Atropacarus

Atropacarus sp., copyright Scott Justis.

Belongs within: Phthiracaridae.

Atropacarus is a cosmopolitan genus of phthiracarid mites with three or four pairs of closely-placed setae on the inner margin of the ano-adanal plates.

On Atropacarus
Published 18 October 2020

Atropacarus is a genus of the Phthiracaroidea, a group of box mites characterised by the plates on the underside of body being relatively wide, in contrast to the narrow ventral plates of its sister group, the Euphthiracaroidea. The difference in configuration of these plates reflects a difference in the way that the body is contracted to allow legs and prosoma to be withdrawn beneath the protective cover of the notogaster. In euphthiracaroids, the sides of the notogaster are contracted inwards; in phthiracaroids, the ventral plates of the body are lifted upwards (Schmelzle et al. 2015).

The classification of phthiracaroids is subject to conflict with two main systems in the recent literature. In one, championed by the Polish acarologist Wojciech Niedbała, the phthiracaroids are divided between two families with Atropacarus in the Steganacaridae. Species of Atropacarus have the surface of the notogaster extensively covered with dimples. The dorsal seta on the tibia of the fourth leg is short and closely associated with a solenidion (a type of specialised sensory hair). The setae of the genital plate are arranged in a more or less straight row along the inner margin of the plate with the fifth and sixth setae further apart than the fourth and fifth (Niedbała 1986c). Niedbała divides Atropacarus between two subgenera. In Atropacarus sensu stricto, there are sixteen or more pairs of setae on the notogaster and the second adanal seta is moved inwards on the ano-adanal plate to form a more or less straight line with the anal setae. In Hoplophorella, there are fifteen pairs of setae on the notogaster and the second adanal seta is distinctly laterally placed relative to the anal setae.

The super-hairy Atropacarus niedbalai, from Liu & Zhang (2013). Scale bar = 100 µm.

In the competing system, used for instance by Subías (2019), Atropacarus and Hoplophorella are treated as distinct genera and each is in turn divided into subgenera by the number of setae on the ano-adanal plate. Atropacarus sensu stricto has four pairs of such setae whereas Hoplophorella has three. Within ‘Hoplophorella’, members of the subgenus Kakophthiracarus are characterised by having all setae in the anogenital region very short and fine.

To a certain extent, of course, the question of whether to treat Atropacarus and Hoplophorella as genera or subgenera is arbitrary. Nevertheless, this arguably cosmetic distinction does relate to an underlying difference in theory. The classification of phthiracaroids used by Subías (2019) is a largely diagnostic one, inspired by a desire to facilitate specimen identifications. Niedbała’s classification, in contrast, is intended to reflect phylogenetic relationships. Simple setal counts may be convenient when composing keys but one might question its overall phylogenetic significance. Neotrichy (increases in setal count by multiplication of the original setae) is not uncommon in phthiracaroids, particularly on the notogaster. Setal counts may vary between individuals of a single species and overall neotrichy reaches an extreme in the New Zealand species Atropacarus niedbalai. In this species, the basic count of fifteen or sixteen pairs of notogastral setae has been increased to 109 or 115 pairs, with further neotrichy on the prodorsum and ventral plates (Liu & Zhang 2013). Subías (2019) defends his choice of classification by arguing that Niedbała’s key features are often difficult to discern. I sympathise with the difficulty but, as a wise man once said, species are under no obligation to evolve with regard to the convenience of taxonomists.

