Minimamichaelia subnuda ( Berlese, 1910 ), 2025

Minimamichaelia subnuda ( Berlese, 1910) comb. nov.

( Figs. 27A–D, 28A–D, 44D, 52E–H)

Michaelia subnuda Berlese, 1910: 201 , fig. 20, Italy, Florence, Boboli, moss.

Laminamichaelia sp. nr. subnuda ( Berlese, 1910) .— Walter & Latonas 2012: 62; Walter & Lumley 2021: 74, Alberta.

Bimichaelia subnuda .—Vitzhum 1929: 57, Germany; Schweizer 1951: 57, Switzerland; Willmann 1956: 233, Czech Republic.

Bimichaelia? subnuda .—Thor 1931: 230, Norway; Grandjean 1943: 19, France;? B. s., Marshall

& Kevan , 1964: 61, Quebec, woodland humus, 170 ex.

Bimichaelia disetosa McDaniel 1980: 177 View in CoL , figs. 1–6, USA, South Dakota; Vázquez Rojas 2002: 20, Veracruz, B. d. McDaniel, 1979, wrong year; Vázquez-Rojas et al. 2016: 21, Quintana Roo; syn. nov.

Laminamichaelia disetosa View in CoL .— Uusitalo 2010: 69.

Description. Dorsum (n= 2 females, Figs. 27A, B, 51C, 52E–G). Length 175–310 µm; large lamellae clumped in groups i.e. reticular pattern is absent; easily discernible setae on dorsal segments of C, D, E and F mostly short with about ten long and several short cilia; cilia of the setae on caudal segments along an elongated shaft; crista clear prodorsal shield absent, integument of sensory area only poorly differentiated, less than ten long cilia basally on prodorsal setae vi, sce, exp and in, filamentous sensilla ve densely barbed.

Venter ( Fig. 27C, D). Ciliated setae smaller than on dorsum; genital valves each with 5–7 genital setae; anal setae 3–4 per valve.

Gnathosoma ( Fig. 28A). Chelicerae straight, relatively short; subcapitulum with 2 pairs of setae or slightly neotrichous; palpal solenidion in contact with two eupathidia.

Legs ( Figs. 28B–D, 44D, 52H). Solenidial formula for tarsi, tibiae, genua and femora on legs I, II, III and IV, respectively: 2B-2B-0-0, 2B1C-2B-2B-1B, 3\5C-1B2C-1\2C-1\2C, 3\5C-1B-0-0, knob-like famulus I abaxial to solenidion ω2.

Material examined. 2 females as Laminamichaelia nr. subnuda from Point Proctor, Moose Pasture Research Site, 8 km W Chipman, Lamont Co., 53°39’ 37’N 112°45’21’’W, Alberta, Canada, 13 April 2008, David E. Walter, slides: (9) TMS: M00016838 and (10) TMS: M00016837 at the Royal Alberta Museum, Edmonton, Alberta.

3 adults as Bimichaelia disetosa , from shelter belt, ¼ miles N Dakota state line, highway 83, Cambell Co., South Dakota, USA , 25 May 1978, B. McDaniel, collection numbers: TAMU-ENTO X1645197, # X1648035, # X1645476 (used for drawings), deposited at the Texas A&M University Insect Collection, Department of Entomology , 2475 TAMU, College Station, Texas 77843, U.S.A.

Several high-quality photos of 4 specimens as Bimichaelia disetosa from leaf litter dunes, low forest and medium-sized forest, CICOLMA (Centro de Investigaciones Costeras La Mancha), 19°30’N 96°37’W, Veracruz, Mexico, 31 August 1991, 3 September 1991, 13 June 1992, Ignacio Mauro Vázquez Rojas; 1 specimen as Bimichaelia disetosa from leaf litter, low tropical forest floodable (Selva Baja inundable), JBPM ( Jardin Botánico de Puerto Morelos), 20°50’29,9’’N 86°54’ 10,3’’W, Puerto Morelos, Quintana Roo GoogleMaps , Mexico, 28 January 2015, María Magdalena Vázquez; 1 specimens from Selva Baja inundable (Sample M 3B), Sian Ka’an, Quintana Roo , Mexico, 10 January 1995, María Magdalena Vázquez. Mexican material is deposited at the LAAH (Laboratorio de Acarología ” Anita Hoffmann ”), Faculty of Sciences at UNAM (Universidad Nacional Autonóma de México), Mexico City .

Differential diagnosis. The small size, non-reticulate dorsal pattern of middle-sized lamellae, holotrichous prodorsum, and setae of the caudal segments with an elongated shaft characterise Minimamichaelia subnuda , as well as the number of baculiform solenidia on the legs. The species can be segregated from the other species with non-reticulate dorsal patterns ( Fig. 55, undescribed so far) by the prominent, button-like naso and the solenidial formula: two baculiform solenidia on tibia II being side by side, abaxial being smaller, the insertion points are in the middle of the segment and the solenidia are short.

