Polystoechotites

Theodore Dru Alison Cockerell named the first species in 1908 as Polystoechotes piperatus, placing the fossil species into the living western hemisphere genus Polystoechotes, which is found in montane regions of North and South America. When Frank Carpenter re-examined the fossil in the early 1940s he concluded, based on the breadth of the costal region that the fossil was likely an osmylid lacewing and transferred the species to the extinct genus Propsychopsis as Propsychopsis piperatus. This placement was retained by Ellis MacLeod (1970) who reviewed and updated the Baltic Amber psychopsids. Generic placement of the species was again questioned in 2003, when Vladimr Makarkin & S. Bruce Archibald reviewed the fossil record of Polystoechotidae in conjunction with placement of the lacewing genus Palaeopsychops into the family and description of a new species. Three years later, Archibald and Makarkin (2006) described a larger polystechotid fauna from the Eocene Okanagan Highlands, detailing seven named species and two unnamed species. Three of the species named, plus the two described but unnamed species were placed into a "parataxon" named Polystoechotites. Taxa placed within the parataxon were all considered by Archibald and Makarkin to belong to the family Polystoechotidae, the "giant lacewings", but due to preservation quality or incompleteness of the fossil, could not be placed into an already described genus, or confidently be given a new genus. Each was considered identifiable as a species based on both the vein structure of the wings, using the Comstock–Needham system, and the preserved color patterning. As a form taxon, the parataxon Polystoechotites was not given a formal taxonomic description, and Archibald and Makarkin acknowledged it would contain an artificial grouping of species, rather than true monophyletic clade. At the time of naming, Polystoechotites Polystoechotidae was treated by entomologists as a separate family of lacewings. however in 2010 the family Polystoechotidae was merged into the "moth lacewing" family Ithonidae, with the polystoechotids treated as an internal clade based on molecular phylogenic analysis. ==Description==

As a parataxon, the Polystoechotites parataxon was not given a specific description, however each of the referred species were given unique descriptions, pending more complete specimens being found. However, by the time Archibald and Makarkin were preparing to study fossils for their 2006 paper, the specimen had been lost, and thus the descriptive work for the species diagnosis was accomplished based on examination of existing photographs. Due to Q-0421 going missing, Archibald and Makarkin decided that they could not formally name the taxon, and instead used the informal name Polystoechotites "Sp. A". Specimen Q-0379 is very fragmentary, with only of the wing present, while Q-0421 was a complete wing long by wide. The wing has one preserved nygma, present in the expanded region between the Rs1 and Rs2 veins, and trichosors are preserved along the apical margin of the wing at least. The color-patterning consists of thin alternating dark and light stripes running across the wing membrane from the leading edge to the hind edge where the bands change to rounded patches straddling the wing margin. The costal space is narrow at the base before widening for the quarter of its length between base and apical area. It widens again notably after the possibly fusion point of the R1 and Sc veins near the wing tip. A well developed outer gradate series of crossveins is present, and numerous additional cross veins are scattered in the radial space. The Rs vein has approximately 23 branches, and the R1 has five preserved crossveins. Unlike other species placed in Polystoechotites, there are no preserved crossveins in the subcostal area. Polystoechotites "Sp. B" Polystoechotites "Sp. B" is known from a single poorly fossilized specimen found at Quilchena that consists of a partial pair of overlaid fore-wings. The fragments are long and only wide as preserved, and as such Archibald and Makarkin estimated the wings in life to have been approximately long. The wings have a uniform dark coloration similar to P. barksdalae, however it differs in the wider width of the costal space and the likely presence of a costal gradate series of crossveins. While there are only a few scattered costal space crossveins in P. barksdalae, in the proximal costal area at least eleven were seen on one "Sp. B" wing and seven on the other. The section of Rs that is preserved shows only one fork, and only a scattered placement of crossveins. Due to the poor preservation of the fossils, it wasn't possible to tell if some radial spaces areas were densely covered in trichiation, as is seen in Palaeopsychops setosus or if it was just apparent texturing of the wing area during the fossilization process. ==Distribution and paleoenvironment==

The majority of Polystoechotites fossils have been recovered from the Eocene Okanagan Highlands in Central British Columbia and northeast central Washington state, with three named species from the Klondike Mountain Formation of Washington, and a further two unnamed species from the Coldwater Beds Quilchena site. All three Okanagan Highlands sites represent upland lake systems that were surrounded by a warm temperate ecosystem with nearby volcanism. The highlands likely had a mesic upper microthermal to lower mesothermal climate, in which winter temperatures rarely dropped low enough for snow, and which were seasonably equitable. LMA of the Horsefly flora returned a mean annual temperature of . These are lower than the mean annual temperature estimates given for the coastal Puget Group, which is estimated to have been between . The bioclimatic analysis for Republic, Quilchena, and Horsefly suggest mean annual precipitation amounts of and respectively. The Florissant Formation is composed of successive lake deposits resulting from a volcanic debris flow damming a valley. When Polystoechotites piperatus was described, the Florissant Formation was considered to be Miocene in age, based on the flora and fauna preserved. Successive research and fossil descriptions moved the age older and by 1985 the formation had been reassigned to an Oligocene age. Further refinement of the formation's age using radiometric dating of sanidine crystals has resulted in an age of placing the formation in the Priabonian stage of the Late Eocene. The Florissant paleoforest surrounding the lake has been described as similar to modern southeastern North America, with a number of taxa represented that are now found in the subtropics to tropics and confined to the old world. Harry MacGinitie (1953) suggested a warm temperate climate based on the modern biogeographic relatives of the biota found in the formation. Modern estimates of the paleoelevation range between , notably higher than the original estimates by MacGinitie of . Estimates of the mean annual temperature for the Florissant Formation have been derived from climate leaf analysis multivariate program (CLAMP) analysis and modern forest equivalencies of the paleoflora. The results of the various methods have gaven a mean annual temperature rage between approximately , while the bioclimactic analysis for suggests mean annual precipitation amounts of . ==References==