Promyrmekiaphila korematsui: A new species of Trapdoor Spider from California.

Cryptic species are species which resemble one-another physically yet are reproductively isolated from each other. While such species clusters can come about due to convergent evolution, the vast majority are closely related species which have become reproductively isolated, but which have not diverged morphologically, usually as a result of a physical barrier splitting a population, followed by genetic drift. This is particularly common among morphologically conservative groups with low distribution rates, such as Mygalomorphs (Tarantulas, Trapdoor Spiders etc.), which are large Spiders occupying silk-lined burrows, typically remaining at a single site for their entire lives. 

In a paper published in the journal Ecology and Evolution on 1 March 2024, James Starrett, Emma Jochim, Iris Quayle, Xavier Zahnle, and Jason Bond of the University of California, Davis, present the results of a genetic study of the Trapdoor Spider genus Promyrmekiaphila, which is known only from California, and describe a new species, the third within the genus.

The genus Promyrmekiaphila was first described in 1950 by the Swiss arachnologist and herpetologist Ehrenfried Schenkel to describe a morphotype of Trapdoor Spider found across California, which he named Promyrmekiaphila gertschi. This was later found to have previously been described by the French naturalist Eugène Simon as Aptostichus clathratus in 1891, though it was later recognised that the assignation of the species to the genus Aptostichus was wrong, and Schenkel's name Promyrmekiaphila was adopted, leading to the combination Promyrmekiaphila clathratus.

In 2007 and 2008 Amy Stockman and Jason Bond, then both at the Department of Biology at East Carolina University, carried out a study of the population of Promyrmekiaphila clathratus using mitochondrial DNA (mtDNA), coming to the conclusion that there were in fact two species within the genus, Promyrmekiaphila clathratus found throughout the coastal ranges in central and northern California, and a new species, which they named Promyrmekiaphila winnemem, which was found at the northern end of the Central Valley. 

However, Stockman and Bond recognised that a study based upon mtDNA alone had its limitations, and that there still remained the possibility of other, cryptic, species of Promyrmekiaphila being found in California. 

Starrett et al.'s new study is based upon a wider gene set. This identified a number of deeply separated lineages within the Promyrmekiaphila clathratus  population, although Starrett et al. decline to name these as new species at this time, reasoning that they are not yet sufficiently genetically different to be reproductively isolated. However, a small group of Spiders found close to the San Andreas Fault line, from mid-San Francisco Peninsula to the Diablo Range, east of Paicines, were found to comprise a sister group to the Promyrmekiaphila clathratus and Promyrmekiaphila winnemem pair, therefore clearly representing a new species.

This new species is named Promyrmekiaphila korematsui, in honour of Fred Toyosaburo Korematsu, who  was awarded the United States Presidential Medal of Freedom in 1998 in recognition of his lifelong dedication as a civil rights activist and his resistance to the  incarceration of Japanese Americans in concentration camps during World War II.

Promyrmekiaphila korematsui, male live habitus photographs, side and dorsal views. Starrett et al. (2024).

Promyrmekiaphila korematsui is found d in shaded ravines and along roadcuts in Oak woodland habitat. Its distribution overlaps with that of Promyrmekiaphila clathratus, which may have implications for evolution of the genus, although the small sample size available for the genus so far prevents any detailed  analysis at this time.

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Megamonodontium mccluskyi: A new species of Brush-footed Trapdoor Spider from the Miocene of New South Wales.

Mygalomorph Spiders (Tarantulas and related species) are considered to be one of the most ancient groups of Spiders. They have two pairs of book lungs (many other Spiders have lost a pair) and downward pointing, rather than opposable fangs, again considered to be a primitive state in Spiders. Many species of Mygalomorph attain large sizes, all have flattened, disk-shaped bodies (rather than the more globular bodies of most other Spiders), and most are ambush predators.

These Spiders are known to have been present in Australia since before the break-up of Gondwana, with twelve families of Mygalomorphs found there today. Unfortunately, only a single fossil Mygalomorph has been described from Australia to date, Edwa maryae from the Triassic of Queensland, probably due to a combination of these Spiders both having fragile bodies unlikely to be preserved as fossils, and living in an environment unlikely to favour preservation (burrows, mostly in dry areas). Because of this, our understanding of the evolutionary history of Mygalomorph Spiders in Australia is based entirely upon phylogenetic analysis of extant species. By combining these phylogenetic studies with molecular clock analyses, it has been suggested that the group went through a significant evolutionary radiation during the Miocene, which coincides with a period of rapidly changing climate in Australia, with the rainforests which had covered much of the continent being replaced by the arid environment we see today. 

