Belongs within: Cheyletiellidae.
The Ornithocheyletiini are a group of cheyletid mites specialised for parasitism on birds, characterised by enlarged tarsal claws with an apical knob on the dorsum of the tarsus almost completely covering the pretarsus and claws (Bochkov & Fain 2001).
The Ornithocheyletiini: making a living off birds
Published 18 April 2020
In an earlier post, I commented on the carnivorous mites of the family Cheyletidae. These rapacious micropredators are commonly associated with the nests and burrows of terrestrial vertebrates, attacking debris-feeders drawn in by the host’s leavings. With such a close association already in place, it should come as little surprise that some lineages within the Cheyletidae have learnt to bypass scavenger predation and go directly to the source, becoming parasites of the vertebrate hosts themselves.
One such lineage is the Ornithocheyletiini, members of which are parasites of birds. Like other parasitic cheyletids, ornithocheyletiins have a relatively small, simple gnathosoma (the ‘head’ of the mite), no eyes, and lack the large, pectinate, claw-like setae found on the palps of free-living predatory cheyletids (instead, the setae at this position are small and smooth though they do still have hooked ends). Ornithocheyletiins are further distinguished from other cheyletids by having particularly large claws at the end of each leg that are overhung by a well developed knob on the end of the tarsus (Bochkov & Fain 2001).
Ornithocheyletiins live on the skin of their bird hosts. In the genera Ornithocheyletia and Bakericheyla, the mites spin a protective web beneath which they live and feed. Members of the tribe have been recorded from a number of bird orders, mostly smaller land birds (Passeriformes, Columbiformes, Piciformes, Coraciiformes, Psittaciformes and Apodiformes). At least one species of Ornithocheyletia was described from the Natal spurfowl Pternistis natalensis, a galliform. Members of the genus Apodicheles are restricted to species of Apodiformes (swifts) but other genera are found on a wider range of hosts. One cosmopolitan species, Bakericheyla chanayi, has been found on hosts of both the orders Passeriformes and Coraciiformes. The exact method of exploiting their host may vary: species of Bakericheyla feed on blood whereas Ornithocheyletia species feed on lymph fluid.
Historically, parasitic cheyletids were treated as a separate family Cheyletiellidae but are now classified with their free-living relatives. The exact relationships between free-living and parasitic cheyletids remain open to question. A morphological phylogenetic analysis of cheyletids by Bochkov & Fain (2001) did recover the parasitic forms as a clade but this result was questioned by the authors themselves. Instead, they suggested that the various parasitic tribes of Cheyletidae represented independent lineages whose shared features represented convergent adaptations to the parasitic lifestyle. The Ornithocheyletiini might, for instance, be compared to tribes such as the Cheletosomatini that inhabit the quills of bird feathers but feed on other quill-inhabiting mites rather than the birds themselves. Did ornithocheyletiins evolve from using birds as hunting grounds to using birds as food, or did they carry their parasitic habits with them from some other host?
Systematics of Ornithocheyletiini
Characters (from Bochkov & Fain 2001): Gnathosoma less than 30% of idiosomal length, without protrusions. Gnathosomal apex with short median protuberances. Palpal tarsi with 4-3 short nude setae. Palpal claws curved ventrolaterally, without teeth, not thickened. All setae of palpal tibia hair-like. Palpal femur with three setae, palpal genu with two setae not fused with femur, without protrusions or with small protrusions. Idiosoma ovate. Eyes absent. Shoulder-like projections of idiosoma absent. All idiosomal setae, excluding 15, not exceeding half of idiosomal length. Neotrichial setae absent. Length of all legs not exceeding idiosomal length. Legs IV normally developed. Tarsi thickened with knobs covering pretarsus. Guard seta of tarsus I hair-like, solenidion ω1 situated in apical half of tarsus I. Tibia I with solenidion. Tibia II without solenidion. Genu I with rod-like solenidion or globular. Seta v1 of tarsus I situated at same level as solenidion ω1 and guard seta. Pretarsus and well-developed claws present on all legs. Apical seta of tarsus I normally long. Tarsal setae p’ and p” hair-like, but sometimes deeply dissected or feather-like. Coxae III with 2-1 setae. Trochanters III-IV with or without seta. Distance between coxae II and III less than half of the idiosomal width.
