Balaustium murorum, photographed by Ozuma.

Belongs within: Erythraeoidea.

The Balaustiinae are a group of erythraeid mites characterised by the presence of special sensory pits, called urnulae, on the main body. Members of the Australasian genera Microsmaris and Wartookia have two pairs of urnulae, one pair posterolateral to the eyes and the other more posteriorly on the opisthosoma; the Holarctic genera Balaustium and Neobalaustium possess only the anterior pair. Neobalaustium bears the urnulae at the posterolateral corners of a triangular elevation of the propodosoma, the periscutum, surrounding the scutum. Microsmaris and Wartookia are distinguished by the shape of the palpal genu which is cylindrical in Microsmaris but shorter and conical in Wartookia. Larvae of the Holarctic genus Balaustium have been recorded feeding from pollen grains by sucking their contents, in contrast to the parasitic habits of other erythraeid larvae (Southcott 1961).

Characters (from Southcott 1961): Adult and nymph with one eye on each side, placed well behind middle of crista, or, if the crista is obsolete or absent, behind the midpoint between the anterior and posterior dorsal idiosomal sensillae. Dorsum of idiosoma with specialized tubular sensory pits, “urnulae”, either 2 or 4 in number; the anterior pair placed posterior to the eyes; the posterior pair, when present, placed posterolaterally and somewhat dorsally upon the idiosoma. Dorsal idiosomal setae simplified, usually ciliated. Pedal tibiae without distal tubercles. Larva with one eye on each side. Crista metopica present upon dorsum of idiosoma, and placed upon a narrow longitudinal shield, or without dorsal shield. Mouth-parts slender, and containing a distinct mass of the well-developed pharyngeal musculature.

<==Balaustiinae [Balaustiidae]
    |  i. s.: ‘Rhyncholophus’ roseus Banks 1894 [=Grognieria rosea]S61
    |         Mypongia Southcott 1961S61
    |           `--*M. brevipes Southcott 1961S61
    |         Fallopia Oudemans 1905 (n. d.)S61
    |           `--*F. porifera (Kramer 1898) (n. d.) [=Rhyncholophus poriferus]S61
    |         Pollux Southcott 1961S61
    |           |--*P. workandae Southcott 1961S61
    |           `--P. cristatus (Womersley 1934) [=Belaustium (l. c. for Balaustium) cristatus, Microsmaris cristatus]H98
    |--+--Wartookia Southcott 1961G91
    |  |    `--*W. rebeccae Southcott 1961S61
    |  `--Microsmaris Hirst 1926G91
    |       |--*M. mirandus Hirst 1926S61
    |       |--M. hirsti Womersley 1934H98
    |       |--M. joannae Hirst 1928 [=M. goannae]H98
    |       `--M. minutus Womersley 1934H98
    `--+--Microsmarialla Khot 1963G91
       `--+--Neobalaustium Willman 1951G91
          |    `--*N. caspersi Willmann 1951S61
          `--Balaustium Heyden 1826G91, H98 [=Belaustium (l. c.)S61; incl. Monotrombidium Krausse 1924S61]
               |--*B. murorum (Hermann 1804)SB63 [=Trombidium murorumH98, Belaustium murorumH01]
               |--B. aequalipes Schweizer & Bader 1963SB63
               |--B. anomalus Schweizer & Bader 1963SB63
               |--B. antarcticum (Trägårdh 1907) [=Erythraeus antarcticus]S61
               |--B. aonidiphagus (Ebeling 1934) [=Erythraeus aonidiphagus, B. aonidaphagus (l. c.)]S61
               |--B. araneipes Cooreman 1956 (see below for synonymy)S61
               |--B. araneoides (Berlese 1910) [=Achorolophus araneoides]S61
               |--B. barloventensis Haitlinger 2004F05
               |--B. basiliense Schweizer & Bader 1963SB63
               |--B. brevipalpe Schweizer & Bader 1963SB63
               |--B. bulgariense Oudemans 1926 [=Belaustium (l. c.) bulgariense]S61
               |--B. crassitarsum Schweizer 1951SB63 [=Abrolophus crassitarsusS61]
               |--B. ‘cristatum’ Meyer & Ryke 1959 non Belaustium cristatus Womersley 1934G91
               |--B. curtipapillum Schweizer 1951SB63
               |--B. densipapillum Schweizer 1951SB63
               |--B. engadinense Schweizer & Bader 1963SB63
               |--B. evansi Schweizer & Bader 1963SB63
               |--B. florale Grandjean 1947S61
               |--B. graminum Meyer & Ryke 1959G91
               |--B. handschini Schweizer & Bader 1963SB63
               |--B. illustre (Koch 1854) [=Rhyncholophus illustris]S61
               |--B. jurassicum Schweizer & Bader 1963SB63
               |--B. laevicristatum Schweizer & Bader 1963SB63
               |--B. longipapillum Schweizer 1951SB63
               |--B. longipes Schweizer & Bader 1963SB63
               |--B. longum Schweizer 1951SB63 [=Abrolophus longusS61]
               |--B. madeirense Willmann 1939S61
               |--B. malpaisesensis Haitlinger 2004F05
               |--B. medicagoense Meyer & Ryke 1959H01
               |--B. miniatum (Hermann 1804)SB63 (see below for synonymy)
               |--B. neomurorum Schweizer 1951SB63
               |--B. obtusum Trägårdh 1931S61 [=Belaustium obtusumT31]
               |--B. perifi Schweizer & Bader 1963SB63
               |--B. perlongum Schweizer 1951SB63 [=Abrolophus perlongusS61]
               |--B. putmaniWWO01
               |--B. quadrisetum Schweizer & Bader 1963SB63
               |--B. quinquesetum Schweizer & Bader 1963SB63
               |--B. raripapillum Schweizer 1951SB63
               |--B. rhopalicum (Koch 1837) [=Rhyncholophus rhopalicus]SB63
               |--B. sabulosum (Halbert 1915) [=Rhyncholophus sabulosus]SB63
               |--B. southcotti Feider & Chioreanu 1977G91
               |--B. submurorum Schweizer & Bader 1963SB63
               |--B. subquisquiliarum Schweizer & Bader 1963SB63
               |--B. trisetum Schweizer & Bader 1963SB63
               |--B. unidentatus (Trägårdh 1904) [=Erythraeus unidentatus, Rhyncholophus unidentatus]SB63
               `--B. unisetum Schweizer & Bader 1963SB63
Nomen nudum: Balaustium araneoides Willmann 1951 nec Achorolophus araneoides Berlese 1910 nec Rhyncholophus araneoides Halbert 1920S61