Within the Mygalomorphae as a whole, Brush-footed Trapdoor Spiders, Barychelidae, are considered to be the sister group to the True Tarantulas, Theraphosidae, differing from them in being smaller, having shorter spinnerets, and possessing tufts of setae on their feet which enable them to climb smooth surfaces. Brush-footed Trapdoor Spiders are found across all the major landmasses of the former Gondwana, with the exception of Antarctica and New Zealand, but are at their most diverse in Australia, which has led to the suggestion that they might have originated there. However, the most basal genus within the group, Monodontium, is not found in Australia, being found in Singapore, Borneo, and Papua New Guinea, where they inhabit Diptocarp rainforest environments. Members of the genus Monodontium are small for Mygalomorphs, and can be distinguished by the possession of biserial dentition of the paired claws in females, something only present in males in other genera.

In a paper published in the Zoological Journal of the Linnean Society on 15 September 2023, Matthew McCurry of the Australian Museum Research Institute, the Earth & Sustainability Science Research Centre at the University of New South Wales, and the Smithsonian National Museum of Natural History, Michael Frese, also of the Australian Museum Research Institute, and of the Commonwealth Scientific and Industrial Research Organisation, and the Faculty of Science and Technology at the University of Canberra, and Robert Raven of the Biodiversity and Geosciences Program at the Queensland Museum, describe a new species of Brush-footed Trapdoor Spider from the Miocene (16-11 million years old) McGraths Flat fossil sitet located  about 25 km north-east of Gulgong in New South Wales.

The new species is described from a single compressed specimen, AM F.145559, preserved as part and counterpart in a finely bedded goethite matrix. It is named Megamonodontium mccluskyi, where 'Megamonodontium' is a combination of the modern genus Monodontium, which it closely resembles, plus 'Mega', meaning 'very big', a reference to the specimen being five times the size of the largest known member of the genus Monodontium, while 'mccluskyi' honours Simon McClusky, who found the specimen.

Part (A) and counterpart (B) of Megamonodontium mccluskyi (AM F.145559). McCurry et al. (2023).

The specimen is split through the  carapace and abdomen, so that the chelicerae, eyes, fovea, sternum and spinnerets are unknown, while the e distal ends of the first, third and fourth legs are present only in it the part. This means that it was only realistic to examine the legs of the specimen when attempting to classify it, although this was certainly sufficient to place the specimen within the Barychelidae, based upon the legs being of similar thickness, an absence if strong spines on the first two pairs of legs, a reduced third, or middle, claw on all legs, and the presence of pads around the claws. The specimen lacks claw tufts, a distinguishing feature of the Brush-footed Trapdoor Spiders, but this has only ever been observed in fossil specimens preserved in amber, and therefore cannot be considered significant. 

While Megamonodontium mccluskyi superficially resembles some modern Australian Brush-footed Trapdoor Spiders, it retains a number of primitive features not seen in any of these, such as a long patella and teeth on the tarsal claw, making it most likely to be a close relative of the genus Monodontium. However, unlike the tiny Monodontium, Megamonodontium mccluskyi is a moderately large Spider with a carapace length of about 10 mm, making it the second largest fossil Spider ever discovered (behind the 24.6 mm Mongolarachne jurassica from the Jurassic of China).

Neither Megamonodontium nor Monodontium is found in Australia today, suggesting that if they do forma single clade, that clade has since become extinct in Australia. Moreover, the modern Monodontium lives in rainforest environments similar to those which would have been found around McGraths Flat when the fossil-bearing strata there were deposited. Since that time the Australian climate has changed, and the environment become dominated by dryland species such as Casuarina and Eucalyptus. The Miocene is known to have been a major interval for species turnover among Vertebrates, largely as a response to this changing climate, and molecular clock evidence has suggested that the same was true for Mygalomorph Spiders, but the absence of Spider fossils has made it impossible to determine if this was true from direct evidence until now.

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Pionothele gobabeb: A new species of Funnel-web Tarantula from Namibia.