Systematics of Atropacarus
<==Atropacarus Ewing 1917 [incl. Helvetacarus Mahunka 1993]S04
    |--A. (Atropacarus)N07
    |    |--*A. (A.) striculus (Koch 1841)S04, N06 [=Hoplophora striculaS04, Hoploderma striculumM98, Steganacarus striculusG34]
    |    |    |--A. s. striculus [incl. Steganacarus diaphanus Jacot 1930, S. senex Aoki 1958, S. trichosus Mahunka 1982]S04
    |    |    `--A. s. insularis (Weigmann 1976) [=Steganacarus insularis]S04
    |    |--A. (A.) absimilis (Niedbała 1982) [=Steganacarus (A.) absimilis]S04
    |    |--A. (A.) clavatus Aoki 1980N86a [=A. striculus clavatusA80]
    |    |--A. (A.) clavigerus (Berlese 1904)N84 (see below for synonymy)
    |    |--A. (A.) csiszarae (Balogh & Mahunka 1979) [=Steganacarus csiszarae]N86a
    |    |--A. (A.) decipiens (Niedbała 1984) [=Steganacarus (A.) decipiens]S04
    |    |--A. (A.) echinodiscus (Mahunka 1982) [=Steganacarus echinodiscus]N86a
    |    |--A. (A.) folious Niedbała 2003N07
    |    |--A. (A.) griseus (Niedbała 1984) [=Steganacarus (A.) griseus]S04
    |    |--A. (A.) immundus (Niedbała 1983) [=Steganacarus (A.) immundus]S04
    |    |--A. (A.) inculpatus (Niedbała 1984) [=Steganacarus (A.) inculpatus]S04
    |    |--A. (A.) maculosus (Niedbała 1983) [=Steganacarus (A.) maculosus]S04
    |    |--A. (A.) mirabilis (Mahunka 1979) [=Steganacarus mirabilis]N86a
    |    |--A. (A.) murciensis Niedbała 1986N86b
    |    |--A. (A.) obesus (Niedbała 1983) [=Steganacarus (A.) obesus]S04
    |    |--A. (A.) ochraceus (Niedbała 1983) [=Steganacarus (A.) ochraceus]S04
    |    |--A. (A.) parvulus (Niedbała 1983) [=Steganacarus (A.) parvulus]S04
    |    |--A. (A.) perversus (Niedbała 1983) [=Steganacarus (A.) perversus]S04
    |    |--A. (A.) phyllophorus (Berlese 1904)N86a (see below for synonymy)
    |    |--A. (A.) platakisi (Mahunka 1979)N86a, S04 (see below for synonymy)
    |    |--A. (A.) serratus (Feider & Suciu 1957)N84, S04 [=Steganacarus serratusS04]
    |    |--A. (A.) substrictus (Niedbała 1983) [=Steganacarus (A.) substrictus]S04
    |    |--A. (A.) terrapene (Jacot 1937) [=Steganacarus terrapene]N86a
    |    `--A. (A.) wandae (Niedbała 1981)N86a [=Steganacarus wandaeS04; incl. S. navarrensis Moraza 1985S04]
    |--A. (Hoplophorella Berlese 1923)N07, S04
    |    |--A. (*H.) cucullatus (Ewing 1909)BB92, S04 (see below for synonymy)
    |    |    |--A. c. cucullatus (see below for synonymy)S04
    |    |    `--‘Hoplophorella’ c. curassensis Willmann 1936S04
    |    |--‘Hoplophorella’ (H.) angolensis Mahunka 1984S04
    |    |--‘Hoplophorella’ (H.) berninii (Niedbała 1991) [=Protophthiracarus berninii]S04
    |    |--‘Hoplophorella’ (H.) brasiliensis (Niedbała 1988) [=Austrophthiracarus brasiliensis]S04
    |    |--A. (H.) brevipilis (Balogh 1958) [=Steganacarus brevipilis]N86a
    |    |--A. (H.) buffaloensis Niedbała 2006N06
    |    |--‘Hoplophorella’ (H.) collaris (Balogh 1958) [=Steganacarus collaris]S04
    |    |--‘Hoplophorella’ (H.) craterifer (Hammer 1971)S04 [=Steganacarus crateriferS04, Notophthiracarus crateriferN86a]
    |    |--A. (H.) diaphoros Niedbała 2000S04
    |    |--‘Hoplophorella’ (H.) digna Niedbała 1983S04 [=Protophthiracarus dignusN86a]
    |    |--A. (H.) dissimilis Niedbała 1998S04
    |    |--‘Hoplophorella’ (H.) dubia (Niedbała 1992)S04 [=Hoplophthiracarus dubiusS04, Austrophthiracarus dubiusN86a]
    |    |--‘Hoplophorella’ (H.) ensifera Mahunka 1985S04
    |    |--‘Hoplophorella’ (H.) ephippigera (Balogh & Mahunka 1977) [=Steganacarus ephippiger]S04
    |    |--‘Hoplophorella’ (H.) evergladensis (Niedbała 2001) [=Protophthiracarus evergladensis]S04
    |    |--‘Hoplophorella’ (H.) fonseciai (Pérez-Íñigo & Baggio 1980)S04 (see below for synonymy)
    |    |--A. (H.) frondeus Niedbała 2003N07
    |    |--‘Hoplophorella’ (H.) grandjeani Niedbała 1981S04 [=Protophthiracarus grandjeaniN86a]
    |    |--A. (H.) hamatus (Ewing 1909)N07 (see below for synonymy)
    |    |--‘Hoplophorella’ (H.) heterotricha Mahunka 1984S04
    |    |--A. (H.) insolens (Neidbala 1988)N86a, S04 [=Hoplophorella insolensS04]
    |    |--A. (H.) kulczynskii (Niedbała 1981) [=Hoplophorella kulczynskii]N86a
