und Hansestadt Greifswald, Low German: ''Griepswoold'') is the fourth-largest city in the German state of Mecklenburg-Western Pomerania after Rosto ...
, at the north of 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 ...
.[ It was reported in 2003, when Ansorge did a recompilation of insect taxa on the ]Toarcian
The Toarcian is, in the ICS' geologic timescale, an age and stage in the Early or Lower Jurassic. It spans the time between 182.7 Ma (million years ago) and 174.1 Ma. It follows the Pliensbachian and is followed by the Aalenian.
The Toarcian ...
strata of Germany and England
England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...
. The specimen was recovered from the Falciferum zone (Exaratum subzone), c. 180 Ma, and presented as "Araneae
Spiders (order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species dive ...
gen. et sp. nov." (Chelicerata
The subphylum Chelicerata (from New Latin, , ) constitutes one of the major subdivisions of the phylum Arthropoda. It contains the sea spiders, horseshoe crabs, and arachnids (including harvestmen, scorpions, spiders, solifuges, ticks, and mi ...
).[ It was recovered from a fragment of calcareous nodule from the grey-green claystone, recovered from the closed since the 90's clay pit of Klein Lehmhagen, near ]Grimmen
Grimmen (; csb, Grzëmié) is a town in Vorpommern-Rügen, a district in the Bundesland Mecklenburg-Vorpommern, Germany. Prior to 2011, when district reforms were made in Mecklenburg-Vorpommern, it was the capital of the now bygone Nordvorpomme ...
, Western Pomerania
Pomerania ( pl, Pomorze; german: Pommern; Kashubian: ''Pòmòrskô''; sv, Pommern) is a historical region on the southern shore of the Baltic Sea in Central Europe, split between Poland and Germany. The western part of Pomerania belongs to ...
, Germany.[ It is curious for being one of the rare few examples of spiders found on calcium carbonate (along with others from the ]Eocene
The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', " ...
limestone of the Isle of Wight
The Isle of Wight ( ) is a Counties of England, county in the English Channel, off the coast of Hampshire, from which it is separated by the Solent. It is the List of islands of England#Largest islands, largest and List of islands of England#Mo ...
, England
England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...
). The specimen was found with some parts preserved as external moulds, and these show seta
In biology, setae (singular seta ; from the Latin word for " bristle") are any of a number of different bristle- or hair-like structures on living organisms.
Animal setae
Protostomes
Annelid setae are stiff bristles present on the body. ...
tion and spination. This is an exception, since most of the specimen is an internal mould of calcium carbonate.[ The specimen was labeled with the number MB.A 2966, and deposited in the ]Museum für Naturkunde
The Natural History Museum (german: Museum für Naturkunde) is a natural history museum located in Berlin, Germany. It exhibits a vast range of specimens from various segments of natural history and in such domain it is one of three major muse ...
, Berlin
Berlin ( , ) is the capital and List of cities in Germany by population, largest city of Germany by both area and population. Its 3.7 million inhabitants make it the European Union's List of cities in the European Union by population within ci ...
, being named in 2014 by Paul A. Selden & Jason A. Dunlop ''Seppo koponeni'', after the Finnish arachnologist
Arachnology is the scientific study of arachnids, which comprise spiders and related invertebrates such as scorpions, pseudoscorpions, and harvestmen. Those who study spiders and other arachnids are arachnologists. More narrowly, the study of ...
, to celebrate his 70th birthday.[
]
Phylogeny
The genus was described as the oldest Palpimanoidea
The Palpimanoidea or palpimanoids, also known as assassin spiders, are a group of araneomorph spiders, originally treated as a superfamily. As with many such groups, its circumscription has varied. , the following five families were included:
* A ...
or the nearest sister taxon to the group. The exact familiar placement of the genus is unclear, as it was assigned to the family based on the presence of peg teeth, a synapomorphy
In phylogenetics, an apomorphy (or derived trait) is a novel character or character state that has evolved from its ancestral form (or plesiomorphy). A synapomorphy is an apomorphy shared by two or more taxa and is therefore hypothesized to hav ...
thought to be unique to the superfamily.[ However, recent revisions of modern spiders have shown that this character is also present in the ]Mimetidae
Pirate spiders, members of the family Mimetidae, are araneomorph spiders which typically feed on other spiders.