Trapdoor Spiders are Mygalomorph Spiders (Spiders that lack opposable fangs, the same group as the Tarantulas) noted for the habit of excavating a burrow which they cover with a circular trapdoor, emerging from this to seize prey. They were formerly assumed to be a single taxonomic group, but the advent of molecular phylogenetic methods has revealed that several different Mygalomorph groups have independently evolved this lifestyle. The Nemesiidae are a large group of Trapdoor Spiders sometimes known as Funnel-web Tarantulas. The are found on every continent, though they are more common on the continents of the Southern Hemisphere, and have a fossil record that dates back to the Cretaceous.

In a paper published in the journal ZooKeys on 3 June 2019, Jason Bond of the Department of Entomology & Nematology at the University of California Davis, and Trip Lamb of the Department of Biology at East Carolina University describe a new species of Funnel-web Tarantula from Namibia.

The new species is placed in the genus Pionothele, which has previously only been recorded in South Africa, and given the specific name gobabeb, in reference to the area where it was found, close to the Gobabeb Research & Training Center, about 120 km southeast of the Atlantic coastal city of Walvis Bay, where the ephemeral drainage of the Kuiseb River meets the northern terminus of the Namib Sand Sea and the gravel plains of the Central Namib. The species is described from fifteen male specimens collected from pit traps after a rain event (this is fairly typical for Trapdoor Spiders, with the males roaming in search of females, either at certain times of year or after certain weather events), plus one female collected from a burrow on a sandy slope.

Aerial photograph of type locality. Kuiseb River bed in foreground (tree line); the interdune pitfall trap transect lies beyond the dunes (middle right of image). Bond & Lamb (2019).

The males range from 6.18 to 7.59 cm in length and from 5.72 to 6.8 cm in width, the female is 8.13 cm long and 6.08 cm wide, and notably more robust. Both sexes are pale brown in colour with fine white hairs on the body and darker hairs on the limbs. The posterior lateral eyes are much reduced in size compared to the median eyes, something not seen in the other two species in the genus.

Pionothele gobabeb, specimens in dorsal view, (3) male, and (4) female. Bond & Lamb (2019).

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Ceratogyrus attonitifer: A new species of Horned Baboon Spider from Angola.

Baboon Spiders, Harpactirinae, are large Mygalomorph Spiders (Tarantulas) found in Africa. They inhabit silk-lined burrows on the ground, from which they ambush prey, and which they will defend aggresively against any percieved threat with a painful venemous bite; this bite is reputed to be so painful that even Baboons will leave these Spiders alone. Members of the genus Ceratogyrus are widespread in Southern Africa, and are given the popular name Horned Baboon Spiders due to a large foveal horn found on the sternum of some species.

In a paper published in the jouranl African Invertebrates on 6 February 2019, John Midgley of the National Geographic Okavango Wilderness Project of the Wild Bird Trust, the Department of NaturalSciences at the KwaZulu-Natal Museum, and the Southern African Forensic Entomology Research Laboratory at Rhodes University, and Ian Engelbrecht of the South African National Biodiversity Institute and the Department of Zoology and Entomology at the University of Pretoria, describe a new species of Ceratogyrus from the Okavango catchment of Angola.

The Okavango wetland system is best known from Botswana, where it has been a major tourist attraction for decades, as well as being home to numerous scientific studies and television documentaries, but the system actually falls across three counries, Botswana, Namibia and Angola, with the majority in Angola. This Angolan part of the Okavango has recieved relatively little outside attention due ro a civil war that statrted shortly after the collapse of the Portuguese colonial empire in 1974, and lasted into the twenty first century. The National Geographic Okavango Wilderness Project has been working in the area since 2015, and aims to study the entire ecosystem across the three nations of the Okavango, and promote conservation in the area.

The new species is named Ceratogyrus attonitifer, which means 'bearer of astonishment' in reference to the surprise invoked by the discovery of this Spider. The species is described from six female specimens, collected from an undisclosed location within Moxico Province, Angola, during a National Geographic Okavango Wilderness Project in 2016. These are 20.8-40.5 mm in length and golden brown in colour, with the foveal horn much larger than seen in any previously seen member of the genus Ceratogyrus, and soft rather than rigid in nature.

Ceratogyrus attonitifer. (A) Retrolateral view, (B) dorsal view, (C) ventral view. Scale bars are 10 mm. Midgley & Engelbrecht (2019).

Ceratogyrus attonitifer is found in burrows in sandy soil in open Miombo woodland in southeastern Angola. These burrows are near vertical and about 40 cm deep, with a horizonal section at the base. The burrow has a silk colar with local materials such as twigs or grass incorporated. Any object inserted into the burrow was attacked enthusiastically. The Spiders principally feed on Insects, though local people report that the bites can be  serious, and even potenrially fatal if medical help is not available.