    |    |--‘Hoplophorella’ (H.) lanceoseta (Balogh & Mahunka 1981)S04 (see below for synonymy)
    |    |--‘Hoplophorella’ (H.) lanceosetoides Mahunka 1985S04
    |    |--‘Hoplophorella’ (H.) lemuria Mahunka 1993S04
    |    |--‘Hoplophorella’ (H.) manipurensis Misra, Bhaduri & Raychaudhuri 1982S04
    |    |--A. (H.) minisetosus (Mahunka 1978) [=Hoplophorella minisetosa]N86a
    |    |--‘Hoploderma’ multipunctatum Sellnick 1918S93
    |    |--‘Hoplophorella’ (H.) neonominata Subías 2004 (see below for synonymy)S04
    |    |--A. (H.) nigeriensis Badejo, Woas & Beck 2001S04
    |    |--A. (H.) oblongus (Niedbała 1983) [=Hoplophorella oblonga]N86a
    |    |--A. (H.) pallens (Niedbała 1983)N91, S04 [=Hoplophorella pallensS04]
    |    |--‘Hoplophorella’ (H.) paraensis (Pérez-Íñigo & Baggio 1996) [=Protophthiracarus paraensis]S04
    |    |--A. (H.) pergratus Niedbała 1998 [=Hoplophorella pergrata]S04
    |    |--‘Hoplophorella’ (H.) perisi Subías & Sarkar 1984S04
    |    |--‘Hoplophorella’ (H.) pervicax (Niedbała 1984)S04 [=Hoplophthiracarus pervicaxS04, Austrophthiracarus pervicaxN86a]
    |    |--‘Hoplophorella’ (H.) praeoccupata Subías 2004 (see below for synonymy)S04
    |    |--‘Hoplophorella’ (H.) prominens (Balogh 1958)S04 [=Steganacarus prominensS04, Protophthiracarus promineusN86a]
    |    |--‘Hoplophorella’ (H.) pustulata Mahunka 1993S04
    |    |--A. (H.) rangiroaensis (Hammer 1972) [=Hoplophorella rangiroaensis]N86a
    |    |--‘Hoplophorella’ (H.) remigera (Berlese 1923) [=Phthiracarus (Trachyhoplophora) remiger]S04
    |    |--‘Hoplophorella’ (H.) repetita Subías 2004 (see below for synonymy)S04
    |    |--‘Hoplophorella’ (H.) sabahna Mahunka 1991S04
    |    |--‘Hoplophorella’ (H.) sculptilis (Niedbała 1988)S04 (see below for synonymy)
    |    |--A. (H.) singularis (Sellnick 1959)N91, S04 (see below for synonymy)
    |    |--A. (H.) stilifer (Hammer 1961)N91, S04 (see below for synonymy)
    |    |--‘Hoplophorella’ (H.) subciliata Mahunka 1983S04
    |    |--A. (H.) subitus (Niedbała 1983) [=Hoplophorella subita]N86a
    |    |--‘Hoplophorella’ (H.) subsellata Balogh & Mahunka 1977S04 (see below for synonymy)
    |    |--‘Hoplophorella’ (H.) tripartita (Niedbała & Schatz 1996) [=Protophthiracarus tripartitus]S04
    |    |--‘Hoplophorella’ (H.) unqus (Niedbała 1991) [=Notophthiracarus unqus]S04
    |    |--‘Hoplophorella’ (H.) varia (Niedbała & Schatz 1996) [=Protophthiracarus varius]S04
    |    |--‘Hoplophorella’ (H.) varians Jacot 1933S04
    |    |--‘Hoplophorella’ (H.) venusta Niedbała 1983S04 [=Protophthiracarus venustusN86a]
    |    `--A. (H.) vitrinus (Berlese 1913)N01, S04 (see below for synonymy)
    |--‘Hoplophorella’ (Kakophthiracarus Mahunka 1992)S04
    |    |--A. (K.) tuberculosissima (Mahunka 1978)N86a, S04 (see below for synonymy)
    |    |--‘Hoplophorella’ (K.) balazsi Mahunka 1983S04
    |    |--‘Hoplophorella’ (K.) cavernosa Mahunka 1987S04
    |    |--‘Hoplophorella’ (K.) enigmatica (Mahunka 1996) [=Kakophthiracarus enigmaticus]S04
    |    |--A. (K.) multirugosus (Mahunka 1978)N86a, S04 (see below for synonymy)
    |    |--‘Hoplophorella’ (K.) multituberculata (Balogh & Mahunka 1966)S04 (see below for synonymy)
    |    `--‘Hoplophorella’ (K.) mwali (Mahunka 1994) [=Kakophthiracarus mwali]S04
    `--‘Hoplophorella’ (Steganacarellus Mahunka 1986)S04
         |--‘Hoplophorella’ (*S.) reducta (Mahunka 1986) [=*Steganacarellus reductus]S04
         |--‘Hoplophorella’ (S.) ‘heterotricha’ (Niedbała 2000) (see below for synonymy)S04
         |--‘Hoplophorella’ (S.) paraparvula (Niedbała 2000) [=Notophthiracarus paraparvulus]S04
         `--‘Hoplophorella’ (S.) parvula (Niedbała 1998) [=Notophthiracarus parvulus]S04
Atropacarus incertae sedis:
  A. bichei Niedbała 1986S04
  A. ciliosus Niedbała 2002S04
  A. clavatus Aoki 1980 [=A. sticulus clavatus]S04
  A. controversus Niedbała 2000S04
  A. genavensis (Mahunka 1993) [=Helvetacarus genavensis]S04
  A. inconditus Mahunka 1991S04
  A. macrosculpturatus (Mahunka & Mahunka-Papp 1999) [=Steganacarus macrosculpturatus]S04
  A. multisetosus Niedbała 2002S04
  A. paraclavatus Niedbała 2002S04
  A. punctulatus Moraza 1985S04
  ‘Hoplophorella’ thoreaui (Jacot 1930)N83

