identifier	taxonID	type	CVterm	format	language	title	description	additionalInformationURL	UsageTerms	rights	Owner	contributor	creator	bibliographicCitation
ACE9D756FA6154669DD9F1CDC4E7C863.text	ACE9D756FA6154669DD9F1CDC4E7C863.taxon	http://purl.org/dc/dcmitype/Text	http://rs.tdwg.org/ontology/voc/SPMInfoItems#GeneralDescription	text/html	en	Schizotetranychus Tragardh 1915	<html xmlns:mods="http://www.loc.gov/mods/v3">
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            <p> Genus  Schizotetranychus Trägårdh</p>
            <p>Type species.</p>
            <p> Tetranychus schizopus Zacher, 1913 . </p>
            <p>Diagnosis.</p>
            <p>Dorsal hysterosoma with ten pairs of setae (c 1-3, d 1-2, e 1-2, f 1-2, and h 1), setae h 2 and h 3 present on ventral opisthosoma, empodial claw divided deeply into two claw-like structures, palp tarsus with seven structures / setae (one spinneret, two eupathidia, one solenidion, three setiform setae); dorsal hysterosoma medially usually with transverse striations, but may be longitudinal or irregular between d 1 and e 1; two sets of duplex setae on tarsus I present distally, nearly adjacent to each other.</p>
            <p> Background and taxonomic review of the genus  Schizotetranychus</p>
            <p> The genus  Schizotetranychus was erected by Trägårdh (1915) based on  Tetranychus schizopus Zacher, 1913 and distinguished from the genus  Tetranychus by having the leg empodia divided deeply into two claw-like structures. Two years later, Banks (1917) erected the genus  Stigmaeopsis and designated  St. celarius Banks its type species. Banks (1917) described the genus  Stigmaeopsis very briefly and did not provide any diagnostic characters which could separate it from the closely related genus  Schizotetranychus . Later, McGregor (1950) synonymized the monospecific genus  Stigmaeopsis with  Schizotetranychus . This synonymy was accepted and followed by Pritchard and Baker (1955), Baker and Pritchard (1960), Tuttle and Baker (1968), Gutierrez (1968), Meyer (1974, 1987), Tuttle et al. (1976), Bolland et al. (1998), and Ehara (1999). </p>
            <p> For the first time, Ehara (1999) introduced species groups in the genus  Schizotetranychus by dividing the nine  Schizotetranychus species reported from Japan into two species groups:  schizopus (six species) with transverse striations in the anterior portion of dorsocentral area on dorsal opisthosoma and  celarius (three species) with longitudinal striations in the anterior portion of dorsocentral area on dorsal opisthosoma. </p>
            <p> Later, Saito et al. (2004) reinstated the genus  Stigmaeopsis and distinguished it from  Schizotetranychus and other genera of  Tetranychidae by having six setae / structures on the palp tarsus in the female (instead of seven); dorsal striations between c 1 and d 1, clearly longitudinal, forming a trapezoidal shape instead of having mostly transverse or longitudinal irregular without forming a trapezoidal shape in  Schizotetranychus . Also, the bases of setae e 1, d 1, and c 1 gradually become further apart than the bases of f 1 setae; if hypothetical lines connecting their bases are drawn, they form a V-shaped pattern vs these lines being almost parallel in  Schizotetranychus and related genera, as described by Saito et al. (2004). Based on these characteristics, Flechtmann (2012) transferred two  Schizotetranychus species ,  S. malkovskii Wainstein, 1956 and  S. meghalensis (Gupta &amp; Gupta, 1994) to  Stigmaeopsis . Although  S. meghalensis has transverse striations between setae c 1, d 1, and e 1, and does not satisfy several characters of  Stigmaeopsis , despite the fact that Saito et al. (2016, 2018, 2019) provisionally included this species in  Stigmaeopsis because of its six setae / structures on the palp tarsus. </p>
            <p> Morphological diagnostic features previously used for grouping  Schizotetranychus species</p>
            <p> Flechtmann (2012) categorized world 106  Schizotetranychus species into 17 groups based on following female morphological characters: body length: width ratio, dorsal setal length, shape of peritremes, number of tactile setae on tibia I. As a result, numerous species groups in the genus  Schizotetranychus based on variable morphological characters are causing confusion and misunderstanding in species identification. </p>
            <p> Peritremes distally are variously developed in  Schizotetranychus species , straight in most species, and either making a U-shape, ring, or looped distally others. Peritremes distally are anastomosing in two species  S. cajani Gupta, 1996 ,  S. prosopis Tuttle, Baker &amp; Abbatiello, 1976 . Flechtmann (2012) used this character to arbitrarily propose different groups for  Schizotetranychus species. We consider the shape of the peritreme at species level a misleading character because it is variously developed distally even in different specimens of the same species, and described and illustrated differently for one species by various authors. Also, this character was already causing confusion while attempting to separate the species groups of  Schizotetranychus created by Flechtmann (2012). </p>