Habitat, burrow and live habitus of Ceratogyrus attonitifer in south-eastern Angola. (A) Aerial view of habitat at the type locality showing a dambo (wetland) amongst Miombo (Brachystegia) woodland. The expedition campsite is to the right of the dambo. Specimens were collected primarily along the margins of the wetland area. (B) Live habitus, dorsal, showing full size of the foveal protuberance in life. (C) Specimen in defensive posture typical for Baboon Spiders; background is white sand at the type locality. (D) Burrow entrance amongst grass tussocks; entrance approximately 2 cm wide. Midgley & Engelbrecht (2019).

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Dolichothele mottai & Dolichothele camargorum: Two new species of Tarantula from Brazil and Bolivia.

Tarantulas, Theraphosidae, are large and usually hairy Mygalomorph Spiders, the group that also includes Trapdoor and Baboon Spiders, and which is noted for features such as non-oposable fangs and only having two pairs of book-lungs. Most Tarantula species are found in the Americas, and while members of this group are found on every continent, most Old World species referred to as 'Tarantulas' are in fact large members of other groups, usually other Mygalomorphs or Wolf Spiders. Tarantulas seldom bite defensively, instead defending themselves with a dense covering of irritating 'urticating hairs' on their abdomens, which can be loosed by brushing with the hind legs and wafted at potential predators, causing irritation to the eyes and nose.

In a paper published in the journal ZooKeys on 21 December 2017, Irene Soliz Revollo of the Instituto de Biociências at the Universidade Estadual Paulista Júlio de Mesquita Filho, and the Laboratório de Ecologia e Evolução at the Instituto Butantan, Pedro Ismael da Silva Júnior of the Laboratório Especial de Toxinologia Aplicada, also at the Instituto Butantan, and Rogério Bertani, again of the Laboratório de Ecologia e Evolução at the Instituto Butantan, describe two new species of Tarantula from Brazil, both of which are placed in the ground-dwelling genus Dolichothele.

The first new species described is named Dolichothele mottai, in honour of the arachnologist Paulo Cesar Motta, for his work on the Mygalomorph Spiders of the Brazilian Cerrado. The species is described from two specimens, a female with a body length of 9.4 cm and a male with a body length of 8.1 cm. Both sexes are covered in iridescent red hairs. The species was found in Cerrado (savanna) environments in the Distrito Federal and state of Goiás, where they build silk tunnels under rocks and logs, males were seen roaming in search of mates in September to November.

Dolichothele mottai, male specimen. Paulo Cesar Motta in  Seliz Revollo et al. (2017).

The second new species is named Dolichothele camargorum, in honour of Erney Plessmann de Camargo and Luis Marcelo Aranha Camargo, for their work on medical and biological research in the state of Rondônia, Brazil. The species is described from two specimens, a male with a body length of 5.6 cm and a female with a body length of 10.9 cm, both are black and brown with brown hairs. The species was found in Cerrado fragments in Rondônia State in Brazil and the department of La Paz in Bolivia.

Dolichothele camargorum, female specimen. Rogério Bertani in Seliz Revollo et al. (2017).

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Aptostichus sabinae: A new species of Euctenizid Trapdoor Spider from Oaxaca State, Mexico.

Trapdoor Spiders are Mygalomorph Spiders (Spiders that lack opposable fangs, the same group as the Tarantulas) noted for the habit of excavating a burrow which they cover with a circular trapdoor, emerging from this to seize prey. They were formerly assumed to be a single taxonomic group, but the advent of molecular phylogenetic methods has revealed that several different Mygalomorph groups have independently evolved this lifestyle. The Euctenizidae are a group of about 75 Trapdoor Spiders found in the United States and Mexico. There are are currently seven genera in this family, though the majority of species, about 40, are found in a single genus, Aptostichus.

In a paper published in the journal ZooKeys on 16 December 2016, Alejandro Valdez-Mondragón of the Laboratory of Arachnology and the Colección Nacional de Arácnidos at the National Autonomous University of Mexico and Mayra Cortez-Roldán, also of the Laboratory of Arachnology
at the National Autonomous University of Mexico, describe a new species of Euctenizid Trapdoor Spider from Oaxaca State, Mexico.