Atropacarus (Atropacarus) clavigerus (Berlese 1904)N84 [=Hoploderma clavigerumN84, Steganacarus (A.) clavigerusN84; incl. Phthiracarus lutulentus Sellnick 1920S04]

Atropacarus (Atropacarus) phyllophorus (Berlese 1904)N86a [=Hoploderma phyllophorumS04, Steganacarus phyllophorusN86a; incl. S. ropalus Feider & Suciu 1957S04]

Atropacarus (Atropacarus) platakisi (Mahunka 1979)N86a, S04 [=Steganacarus platakisiS04; incl. A. papillatus Gil-Martín, Subías & Arillo 1992S04]

Atropacarus (*Hoplophorella) cucullatus (Ewing 1909)BB92, S04 [=Hoploderma cucullatumS04, Hoplophora cucullatumBB92, *Hoplophorella cucullataS04]

Atropacarus (*Hoplophorella) cucullatus cucullatus (Ewing 1909) [incl. Hoplophorella cucullata cuculloides Jacot 1933, Hoploderma licnophorum Berlese 1913]S04

Atropacarus (Hoplophorella) hamatus (Ewing 1909)N07 [=Hoploderma hamatumS04, Hoplophorella hamataS04; incl. Hoplophorella cochlearia Pérez-Íñigo & Baggio 1993S04, Hoplophorella cuneiseta Mahunka 1988S04, Hoplophorella cucullata floridae Jacot 1933S04, Atropacarus (Hoplophorella) floridaeN91, Hoplophorella glauca Hammer 1972S04, A. (H.) glaucusN07, Hoplophorella ligulifera Mahunka 1987S04, Phthiracarus (H.) cucullatus obsoletior Berlese 1923S04, Hoplophorella schauenbergi Mahunka 1978S04, Atropacarus (H.) schauenbergiN91, Hoplophorella spatulata Parry 1980S04]