Balaustium araneipes Cooreman 1956 [incl. Rhyncholophus araneoides Halbert 1920 non Achorolophus araneoides Berlese 1910]S61

Balaustium miniatum (Hermann 1804)SB63 [=Trombidium miniatumSB63, Abrolophus miniatusS61, Microtrombidium (Enemothrombium) miniatumG96, Rhyncholophus miniatusSB63, Ryncholophus (l. c.) miniatusS61]

*Type species of generic name indicated


[F05] Fernández, J. 2005. Noticia de nuevos táxones para la ciencia en el ámbito Íbero-Balear y Macaronésico. Nuevos táxones animales descritos en la península Ibérica y Macaronesia desde 1994 (IX). Graellsia 61 (2): 261–282.

[G91] Gabryś, G. 1991. Intergeneric relationships within Erythraeidae (Acari, Actinedida). 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. 207–212. SPB Academic Publishing: The Hague.

[G96] Gabrys, G. 1996. Does Enemothrombium Berlese, 1910 (Microtrombidiidae) have the right to exist? In: Mitchell, R., D. J. Horn, G. R. Needham & W. C. Welbourn (eds) Acarology IX vol. 1. Proceedings pp. 363–365. Ohio Biological Survey: Columbus (Ohio).

[H98] Halliday, R. B. 1998. Mites of Australia: A checklist and bibliography. CSIRO Publishing: Collingwood.

[H01] Halliday, R. B. 2001. Systematics and biology of the Australian species of Balaustium von Heyden (Acari: Erythraeidae). Australian Journal of Entomology 40: 326–330.

[SB63] Schweizer, J., & C. Bader. 1963. Die Landmilben der Schweiz (Mittelland, Jura und Alpen): Trombidiformes Reuter, mit 217 Arten und Unterarten und 193 Originalzeichnungen. Denkschriften der Schweizerischen Naturforschenden Gesellschaft [Mémoires de la Société Helvétique des Sciences Naturelles] 84 (2): i–vi, 209–378.

[S61] Southcott, R. V. 1961. Studies on the systematics and biology of the Erythraeoidea (Acarina), with a critical revision of the genera and subfamilies. Australian Journal of Zoology 9: 367–610.

[T31] Trägårdh, I. 1931. Acarina from the Juan Fernandez Islands. Natural History of Juan Fernandez and Easter Islands 3 (4): 553–628.

[WWO01] Wohltmann, A., H. Witte & R. Olomski. 2001. Organismal patterns causing high potential for adaptive radiation in Parasitengonae (Acari: Prostigmata). 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. 83–99. CSIRO Publishing: Melbourne.

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