• Cellar Spiders
• Endangered Status

This is the first comprehensive treatment of a major order of arachnids featuring more than 6,000 species worldwide, familiar in North America as daddy-longlegs but. Before addressing these awesome little nuances of harvestman biology. The Eupnoi cluster of species. One species of harvestman within. Arachnids: Harvestmen.

Contents. Position in Arachnida The relationship of harvestmen with other arachnid orders is still not sufficiently resolved. Scorpiones Opiliones Pseudoscorpiones Solifugae Dromopoda (after Giribet et al. 2002) Opiliones Scorpiones Pseudoscorpiones Solifugae Dromopoda (after Shultz 1990) Up until the 1980s they were thought to be closely related to mites. In 1990, Shultz proposed grouping them with, and ('camel spiders'); he named this. This view is currently widely accepted.

Cellar Spiders

However, the relationships of the orders within Dromopoda are not yet sufficiently resolved. When only considering recent taxa, the harvestmen appear as a sister group to (Scorpions, Pseudoscorpions, Solifugae). When also considering fossils, the harvestmen are sister to (Pseudoscorpions and Solifugae). Recent analyses have also recovered the Opiliones as sister-group to the extinct Phalangiotarbids, although this has low support. Relationship of suborders In 1796, erected the family 'Phalangida' for the then known harvestmen, but included the genus. (1892) recognized the suborders Palpatores, Laniatores, Cyphophthalmi (called Anepignathi), but also included the as a harvestman suborder.

The latter were removed from the Opiliones by Hansen and (1904), rendering the harvestmen monophyletic. Cyphophthalmi Eupnoi Dyspnoi Laniatores (after Giribet et al. 2002) Cyphophthalmi Eupnoi Dyspnoi Laniatores (after Shultz 1998) According to more recent theories, Cyphophthalmi, the most suborder, are a sister group to all other harvestmen, which are according to this system called. The Phalangida consist of three suborders, the, and. While these three are each monophyletic, it is not clear how exactly they are related. In 2002, Giribet et al.

Came to the conclusion that Dyspnoi and Laniatores are sister groups, and called them, which are sister to Eupnoi. This is in contrast to the classical hypothesis that Dyspnoi and Eupnoi form a clade called. Dyspnolaniatores was also recovered in a 2011 study. In 2014, new analysis by Garwood et al. Examined 158 morphological traits across 272 species. In Garwood's, the Opiliones split into the Phalangida and stem Cyphophthalmi.

The Cyphophthalmi stem then diversified into Cyphophthalmi proper and the newly identified, while the Phalangida split into Laniatores and the 'Palpatores'. Finally, the Palpatores diversified into Eupnoi and Dyspnoi. The analysis moves divergence of the extant suborders from the Period to the. Opiliones' own divergence is dated to 414 million years ago, which arachnid are estimated to have originated during the late to early.

Genetic analysis performed on a modern specimen found that a suppressed gene that, if active, would generate a second pair of eyes at the lateral location, providing independent evidence of four eyes being the ancestral condition. Garwood et al. Also argue that Carboniferous harvestmen diversification is more consistent with changes observed in other terrestrial, which have been linked to high oxygen levels during that period. Relationship within suborders. Phylogenetic analyses of Opiliones Cyphophthalmi The Cyphophthalmi have been divided into two infraorders, (including the superfamily, with the families, and ) and (with the superfamilies and its single family, and, including and ); however, recent studies suggest that the Sironidae, Neogoveidae and Ogoveidae are not monophyletic, while the Pettalidae and Stylocellidae are. The division into Temperophthalmi and Tropicophthalmi is not supported, with Troglosironidae and Neogoveidae probably forming a monophyletic group.

The Pettalidae are possibly the sister group to all other Cyphophthalmi. While most Cyphophthalmi are blind, eyes do occur in several groups.

Many Stylocellidae, and some Pettalidae bear eyes near or at the base of the, as opposed to most harvestmen, which have eyes located on top. The eyes of Stylocellidae could have evolved from the lateral eyes of other arachnids, which have been lost in all other harvestmen. Regardless of their origin, it is thought that eyes were lost several times in Cyphophthalmi. Spermatophores, which normally do not occur in harvestmen, but in several other arachnids, are present in some Sironidae and Stylocellidae. (Triaenonychidae) There is not yet a proposed phylogeny for the whole group of Laniatores, although some families have been researched in this regard. The Laniatores are divided into two infraorders, the ' Loman, 1900 and the Kury, 2002. However, Insidiatores is probably paraphyletic.

It consists of the two superfamilies and, with the latter closer to the Grassatores. Alternatively, the, which reside in Travunioidea, could be the sister group to all other Laniatores. The Grassatores are traditionally divided into the, and. Several of these groups are not monophyletic.

Endangered Status

Molecular analyses relying on nuclear ribosomal genes support monophyly of, (both Gonyleptoidea), (currently Assamioidea) and. The Phalangodidae and may not form a monophyletic group, thus rendering the Phalangodoidea obsolete. The families of the obsolete Assamioidea have been moved to other groups: Assamiidae and Stygnopsidae are now Gonyleptoidea, Epedanidae reside within their own superfamily, and the ' are possibly related to Phalangodidae.

References. ^ Gonzalo Giribet; Gregory D. Edgecombe; Ward C.

Wheeler; Courtney Babbitt (2002). 18 (1): 5–70. ^ Jeffrey W.

Shultz (1990). 'Evolutionary morphology and phylogeny of Arachnida'. 6 (1): 1–38.

^ Gonzalo Giribet; Adriano B. 'Phylogeny and Biogeography'. In Ricardo Pinto-da-Rocha; Glauco Machado; Gonzalo Giribet.

Garwood, Russell J.; Dunlop, Jason A. Retrieved June 15, 2015. Shultz (1998). 26 (3): 257–272.

Garwood, Russell J.; Dunlop, Jason A.; Giribet, Gonzalo; Sutton, Mark D. Nature Communications. Retrieved June 8, 2015. ^ Garwood, Russell J.; Sharma, Prashant P.; Dunlop, Jason A.; Giribet, Gonzalo.

Current Biology. 24: 1017–1023.

Retrieved April 17, 2014. External links. Biology Catalog. Department of Entomology.