The new species is placed in the genus Aptostichus and given the specific name sabinae, in honour of María Sabina Magdalena García, a famous Mazatec shaman, noted for her knowledge of healing and hallucinogenic Mushrooms, who was born in the Municipio Huautla de Jiménez, where the Spider was discovered. The species is described from a single male specimen found in the Cueva Li Nita cave, which situated at an altitude of 1919 m in a temperate forest, though it shows no adaptations to cave life, possibly living around the entrance to the cave system. The specimen is 8.3 mm in length, and is yellowish brown in colour, and covered in black hairs.

Aptostichus sabinae, male specimen in dorsal view. Scale bar is 0.5 mm. Valdez-Mondragón & Cortez-Roldán (2016).

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The origin of the Canary Islands Trapdoor Spider.

The Canary Islands are a group of volcanic islands in the northeast Atlantic, approximately 110 km off the coast of Morocco. They are true oceanic islands, never having been connected to a continent, and started to form in the Miocene about 22 million years ago, with volcanism starting on what became the island of Fuerteventura and subsequently moving to the west. The Eastern Canary Islands are now considered to be erosional in nature (i.e. the islands are now shrinking due to erosion rather than growing due to volcanism), and have an arid climate, though volcanic activity is still occasionally recorded even on Fuerteventura. The Western Canary islands are higher with volcanism being the main geological process occurring, and have a moist climate.

Like all oceanic islands the Canaries have a distinct flora and fauna, with 50% of invertebrates and 27% of vascular plants being endemic to the islands (i.e. found nowhere else). Unusually for such islands, the Canaries have their own species of Mygalomorph Spider, the Canary Islands Trapdoor Spider, Titanidiops canariensis, which is found on the East Canary Islands of Fuerteventura, Lanzarote and La Graciosa. Mygalomorph Spiders are unusual on oceanic islands, as they do not disperse easily across water. They tend to be large (the group includes Tarantulas and Baboon Spiders), ground dwelling and not prone to extensive dispersal. Several species of Tarantula are known from the Caribbean, but all belong to the genus Ummidia, the young of which are known to practice ballooning (i.e. the young Spiders let out long strings of silk which they use to catch the wind and drift to new locations, common in many Spider groups but very unusual in Mygalomorphs) and a few species are known from islands in the South Pacific.

In a paper published in the journal PLoS One on 10 December 2014, Vera Opatova and Miquel Arnedo of the Institut de Recerca de la Biodiversitat & Departamentde Biologia Animal at the Universitat de Barcelona publish the results of a genetic analysis intended to determine when the Canary Island Trapdoor Spider diverged from the related Moroccan Trapdoor Spider, Titanidiops maroccanus, and the subsequent dispersal of the Spiders within the Canaries.

Specimen of Titanidiops canariensis from Betancuria on Fuerteventura.

Opatova and Arnedo compared mutation rates in four nuclear and four mitochondrial genes in order to attempt to develop a timescale for population divergences in Titanidiops  canariensis (nuclear genes are located on the chromosomes in the cell nucleus and are subject to sexual recombination with each generation; mitochondrial genes are found in the cells mitochondria, and are always inherited from the maternal side without sexual recombination).

They found that Titanidiops canariensis probably shared a last common ancestor with species on the mainland about 12 million years ago, and that this mainland population later split into the ancestors of Titanidiops maroccanus and Idiops syriacus (a species found in Israel) about 11 million years ago. On the Canary Islands Titanidiops canariensis split into two clades (populations with a common ancestry) about 8.08 million years ago, and one of these clades again split in two about 6.98 million years ago. However, while they are confident about the relationships between the different groups, discrepancies between the nuclear and mitochondrial DNA results mean that they are not completely confident about the timings of the splits.Titanidiops maroccanus also appears to have a number of deep evolutionary splits, though this was not the main subject of the study.

This suggests that the genera Titanidiopsand Idiopsare polyphyletic, with Titanidiops maroccanus and Idiops syriacus more closely related to one-another than they are to Titanidiops canariensis, and all three species more closely related to one-another than to other members of the genus Idiops. It also suggests that there are probably at least two cryptic species of Trapdoor Spider in the Canaries classified under the name Titanidiops canariensis (cryptic species are species which appear identical, but which are nevertheless reproductively isolated; this is very common in morphologically conservative groups with low dispersal rates, such as Mygalomorph Spiders), and that Titanidiops maroccanusis also probably a cluster of cryptic species.