            <p> Mite body shape is either oval (longer than wide in most of species), or orbicular (as long as wide in few species), or elongate (more than 2 × longer than width of body in few species). This character was used by Flechtmann (2012) to develop groups in  Schizotetranychus . However, it caused confusion in the identification of those groups because some species lie on the borderline in length and width ratios. Also, the length and width ratios could be affected by the mounting of specimens on glass slides. </p>
            <p> Dorsal and ventral idiosoma is entirely striated in almost all  Schizotetranychus species , either widely or closely spaced, except  S. reticulatus Baker &amp; Pritchard, 1960 with reticulations on the propodosoma medially, and the hysterosoma is entirely striated and rugose. The dorsal hysterosoma between setae c 1, d 1, e 1, and f 1 with transverse striations entirely in all  Schizotetranychus species except six, namely  S. hidayahae Yusof &amp; Zhang, 2003 ,  S. baltazarae Rimando, 1962 ,  S. spiculus Baker &amp; Pritchard, 1960 ,  S. brevisetosus Ehara, 1989 ,  S. rhodanus Baker &amp; Pritchard, 1960 , and  S. colocasiae Ehara, 1988 (as in Ehara &amp; Tho, 1988), in which the striations between setae e 1 and d 1 form a V-shaped pattern or is irregular. </p>
            <p> Dorsal body setae are usually setiform in  Schizotetranychus species. However, few species have awl-shaped dorsal setae with slightly expanded bases. Flechtmann (2012) used this character to develop species groups in  Schizotetranychus . However, dorsal setae were not properly illustrated or described in detail for many  Schizotetranychus species , so for those species it is very difficult to discern the exact shape (awl or setiform) of the dorsal setae. This character can be considered as supporting species level character. </p>
            <p> Taxonomic notes about two  Schizotetranychus species having six setae / structures on the palp tarsus as in the genus  Stigmaeopsis</p>
            <p> As mentioned earlier, the genus  Stigmaeopsis differs from  Schizotetranychus by having six setae / structures on the palp tarsus in females instead of seven; dorsal striations lie between c 1 and d 1 are clearly longitudinal and forming a trapezoidal shape instead of being mostly transverse or irregularly longitudinal between setae d 1 and e 1 in six  Schizotetranychus species , namely,  S. hidayahae ,  S. baltazarae ,  S. spiculus ,  S. brevisetosus ,  S. rhodanus and  S. colocasiae without forming a trapezoidal shape. Also, the bases of setae e 1, d 1, and c 1 gradually widen further apart than the bases of f 1 setae if hypothetical lines connecting their bases are drawn. They form a V-shaped pattern vs almost parallel lines are in  Schizotetranychus and related genera, as described by Saito et al. (2004). </p>
            <p> In the present study, it was found that two  Schizotetranychus species ,  S. gausus Baker &amp; Pritchard, 1960 and  S. luculentus (Tseng, 1990) have six setae / structures including spinneret and solenidion on palp tarsus. The original description of these species lacking information of palp setae. So, relying on the original illustrations, these two  Schizotetranychus species having six setae on palp tarsus are provisionally transferred to  Stigmaeopsis . Also, dorsum is entirely reticulated in  S. luculentus (Tseng, 1990) . However, dorsum with transverse striations between setae c 1, d 1 and irregular longitudinal between setae e 1 and d 1 in  S. gausus . Moreover, 16 known species of  Stigmaeopsis have five tactile setae on tibia II except  S. gausus having seven setae on tibia II. </p>
            <p> Furthermore, bases of length dorsal setae c 1, d 1 which is ~ 2 × more widely spaced to the bases of e 1 and f 1 (bases of c 1, d 1, e 1, f 1 forming a V-shaped pattern) in S. Attiah, 1967 as in all known 16  Stigmaeopsis species. Few other  Schizotetranychus species have a similar pattern of dorsal setal bases. So, the supporting diagnostic character that hypothetical lines connecting the bases of setae c 1, d 1, e 1, and f 1 forming a V-shaped taken by Saito et al. (2004) for  Stigmaeopsis while reinstating this genus to separate it from  Schizotetranychus becomes impractical. </p>
            <p> Hence it is understood from the above discussion that genus  Stigmaeopsis is different from  Schizotetranychus by only one character, the presence of six setae / structures on palp tarsus vs seven in  Schizotetranychus . All other supporting characters (longitudinal striations between setae c 1 and d 1, bases of setae c 1, d 1, e 1, and f 1 forming a V-shaped pattern) of  Stigmaeopsis taken by Saito et al. (2004, 2018) as a generic character could be considered as species level characters. </p>
            <p> Species groups and subgroups of  Schizotetranychus developed in the current study </p>
