Cunaxidae Thor, 1902, 1978

Skvarla, Michael J., Fisher, J. Ray & Dowling, Ashley P. G., 2014, A review of Cunaxidae (Acariformes, Trombidiformes): Histories and diagnoses of subfamilies and genera, keys to world species, and some new locality records, ZooKeys 418, pp. 1-103 : 7-10

Cunaxidae Thor, 1902

Historical review.

Linnæus (1758) described Acarus and included all mites therein. Hermann separated three mite species with elongated gnathosomas (i.e., Bdellidae and Cunaxidae ) from Acarus into Scirus . However, Hermann died in 1794 and his papers were not published until after his death by his brother-in-law F. L. Hammer in 1804 (as Hermann 1804). Latreille (1795) had by then separated the same mites into Bdella . Von Heyden (1826), recognizing that Bdella had priority over Scirus , synonomised Scirus with Bdella and erected Cyta and Cunaxa . However, many authors, including Dugés (1834a), Kramer (1881, Banks (1894), and Berlese (1904, 1910), continued to describe new species in Scirus . Dugés (1834a) erected Bdellidae ( Bdelloidea ) for Bdella and Scirus , having apparently not seen Von Heyden’s synonymization of the two genera. Trouessart (1892) moved Cunaxa from Bdellidae to Trombidiidae and erected the subfamily Scirinae . Oudemans (1902) used Cunaxinae in the same sense that Trouessart (1892) used Scirinae , that is for those mites in the family Bdellidae (sensu Dugés) that have pedipalps with a curved terminal segment and movable chela only (= Cunaxidae sensu Thor). Thor (1902) erected Cunaxidae as a family separate from Bdellidae . Oudemans (1906) disregarded Thor’s (1902) erection of Cunaxidae and kept Cunaxinae as a subfamily within Bdellidae . Van der Hammen (1972) erected the superfamily Cunaxoidea over Bdelloidea , disregarding the priority of Bdella Latreille (1795) over Cunaxa Von Heyden (1826). Den Heyer (1977b) erected Bonziinae for Bonzia and Parabonzia . Den Heyer (1978a) preserved the name Cunaxinae , but limited its concept to those cunaxids possessing 5-segmented pedipalps which extend past the subcapitulum by at least the distal two segments. Den Heyer (1978b) erected Coleoscirinae . Den Heyer (1980c) erected the monobasic Scirulinae and recognized the priority of Bdelloidea over Cunaxoidea . Bu and Li (1987a) erected Orangescirulinae . Smiley (1992) erected Denheyernaxoidinae , Neobonzinae , and Paracunaxoidinae as monotypic subfamilies and monographed and provided keys to known species. Den Heyer and Castro (2009) moved Denheyernaxoides and Paracunaxoides to Cunaxoidinae , thus disregarding Denheyernaxoidinae and Paracunaxoidinae as valid subfamilies. Lin and Zhang (2010) provided a detailed historical review of Cunaxidae in China and a checklist of species found in that country. Den Heyer (2011) moved Neobonzia to Coleoscirinae , effectively disregarding Neobonzinae , and synonymized Coleobonzia with Neobonzia .

Diagnosis.

Gnathosoma ( Figs 3-6 ). Pedipalps 3-, 4-, or 5-segmented and end in a strong claw (except in Pseudobonzia ). They may be shorter than, equal to, or extend beyond the distal end of the subcapitulum. Femora of 5-segmented pedipalps divided into basi- and telofemora, though may be secondarily fused; a dark line often indicates the previous articulation ( Fig. 5a, b illustrate a fully divided femur and Fig. 6a, b illustrate a secondarily fused femur. This is for illustration purposes only, i.e., cunaxids with long and short 5-segmented pedipalps may have either fully divided or secondarily fused femora). Telofemora and genua are uniquely fused in Allocunaxa , though the basifemoral/telofemoral articulation is present. Apophyses present or not on the telofemora, adjoining the genua and tibiotarsi, or on the tibiotarsi. Subcapitulum wedge-shaped and may be patterned with random dots or papillae, dots or papillae forming lines, a single row of cells on the posterior edge, or reticulations forming polygonal cells. Subcapitulum with up to 6 pairs of setae are present: hg1 - 4 and 2 pairs of adoral setae. Seta hg1 usually straight, but geniculate in Bonziinae and may be curved in Neoscirula ; hg4 often longest pair of subcapitular setae. Chelicerae with or without seta near the cheliceral digit.