The genus Titanidiops appears to have only reached the Canaries on a single occasion, unsurprising given the difficulty of large Mygalomorph Spiders crossing stretches of open ocean. They note that members of the genus are found around the River Sous in Morocco, and that in the past this river is thought to have produced seasonal torrential currants as a result of a much wetter climate. This could have resulted in large rafts of vegetation being carried out to sea, some of which may have reached the Canaries. Such rafts may have carried Trapdoor Spiders, as well members of other groups which do not readily cross oceans but which are found in the Canary Islands, such as other ground Spiders, Beetles, Skinks, Geckos and Rodents.

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A Mygalomorph Spider from the Late Triassic of Italy.

Mygalomorph Spiders (Tarantulas and related species) are considered to be one of the most ancient groups of Spiders. They have two pairs of book lungs (many other Spiders have lost a pair) and downward pointing, rather than opposable fangs, again considered to be a primitive state in Spiders. Many species of Mygalomorph attain large sizes, all have flattened, disk-shaped bodies (rather than the more globular bodies of most other Spiders), and most are ambush predators.

Nine new species of tree-dwelling Tarantulas from Brazil.

Tarantulas belonging to the Subfamily Aviculariinae are tree-dwelling Tarantulas from Central and South America and the islands of the Caribbean. They are popular in the pet trade due to their docile natures; they are generally...

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A Mygalomorph Spider from the Late Triassic of Italy.

Mygalomorph Spiders (Tarantulas and related species) are considered to be one of the most ancient groups of Spiders. They have two pairs of book lungs (many other Spiders have lost a pair) and downward pointing, rather than opposable fangs, again considered to be a primitive state in Spiders. Many species of Mygalomorph attain large sizes, all have flattened, disk-shaped bodies (rather than the more globular bodies of most other Spiders), and most are ambush predators.

In a paper published in the June 2013 edition of the journal Acta Palaeontologica Polonica, Fabio Dalla Vecchia of the Institut Català de Paleontologia and Paul Selden of the Paleontological Institute and Department of Geology at the University of Kansas, describe a Mygalomorph Spider from the Late Triassic of northeast Italy.

The specimen is described as a new species, and given the name Friularachne rigoi, where 'Friularachne' means spider from Friuli, the region of Italy where it was found, and 'rigoi' honours the finder of the specimen, Roberto Rigo. The Spider is preserved as part and counterpart on a split slab of dolostone (magnesium rich limestone). It has a body-length of 3.48 mm, and a total leg-span of about 8 mm. The specimen is interpreted to be male, due to its enlarged chelicerae, which are used in mating by male Mygalomorph Spiders.

Friularachne rigoi. Part (A), and counterpart (B). Photographs (A1, B1) and explanatory drawings (A2, B2). 1–4, walking legs 1–4. Dalla Vecchia & Selden (2013).

Friularachne rigoi is tentatively assigned to the Atypoidea, Purseweb Spiders and Folding Trapdoor Spiders. If this is correct it will make Friularachne rigoi the oldest known member of the group by a long way, the oldest known Atypoid Spider to date coming from the Early Cretaceous of Mongolia. However this is not an overly surprising diagnosis; Friularachne rigoi is only the fourth Triassic Spider ever discovered, and the second Triassic Mygalomorph. However Mygalomorph Spiders are thought to have diverged from other Spider early in the history of the group, and Atypoid Spiders are similarly thought to have diverged from other Mygalomorphs very early on, so that, despite the poor fossil record of Triassic Spiders, palaeontologists would have predicted that this group were around at this time.

The specimen originates from the Dolomia di Forni Formation in the Rovadia Brook valley on the north slope of the Carnian Prealps. The Dolomia di Forni Formation is a marine dolostone noted for its fossils, which include marine Arthropods and Fish, Plant fragments and terrestrial vertebrates. Many of the Plant specimens show adaptation to a warm arid climate. It is interpreted that the terrestrial components of the Dolomia di Forni Formation assemblage were swept out to sea in flash flood events. 

Map showing the locality where the specimen was found (black Star). Dalla Vecchia & Selden (2013).

Modern Atypoid Spiders build silk-lined burrows, from which they ambush prey. The females, having dispersed from their mothers nest, build a burrow of their own, in which they remain for life, however the adult males leave their burrows in order to search for females, making them much more likely to be swept out to sea in any flash flood event.

See also Goblin Spiders from Cretaceous Amber, Nine new species of tree-dwelling Tarantulas from Brazil, Nine new species of cave-dwelling huntsman spider from Laos and New species of Cave Spider from Oregon.

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