Remarks. Members of the Minimamichaelia have been reported from Europe, North America, South Africa, and Australia ( Uusitalo 2010: 69).

The holotype and four paratypes of Bimichaelia disetosa , collected by McDaniel (1980) from prairie grassland in South Dakota, USA, were not available for examination. Prof. Burruss McDaniel (1928–2004) failed to mention the deposition place, and the material is neither in the Insect Collection of South Dakota State University where he used to work in the eighties (Prof. Paul J. Johnson, in litt.), nor in the Texas A&M University Insect Collection where McDaniel donated his collection upon his retirement some 33 years ago (Dr. Karen Wright, in litt.). However, three extra specimens on slides as Bimichaelia disetosa from TAMU, collected, determined and confirmed on labels by McDaniel’s own handwriting were a good substitute for the type material. The figures of this article are drawn from one of those specimens.

Synonymisation of Bimichaelia disetosa : A) Differences in earlier reported body lengths of subnuda 175–220 µm ( Uusitalo 2010: 70) vs. disetosa 322–325 ( McDaniel 1980: 177) may be due to 1) sex (males are smaller), 2) preparation process (specimens may be expanded when flattened, e.g. 444 µm in fig. 27B) or 3) measuring points (from caudal end to the tip of naso as here vs. to the tip of hood). B) The knob-like famulus I (ε) is (always) present and abaxial to solenidion ω2 (but absent from the original description of B. disetosa ). C) Smaller one of the two baculiform solenidia on tibiae I, II and III is parallel and intimately close to larger one and easy to overlook by light microscopy, and the tiny baculiform solenidion σ1 of genu II is present abaxially on segment (but absent from the original description of B. disetosa ). The observed numbers of ceratiform solenidia on genu I, femur I and genu IV were 5, 3 and 1, respectively, whereas the numbers were 3, 5 and 2 in the original picture of B. disetosa , but the intraspecific variation of the numbers is unknown in these rarely collected species. D) Ventral habitus and number of genital and anal setae per valve (5–6 and 4, respectively) are similar in the American and European materials.

The solenidion on femur II on Minimamichaelia subnuda was interpreted as ceratiform based on figure 116 in Uusitalo (2010) and was also considered as such in the phylogenetic analysis of the family (character state 59/4). However, the Figure 42D of this article clearly shows that there is a baculiform solenidion on femur II.

Genus Quartusmichaelia gen. nov.

Type species: Michaelia setigera Berlese, 1904: 13 , fig. 10, Italy, Florence, rotten Castanea wood.

Differential diagnosis. This genus is closely related to Laminamichaelia by having a reticulate pattern, multiciliate (or lanceolate) setae surrounded by polygonal or roundish loops, formed by primary pattern of large lamellae, and a secondary pattern, formed by transversely packed small lamellae ( Fig. 53A–H). However, species in the genus Quartusmichaelia have only one pair of setae on the sclerotised in -area, i.e. prodorsal neotrichy is concentrated in the soft parts (if there are any additional setae), usually on the anterior rim of the prodorsum; and there are two baculiform solenidia on tarsi I, the anterior one being modified (hook-like or S-shaped).

In comparison to Laminamichaelia sensu stricto, both the in -area and soft prodorsum are neotrichous and there are usually three baculiform solenidia on tarsi I ( Fig. 53I–L); and the dorsal setae are easily discernible because of several elongated cilia per seta. All dorsal setae of Bimichaelia have less than ten, mainly short barbs basally, which are difficult to discern against the intricate cuticular pattern ( Fig. 52A). The prodorsum in the Bimichaelia and Minimamichaelia is holotrichous ( Fig. 52B, F). Integumental ridges are parallel and without granulae and laminae in Glabromichaelia ( Fig. 52K).

Remarks. Considering how easily confusions arose in past attempts to identify specimens within Laminamichaelia sensu lato (see Remarks under Quartusmichaelia dimixsetosa and Laminamichaelia knowltoni ), it seems pertinent to emphasise the character states in the sensory areas and separate Quartusmichaelia and Laminamichaelia sensu stricto into their own genera. The generic clade for setigera was obtained already in Uusitalo (2010: 28, fig. 1) but was left unnamed as its own monotypic genus, i.e. because only one species had been studied in more detail at that time, see Remarks under Minimamichaelia .

Etymology. The name of the genus is a latinised combination of the Latin word ”quartus”, meaning fourth, and “Michael”, referring to the British acarologist Albert Davidson Michael (1836–1927). The name refers to the observed diversity leading to the ever growing number of new genera in the tribe Bimichaeliini since the Berlesian era when only ” Michaelia ” was used ( Fig. 6F).