Atropacarus (Hoplophorella) singularis (Sellnick 1959)N91, S04 [=Hoplophorella singularisS04; incl. Hoplophthiracarus marianus Aoki 1994N06, Hoplophorella queenslandicus Balogh & Mahunka 1978S04, Hoplophorella regalis Mahunka 1978S04, Hoplophorella sundarbanensis Sanyal & Bhaduri 1982S04]

Atropacarus (Hoplophorella) stilifer (Hammer 1961)N91, S04 [=Steganacarus stiliferS04, Hoplophorella stiliferaS04; incl. Hoplophorella benoiti Mahunka 1984S04]

Atropacarus (Hoplophorella) vitrinus (Berlese 1913)N01, S04 [=Hoploderma vitrinumS04, Hoplophorella vitrinaS04; incl. Hoplophorella africana Wallwork 1967S04, Steganacarus andrei Balogh 1958S04, Hoplophorella lienhardi Mahunka 1987S04, Hoplophorella raychaudhurii Subías & Sarkar 1984S04, Hoplophorella scapellata Aoki 1965S04, Atropacarus (Hoplophorella) scapellatusN91]

Atropacarus (Kakophthiracarus) multirugosus (Mahunka 1978)N86a, S04 [=Steganacarus multirugosusS04, Hoplophorella (K.) multirugosaS04; incl. S. cornutus Mahunka 1978S04]

Atropacarus (Kakophthiracarus) tuberculosissimus (Mahunka 1978)N86a, S04 [=Steganacarus tuberculosissimusS04, Hoplophorella (K.) tuberculosissimaS04; incl. H. horrida Mahunka 1984S04, H. meszarosi Mahunka 1988S04, H. (*Kakophthiracarus) tuberosa Mahunka 1988S04, H. verrucosa Mahunka 1987S04]

‘Hoplophorella’ (Hoplophorella) fonseciai (Pérez-Íñigo & Baggio 1980)S04 [=Steganacarus fonseciaiS04, Protophthiracarus fonseciaiN86a]

‘Hoplophorella’ (Hoplophorella) lanceoseta (Balogh & Mahunka 1981)S04 [=Steganacarus lanceosetusS04; incl. H. neglecta Niedbała 1984S04, Atropacarus (Hoplophorella) neglectusN86a]

‘Hoplophorella’ (Hoplophorella) neonominata Subías 2004 [=Protophthiracarus cavernosus Niedbała 2002 non H. cavernosa Mahunka 1987]S04

‘Hoplophorella’ (Hoplophorella) praeoccupata Subías 2004 [=Atropacarus (H.) tuberosus Niedbała & Schatz 1996 non H. tuberosa Mahunka 1988]S04

‘Hoplophorella’ (Hoplophorella) repetita Subías 2004 [=Protophthiracarus reductus Niedbała 1991 nec Steganacarellus reductus Mahunka 1986 nec Hoplophorella reducta Mahunka 1988]S04

‘Hoplophorella’ (Hoplophorella) sculptilis (Niedbała 1988)S04 [=Hoplophthiracarus sculptilisS04, Austrophthiracarus sculptilisN86a; incl. Hoplophthiracarus magnus Mahunka 1988S04]

‘Hoplophorella’ (Hoplophorella) subsellata Balogh & Mahunka 1977S04 [=Protophthiracarus subsellatusN86a; incl. Steganacarus galeatus Balogh & Mahunka 1978S04]

‘Hoplophorella’ (Kakophthiracarus) multituberculata (Balogh & Mahunka 1966)S04 [=Steganacarus multituberculatusS04, Notophthiracarus multituberculatusN86a]

‘Hoplophorella’ (Steganacarellus) ‘heterotricha’ (Niedbała 2000) [=Arphthicarus heterotrichus non H. heterotricha Mahunka 1984]S04

*Type species of generic name indicated

References

[A80] Aoki, J. 1980. A revision of the oribatid mites of Japan. I. The families Phthiracaridae and Oribotritiidae. Bulletin of the Institute of Environmental Science and Technology, Yokohama National University 6 (2): 1–89.