<==Ornithocheyletiini [Ornithocheyletiinae]
| i. s.: Ornithocheyla Lawrence 1959S77
| `--*O. megaphallos Lawrence 1959S77
|--+--Bakericheyla Volgin 1966BF01
| | |--*B. chanayi (Berlese & Trouessart 1889)S77 [=Cheyletiella chanayiH98, Neocheyletiella chanayiH98]
| | | |--B. c. chanayiBF01
| | | `--B. c. latiorBF01
| | |--B. africanaBF01
| | |--B. benoitiBF01
| | |--B. fainiBF01
| | |--B. subquadrataBF01
| | `--B. transvaalicaBF01
| `--+--Apodicheles Fain 1976 [Apodichelini]BF01
| `--Neocheyletiella Baker 1949 [Neocheyletiellini]BF01
| |--*N. rohweri Baker 1949B49
| |--N. aegithali Bochkov & OConnor 2003MB14
| |--N. amandavae Fain 1972MB14
| |--N. ardeola Bochkov & Ochoa 2005MB14
| |--N. artami Domrow 1966H98
| |--N. avicola Fain 1972MB14
| |--N. athene Fain & Bochkov 2002MB14
| |--N. canadensis (Banks 1909) [=Cheyletiella canadensis]B49
| |--N. heteropalpus (Megnin 1878) (see below for synonymy)B49
| |--N. lonchurae Fain & Bochkov 2002MB14
| |--N. macronycha (Megnin 1878) [=Cheyletus macronycha, Cheletiella macronycha]B49
| |--N. media Fain 1972 [incl. N. alfortensis Guilhon & Euzeby 1984]MB14
| |--N. megaphallos (Lawrence 1959)MB14
| |--N. microrhyncha (Berlese & Trouessart 1889) [=Cheyletiella microrhyncha, Cheletiella microrhyncha]B49
| |--N. nectarinia Bochkov & OConnor 2003MB14
| |--N. oudemansi Volgin 1969 [incl. N. callawayae Smiley 1970]S77
| |--N. parvisetosa Mertins & Bochkov 2014MB14
| |--N. pinguis (Berlese 1889) [=Cheyletiella pinguis, Cheletiella pinguis]B49
| |--N. pittae Fain 1972MB14
| |--N. queleae Fain & Bochkov 2002MB14
| |--N. siva Fain 1972MB14
| |--N. smallwoodae Baker 1949B49
| `--N. vestergaardi Smiley 1977S77
`--Ornithocheyletia Volgin 1964BF01
|--*O. dubinini Volgin 1964S77
|--O. aitkeniBF01
|--O. argentinensisBF01
|--O. barri Smiley 1977S77
|--O. canadensisBF01
|--O. eulabesBF01
|--O. francoliniBF01
|--O. garrulaxBF01
|--O. geopeliaeBF01
|--O. gersoniS77
|--O. granatinaBF01
|--O. hallaeBF01
| |--O. h. hallaeBF01
| `--O. h. similisBF01
|--O. lamprocoliusBF01
|--O. lawrenceae Smiley 1970H98
|--O. lepidusBF01
|--O. leiothrixBF01
|--O. lichmerae Smiley 1984 [=Orinthocheyletia (l. c.) lichmerae]H98
|--O. lonchurae Smiley 1984H98
|--O. lukoschusiBF01
|--O. mironoviBF01
|--O. phylloscopiBF01
|--O. pinguisBF01
|--O. psittaciBF01
| |--O. p. psittaciBF01
| `--O. p. poicephaliBF01
|--O. psittaculaeBF01
|--O. smileyiBF01
`--O. volginiS77
Neocheyletiella heteropalpus (Megnin 1878) [=Cheyletus heteropalpus, Cheletiella heteropalpa, Cheyletiella heteropalpus]B49
*Type species of generic name indicated
References
[B49] Baker, E. W. 1949. A review of the mites of the family Cheyletidae in the United States National Museum. Proceedings of the United States National Museum 99 (3238): 267–320.
[BF01] Bochkov, A. V., & A. Fain. 2001. Phylogeny and system of the Cheyletidae (Acari: Prostigmata) with special reference to their host-parasite associations. Bulletin de l’Institut Royal des Sciences Naturelles de Belgique Entomologie 71: 5–36.
[H98] Halliday, R. B. 1998. Mites of Australia: A checklist and bibliography. CSIRO Publishing: Collingwood.
[MB14] Mertins, J. W., & A. V. Bochkov. 2014. Key to species of the genus Neocheyletiella (Acariformes: Cheyletidae), with description of a new species. Journal of Medical Entomology 51 (6): 1116–1121.
[S77] Smiley, R. L. 1977. Further studies on the family Cheyletiellidae (Acarina). Acarologia 19 (2): 225–241.