Chaetodactylus lassulus, phoretic deutonymph, holotype, ex Trichothurgus dubius, Chile, BMOC 96-0916-215
Fig. 1. Chaetodactylus lassulus, phoretic deutonymph, holotype, ex Trichothurgus dubius, Chile, BMOC 96-0916-215 Click to enlarge

Bee Mites : Acari : Acariformes : Sarcoptiformes : Chaetodactylidae : Chaetodactylus

Chaetodactylus lassulus Klimov and OConnor, 2007

Chaetodactylus lassulus Klimov & OConnor, 2007: 824, Figs 12-13 (holotype in KU, paratypes in AMNH, CAS, KU, OSAL, UMMZ); Klimov & OConnor, 2008: 218 (included in key)

Material (show database records). Holotype: HDN - CHILE: Coquimbo, Peñuelas, ex Trichothurgus dubius (Sichel, 1867), on frons, 26 Nov 1955, Wagenknecht, KU, BMOC 96-0916-215. Paratypes: 10 HDNs – same data as holotype; 12 HDN - Choros Bajos, ex T. dubius, on lateral propodeum, 8 Nov 1965, L. E. Peña, AMNH, BMOC 04-0508-153; 10 HDNs - Hacienda Illapel, 600m., ex female Trichothurgus herbsti (Friese, 1905), on pronotum, 7 Nov 1954, L. E. Peña, KU, BMOC 96-0916-216; 10 HDNs - Fray Jorge Rancho, ex Trichothurgus sp., on propodeum, 10 Jul 1950, Ross & Michelbacher, CAS, BMOC 03-0604-010; Región Metropolitana, 2 HDNs - Santiago, ex T. dubius, on pronotum, 1 Jul 1953, L. E. Peña, KU, BMOC 96-0916-214; Unknown province: 10 HDNs - "La Cia", ex T. herbsti, on mesosoma, 24 Oct 1936, E. P. Reed, CAS, BMOC 03-0604-012. Holotype in KU, paratypes in AMNH, CAS, KU, OSAL, UMMZ.
Description (unique character states underlined). Phoretic deutonymph. Longitudinal sclerites on rostral projection (distal extensions of coxal apodemes I) well sclerotized, distinct; rostral parts separated by distinct space and diverging posteriorly. Alveoli ve elongated, situated, outside prodorsal shield. Prodorsal shield small, not extending anteriad of base of se; transversely striated; lateral angles attenuated. Setae si situated outside prodorsal shield, length highly variable from distinctly longer to slightly shorter than 1/2 of distance between their bases. Hysterosomal shield longitudinally striated, except for anterio-lateral part, most lines longer than half of length of hysterosomal shield. No reticulate pattern on hysterosomal shield. Lateral hysterosomal sclerites ventro-lateral, with anterior end situated at anterior level of coxal apodemes III and posterior end at level of posterior apodemes IV. Dorsal setae smooth. Setae c2 situated outside prodorsal shield. Setae c1 and d2 situated outside hysterosomal shield. Setae cp and c2 almost on same transverse level (distance between them usually not exceeding twice the diameter of bases of c2. Setae h3 shorter than femur. Setae h1 and e1 nearly of same length. Coxal setae 1a filiform. Coxal setae 1a, 3a, and 4b situated on soft cuticle. Alveoli of 3a and 4b without surrounding sclerites. Ventral setae 4b distinctly shorter than 3a. Coxal setae 4a almost as long as 3a. Sternal apodeme not bifurcated posteriorly. Posterior apodeme II present, slightly exceeding 1/2 of lateral edge of sternal shield. Proximal and distal extensions of apodemes IV disjunct dorsally. Longitudinal striation between coxae III-IV present. Attachment organ width (including transparent margin) distinctly shorter than distance between 4a. Lateral sclerites of attachment organ not reaching level of 4a. Suckers ad3 (excluding transparent margin) smaller or nearly equal to inner unsclerotized area of suckers ad1+2. Anterior edge of ps2 bases posterior to posterior edge of inner unsclerotized area of suckers ad1+2. Semicircular sclerite distal to base of wa I-II present. Ventral side of claws I-III finely striated. Solenidion σ I shorter than 0.3 of genu I. Setae mG and cG I shorter than combined length of genu and tibia I, both pectinate. Genual setae mG II, pectinate, shorter than combined length of tibia and genu II, longer than mG I, nearly equal to vF II. Femoral setae vF II distinctly shorter than combined length of femur, genu and tibia II. Solenidia ω1 and ω3 distinctly separated, distance exceeds 3 diameters of alveolus of famulus. Tarsal setae la I-II filiform. Tarsal setae wa I-II filiform, slightly widened at base. Genual setae nG III extending end of genu, smooth. Solenidion σ III absent, represented by alveolus. Seta s III subapical. Solenidion φ IV shorter than genu IV. Tarsal setae s and w IV present, uniform in length and width, both shorter than maximum width of tarsus IV. Tarsal setae f and e IV vestigial or absent. Tarsus IV about 3 times longer than its basal width. Other instars unknown.
Diagnosis. The new species differs from all known species of Chaetodactylus by the autapomorphic characters indicated in the description above (underlined). The relative lengths of setae mG II and vF II (shorter than combined length of femur, genu and tibia II) indicates that the new species belongs to the species group primarily associated with Lithurgus. Beside the autapomorphies, it differs, from all species of this group by the well developed posterior apodemes II, which exceed half of the lateral edge of the sternal shield. The position of setae c1 and d2 outside the hysterosomal shield and the elongation of tarsi I-II (as a result, solenidia ω1 and ω3 become distinctly separated, the distance between them exceeding 3 diameters of alveolus of famulus) are shared with two undescribed species associated with Lithurgus from the New World. Setae d2 (but not c1) are also situated outside the hysterosomal shield in three species associated with Lithurgus (C. ludwigi (Trouessart, 1904), C. dalyi Fain, 1974, and related undescribed species from the Neotropics) and one undescribed species associated with Osmia. Ventral striation of claws I-III is shared with an undescribed species associated with Anthidium from Chile.
Morphological variation and abnormalities. The lengths of setae si and other long dorsal idiosomal setae are extremely variable. For instance, setae si may be as long as the distance between them or shorter than half of this distance. This variation is not geographic or host related and occurs within mites phoretic on the same host. Setae si are touching the hysterosomal shield (BMOC 96-0916-214#1). Setae f2 are situated outside the hysterosomal shield (BMOC 96-0916-153#5).
Distribution (show map). Chile: Coquimbo (Peñuelas) (type locality), Región Metropolitana.
Trichothurgus dubius (Sichel, 1867) (type host)
Trichothurgus herbsti (Friese, 1905)
T. sp. (identified as a new species by Moldenke)
Etymology. Lassulus (worn out) is a Latin adjective and refers to the reduced size of the prodorsal shield.

Klimov, P. B. & B. M. OConnor. 2007. Ancestral area analysis of chaetodactylid mites (Acari: Chaetodactylidae), with description of new early derivative genus and six new species from the Neotropics. Annals of the Entomological Society of America.100: 810-829.
Klimov, P. B. & B. M. OConnor. 2008. Morphology, evolution, and host associations of bee-associated mites of the family Chaetodactylidae (Acari: Astigmata), with a monographic revision of North American taxa. Miscellaneous Publications Museum of Zoology University of Michigan.199: 1-243.



B. OConnor and P. Klimov ©
Created: Jun 07, 2011
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