[BB92] Balogh, J., & P. Balogh. 1992. The Oribatid Mites Genera of the World vol. 1. Hungarian Natural History Museum: Budapest.

[G34] Grandjean, F. 1934. Phthiracarus anonymum, n. sp. Revue Française d’Entomologie 1 (1): 51–58.

Liu, D., & Z.-Q. Zhang. 2013. Atropacarus (Atropacarus) niedbalai sp. nov., an extreme case of neotrichy in oribatid mites (Acari: Oribatida: Phthiracaridae). International Journal of Acarology 39 (6): 507–512.

[M98] Michael, A. D. 1898. Oribatidae. In: H. Lohmann (ed.) Das Tierreich. Eine Zusammenstellung und Kennzeichnung der rezenten Tierformen vol. 3. Acarina pp. 1–93. R. Friedländer und Sohn: Berlin.

[N83] Niedbała, W. 1983. Phthiracaridae nouveaux de l’Ouganda (Acari, Oribatida). Folia Entomologica Hungarica 44 (1): 109–123.

[N84] Niedbała, W. 1984. Phthiracaridae (Acari, Oribatida) nouveaux d’Asie occidentale. Annales Zoologici 38 (10): 225–241.

[N86a] Niedbała, W. 1986a. Catalogue des Phthiracaroidea (Acari), clef pour la détermination des espèces et descriptions d’espèces nouvelles. Annales Zoologici 40 (4): 309–370.

[N86b] Niedbała, W. 1986b. Phthiracaroidea (Acari Oribatida Euptyctima) nouveaux d’Espagne meridionale. Redia 69: 93–104.

Niedbała, W. 1986c. Système des Phthiracaroidea (Oribatida, Euptyctima). Acarologia 27 (1): 61–84.

[N91] Niedbała, W. 1991. Preliminary hypotheses on the biogeography of the Phthiracaroidea (Acari, Oribatida). In: Dusbábek, F., & V. Bukva (eds) Modern Acarology: Proceedings of the VIII International Congress of Acarology, held in České Budĕjovice, Czechoslovakia, 6–11 August 1990 vol. 2 pp. 219–231. SPB Academic Publishing: The Hague.

[N01] Niedbała, W. 2001. Study of the diversity of Ptyctima (Acari: Oribatida) and quest for centres of its origin: the fauna of the Oriental and Australian regions. In: Halliday, R. B., D. E. Walter, H. C. Proctor, R. A. Norton & M. J. Colloff (eds) Acarology: Proceedings of the 10th International Congress pp. 143–148. CSIRO Publishing: Melbourne.

[N06] Niedbała, W. 2006. Supplement to the knowledge of ptyctimous mites (Acari: Oribatida) from Australian region. Annales Zoologici 56 (Suppl. 1): 99–156.

[N07] Niedbała, W. 2007. Ptyctimous mites (Acari, Oribatida) of Costa Rica. In: Morales-Malacara, J. B., V. M. Behan-Pelletier, E. Ueckermann, T. M. Pérez, E. G. Estrada-Venegas & M. Badii (eds) Acarology XI: Proceedings of the International Congress pp. 39–42. Instituto de Biología and Faculdad de Ciencias, Universidad Nacional Autónoma de México, Sociedad Latinoamericana de Acarología: México.

Schmelzle, S., R. A. Norton & M. Heethoff. 2015. Mechanics of the ptychoid defense mechanism in Ptyctima (Acari, Oribatida): one problem, two solutions. Zoologischer Anzeiger 2015: 27–40.

[S93] Selden, P. A. 1993. Arthropoda (Aglaspidida, Pycnogonida and Chelicerata). In: Benton, M. J. (ed.) The Fossil Record 2 pp. 297–320. Chapman & Hall: London.

[S04] Subías, L. S. 2004. Listado sistemático, sinonímico y biogeográfico de los ácaros oribátidos (Acariformes, Oribatida) del mundo (1758–2002). Graellsia 60 (número extraordinario): 3–305.

Subías, L. S. 2019. Nuevas adiciones al listado mundial de ácaros oribátidos (Acari, Oribatida) (14a actualización). Revista Ibérica de Aracnología 34: 76–80.

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