The family Mimetidae contains roughly 200 species divided among 12 genera, of which ''Mimetus'' and ''Ero'' are the most common. Mim ...
and other Entelegynae
The Entelegynae or entelegynes are a subgroup of araneomorph spiders, the largest of the two main groups into which the araneomorphs were traditionally divided. Females have a genital plate ( epigynum) and a "flow through" fertilization system; m ...
families.[ Early araneomorphs such as those in the clade Synspermiata and the families Filistatidae, ]Austrochilidae
Austrochilidae is a small spider family with nine species in two genera. ''Austrochilus'' and ''Thaida'' are endemic to the Andean forest of central and southern Chile and adjacent Argentina.
Taxonomy
, two genera are placed in the family Austr ...
and Leptonetidae
Leptonetidae is a relatively primitive family of spiders first described by Eugène Simon in 1890. It is made up of tiny haplogyne spiders, meaning they lack the hardened external female genitalia. Their six eyes are arranged in a semicircle of f ...
lack it, locating the genus as either a stem Palpimanoidea or a stem Entelegynae.[
]
Ecology
''Seppo koponeni'' is one of the only two arachnids ever to have been found in the Toarcian
The Toarcian is, in the ICS' geologic timescale, an age and stage in the Early or Lower Jurassic. It spans the time between 182.7 Ma (million years ago) and 174.1 Ma. It follows the Pliensbachian and is followed by the Aalenian.
The Toarcian ...
rocks of north Germany, outnumbered by several thousand insect specimens at several localities.[ The different between the number of insects as opposed to arachnids has not been studied in depth. A possibility is that because insects can fly over water, they fall into it far more easily than spiders.][ It is unclear how the spider ended on a marine clay deposit, far from the land, although several theories have been suggested: ]ballooning Ballooning may refer to:
* Hot air ballooning
* Balloon (aeronautics)
* Ballooning (spider)
* Ballooning degeneration, a disease
* Memory ballooning
See also
* Balloon (disambiguation)
A balloon is a flexible container for (partially or fully) co ...
is a possibility as a method of transport, perhaps helped by severe storms, hurricanes, and tornadoes.[ Another possibility might be that it was carried out to sea on floating vegetation, as wood remains have been recovered in the deposit.][
On nearby land, ground dwellers were represented by arachnids, such as ''Seppo'' and scorpions, but also by ]Gryllidae
The family ''Gryllidae'' contains the subfamilies and genera which entomologists now term true crickets. Having long, whip-like antennae, they belong to the Orthopteran suborder Ensifera, which has been greatly reduced in the last 100 years (''e ...
, such as '' Protogryllus dobbertinensis'', grylloblattodea
Grylloblattidae, commonly known as the icebugs, or ice crawlers, is a family of extremophile (psychrophile) and wingless insects that live in the cold on top of mountains and the edges of glaciers. They belong, along with Mantophasmatidae (rock c ...
ns such as '' Nele jurassica'', and dermapterans.[ These arthropods never moved far from where they lived and are generally very rare in the rocks.][ ''Seppo'' shows a rather unusual morphology, with large and porrect ]chelicerae
The chelicerae () are the mouthparts of the subphylum Chelicerata, an arthropod group that includes arachnids, horseshoe crabs, and sea spiders. Commonly referred to as " jaws", chelicerae may be shaped as either articulated fangs, or similarl ...
and a robust leg I, contrasted with a short leg III.[ The robust and well-armed first legs, directed forwards, give the impression that they were prey capture appendages, a morphology typical of a sit-and-wait predator, while the short third legs are more typical of web spiders, especially orbweavers, but also palpimanoids. Short third legs are not usually found on spiders that are substrate dwellers, which have more equal legs.][ ''Seppo'' was probably not a habitual ground dweller. The armoured front legs related to capturing dangerous prey are typical of many extant palpimanoids that are araneophagous.][
]
References
{{Taxonbar, from1=Q20722585, from2=Q24238763
Mesozoic arachnids
†
Fossils of Germany
Fossil taxa described in 2014
Jurassic arachnids
†