            <p> In the present research, after comprehensive taxonomic assessment of descriptions and illustrations of all known (116) species of the genus  Schizotetranychus , species grouping in this genus is reconsidered based on females using only the number of tactile setae on tibia II and species subgroups based on only the number of tactile setae on tibia I. The number of tactile setae on tibia II is found to be a consistent diagnostic character in  Schizotetranychus species and described in 110  Schizotetranychus species , even those which were very briefly described. Flechtmann (2012) used tactile setae on tibia I to separate some  Schizotetranychus groups. Pritchard and Baker (1955) and Mushtaq et al. (2021) also used tactile setae on tibia I to develop species groups in the genus  Oligonychus . Based on tibial setal counts, species groups of  Schizotetranychus can easily be recognized. </p>
            <p> In the present study, the genus  Schizotetranychus can be divided into five species groups based on the number of tactile setae on tibia II in the female:  schizopus group (52 spp.) with five setae,  asparagi group with seven setae (20 spp.),  bambusae group with eight setae (22 spp.),  spireafolia group with six setae (10 spp.) and  vermiculatus group with four setae on tibia II (four spp.). Also, keys to the world  Schizotetranychus species , species groups, and subgroups are developed for the first time. Eight  Schizotetranychus species were not assigned any species group because these have been described and illustrated very briefly without information on the number of setae on tibia I and II. </p>
            <p> 1. Species group  schizopus</p>
            <p>Diagnosis. Female: Tibia II with five setae (52 species).</p>
            <p> Exemplar species.  Schizotetranychus schizopus (Zacher, 1913)</p>
            <p> Species group  schizopus is further divided into three species subgroups based on number of tactile setae excluding solenidion on tibia I. </p>
            <p> i) Species subgroup  schizopus</p>
            <p>Diagnosis. Female. Tibia I with eight / nine setae (21 species).</p>
            <p> Exemplar species.  Schizotetranychus schizopus</p>
            <p> ii) Species subgroup  andropogoni</p>
            <p>Diagnosis. Female. Tibia I with seven setae (26 species).</p>
            <p> Exemplar species.  Schizotetranychus andropogoni (Hirst, 1926)</p>
            <p> iii) Species subgroup  taquarae</p>
            <p>Diagnosis. Female. Tibia I with six setae (5 species).</p>
            <p> Exemplar species.  Schizotetranychus taquarae Paschoal, 1971</p>
            <p> 2. Species group  asparagi</p>
            <p>Diagnosis. Female. Tibia II with seven setae (20 spp.)</p>
            <p> Exemplar species.  Schizotetranychus asparagi (Oudemans, 1928)</p>
            <p> 3. Species group  bambusae</p>
            <p>Diagnosis. Female. Tibia II with eight setae (22 spp.).</p>
            <p> Exemplar species.  Schizotetranychus bambusae Reck, 1941</p>
            <p> 4. Species group  spireafolia</p>
            <p>Diagnosis. Female. Tibia II with six setae (10 spp.).</p>
            <p> Exemplar species.  Schizotetranychus spireafolia Garman, 1940</p>
            <p> 5. Species group  vermiculatus</p>
            <p>Diagnosis. Female. Tibia II with four setae (04 spp.).</p>
            <p> Exemplar species.  Schizotetranychus vermiculatus Ehara &amp; Wongsiri, 1975</p>
            <p>Ungrouped species</p>
            <p> The following eight species were not assigned any species group because these have been described and illustrated very briefly without information of number of tactile setae on tibiae I and II.  Schizotetranychus setariae Meyer, 1987 was not assigned to any species group / subgroup because it was only described / known from the male. </p>
            <p> S. graminicola Goux, 1949</p>
            <p> S. glabrisetus (Ugarov &amp; Nikolskii, 1937)</p>
            <p> S. tuberculatus (Ugarov &amp; Nikolski, 1937)</p>
            <p> S. guatemalae-novae (Stoll, 1886)</p>
            <p> S. hindustanicus (Hirst, 1924)</p>
            <p> S. mustafaii Mustafa &amp; Chaudri, 1972 (as in Mustafa et al. 1972) </p>
            <p> S. oudemansi Reck, 1948</p>
            <p> S. setariae Meyer, 1987</p>
            <p> Moreover, two  Schizotetranychus species ,  S. gausus and  S. luculentus , that have six setae / structures including spinneret and a solenidion on the palp tarsus based on original illustrations, are provisionally transferred to  Stigmaeopsis . Further studies are required to confirm the clear taxonomic status of these two species. </p>
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	https://treatment.plazi.org/id/ACE9D756FA6154669DD9F1CDC4E7C863	Public Domain	No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.		Pensoft via Plazi	Kamran, Muhammad;Hafeez, Abdul;Alatawi, Fahad Jaber;Flechtmann, Carlos Holger Wenzel	Kamran, Muhammad, Hafeez, Abdul, Alatawi, Fahad Jaber, Flechtmann, Carlos Holger Wenzel (2024): Species groups, subgroups, and key to world species of the genus Schizotetranychus Trägårdh, 1915 (Acari, Prostigmata, Tetranychidae). ZooKeys 1211: 131-150, DOI: 10.3897/zookeys.1211.127353