Idiosoma, dorsal ( Fig. 7a ). Idiosoma diamond-shaped. Dorsal proterosoma covered with a sclerotized shield that bears 2 pairs of setae (lps and mps) and 2 pairs of setose sensilla (at and pt); rarely one pair of setae or sensillae absent. Dorsal hysterosoma complemented with 0-2 large shields or plates and 0-4 pairs of platelets. These plates and platelets may capture one or more pairs of setae. Up to 8 pairs of dorsal hysterosomal setae present (c1 - h1, c2, f2, and h2); h2 may occur ventrally. Setae may occur on small platelets that are barely larger than the setal socket. Integument not covered in shields, plates, or platelets is striated. Cupule im present, usually laterad and slightly posterior to e1. Dorsal idiosomal shields and plates smooth or patterned with random dots or papillae, dots or papillae forming lines, reticulations forming polygonal cells, or cells which form rows.

Idiosoma, ventral ( Fig. 7b ) Ventral idiosoma may be complemented with 1 or a few small platelets in addition to the coxae. Coxae fused to body and form plates. Coxae I-II are often fused in adults and may coalesce medially to form a sternal shield. Coxae III-IV are often fused in adults and may extend caudally beyond the genital plates. Each coxa complemented with 0-4 setae; in addition, extensive coxae or sternal shields may capture setae normally on the integument and therefore have more. Coxae may be plain or patterned with random dots or papillae, dots or papillae forming lines, or reticulations forming polygonal cells. Genital plates (sometimes called anal valves) present in adults and bear 3 (rarely) or 4 (usually) setae, except in Parabonzia which have up to 9 pairs of setae. 2 pairs of genital papillae visible underneath the plates. Anal plates (sometimes called anal valves) bear 1-2 setae (ps1-2). Setae ps2 may occur off the anal plates. Legs 6-segmented in larvae, 7-segmented in nymphs and adults. In adults these segments are coxa, trochanter, baifemur, telofemur, genu, tibia, and tarsus, however, the coxae are often treated separately from the other leg articles. Femora undivided in larvae. Trichobothrium present on leg tibia IV. Ambulacral claws present on either side of a 4-rayed empodium.

Key to Subfamilies of Cunaxidae

(modified from Smiley 1992)

1	Pedipalpal telofemoral multi-branched seta present (except Parabonzia mindanensis ) ( Fig. 7a )	Bonziinae
-	Pedipalpal telofemoral multi-branched seta absent	2
2 (1)	Pedipalps 3-segmented ( Figs 3a, b )	Cunaxoidinae
-	Pedipalps 4-segmented ( Figs 4a, b )	Scirulinae
-	Pedipalps 5-segmented (basi-and telofemora may be partially fused) ( Figs 5a, b ; 6a, b )	3
3 (2)	Pedipalps extend beyond the subcapitulum by at most the distal half of the tibiae ( Figs 5a, b )	4
-	Pedipalps extend beyond the subcapitulum by at least the distal half of the tibiae ( Figs 6a, b )	Cunaxinae
4 (3)	Trichobothrium on tibiae IV present; setae hg1 not geniculate; cheliceral seta usually present	Coleoscirinae
-	Trichobothrium on tibiae IV absent; setae hg1 geniculate; cheliceral seta absent	Orangescirulinae

Figures

Figure 7. Generalized schematic of cunaxid idiosomal morphology. 7 a Dorsal. 7 b Ventral.

Figures 3 - 6. a. dorsal. b. ventral. 3 3 - segmented pedipalp (Cunaxoidinae) 4 4 - segmented pedipalp (Scirulinae) 5 5 - segmented pedipalp that does not extend beyond the subcapitulum by more than the distal half of the genua (Bonziinae, Coleoscirinae, and Orangescirulinae) 6 5 - segmented pedipalp that reaches beyond the subcapitulum by at least the distal half of the genua (Cunaxinae).