Ameroseius plumosus ( Oudemans, 1902b )

Narita, João Paulo Z., Bernardi, Leopoldo F. O., Ferreira, Rodrigo L. & de Moraes, Gilberto J., 2013, A new species of Ameroseius Berlese from Brazil, redescriptions of Ameroseius plumosus (Oudemans) and Ameroseius plumigera (Oudemans) (Acari: Mesostigmata: Ameroseiidae) based on the examination of type material, Journal of Natural History 47 (35 - 36), pp. 2311-2326 : 2317-2321

Ameroseius plumosus ( Oudemans, 1902b)

Seiulus plumosus Oudemans, 1902b: 17 .

Kleemannia plumosus, Oudemans (1930) : 138.

Zercoseius macauleyi Hughes, 1948: 146 , synonymy by Hughes (1961): 246. Primoseius macauley, Womersley (1956) : 116.

Kleemania [sic] plumosus, Hughes (1961) : 246.

Ameroseius plumosus, Westerboer and Bernhard (1963) : 491.

( Figure 3 )

Diagnosis of adult

Palp apotele and corniculus three-tined. Dorsal shield with 28 pairs of setae, all leafshaped and lightly serrate. Distance between the bases of setae J4 about 0.7 times as long as distance between J4 and Z4 of each side. A few setae reach the bases of the subsequent setae of each series. Sternal shield with an inverted “U”-shape, seemingly sub-superficial anteromedian structure. Seta st3 on a platelet, opisthogaster with six pairs of setae, two of which on the ventrianal shield (in addition to circumanal setae). Genu of leg III and tibia of leg IV with 10 setae each.

Adult female ( Figure 3 A–D)

Gnathosoma . Fixed cheliceral digit 23 long, with four relatively large teeth near the base of the digit and apparently two tiny teeth near the apex; movable cheliceral digit 15 long, teeth not discernible. Antiaxial and dorsal lyrifissures not distinct. Epistome with an elongate, acute and smooth central projection. Palp apotele threetined. Deutosternum narrow, transverse rows of denticles not discernible. Corniculi three-tined.

Dorsal idiosoma ( Figure 3 A–C). Dorsal shield entire, totally reticulate; reticula formed by simple lines; 410 long and 260 wide at level of s6; apparently with four pairs of lyrifissures (posteromediad of r5, posterior of J2, posteromediad of S3, mediad of S5). Lengths of dorsal setae: j1 22; j2 25; j3 23; j4 24; j5 30; j6 32; J2 45; J4 47; z2 27; z4 30; z5 30; Z1 32; Z2 32; Z4 46; Z5 50; s1 27; s2 35; s4 30; s5 32; s6 35; S2 35; S3 35; S4 35; S5 45; r2 29; r3 24; r4 30; r5 23. Distance between the bases of setae J4 about 0.7 times as long as distance between J4 and Z4 of each side. A few setae reach the bases of the subsequent setae of each series. All setae leaf-shaped; most very lightly serrate, except j1, distinctly serrate and wider distally than other setae.

Ventral idiosoma ( Figure 3D ). Base of tritosternum six long and six wide, laciniae fused along distal half of their total length (49 long). Sternal shield reticulate over most of its extension, smooth centrally; 82 long at midline and 105 wide at widest level, bearing setae st1 and st2; with an inverted “U”-shaped, seemingly sub-superficial anteromedian structure. Seta st3 on a platelet and seta st4 on unsclerotized cuticle. Genital shield with scanty striae, bearing st5, 80 wide at widest level, sided posteriorly by a pair of lyrifissures. Ventrianal shield reticulate, with reticula much wider than long anteriorly to the anal opening and roughly longer than wide or as long as wide posteriorly, 118 long at the midline and 155 wide at the widest level, bearing Jv2 and Jv3. Unsclerotized cuticle of opisthogaster with setae Jv1, Jv5, Zv1 and Zv2, a pair of lyrifissures (anterior of Jv2) and a pair of elongate metapodal platelets. Lengths of ventral setae: st1 23; st2 23; st3 17; st4 16; st5 15; Jv1 9; Jv2 15; Jv3 8, Jv5 50, Zv1 10, Zv2 13. Seta Jv5 and postanal seta leaf-shaped and serrate, other ventral setae setiform and smooth. Endopodal shield fused to sternal shield except for a triangular remnant platelet between coxae II and III. Exopodal shield distinguishable as a narrow band with projections between coxae II and III and coxae III and IV.

Peritreme and peritremal shield. Peritreme reaching level of j2. Peritremal shield fused to exopodal shield behind stigma; with a large pore at level between coxae II and III (gd3 of Athias-Henriot 1975; gp2 of Lindquist and Moraza 2009).

Legs. All legs with pulvilli and claws. Lengths of the legs: I – 330, II – 270, III – 250, IV – 310. Chaetotaxy of legs I–IV: coxae: 2, 2, 2, 1; trochanters: 6, 5, 5, 5; femora: 12, not discernible, 5, 6 (determination of chaetotaxy was not possible for any of the femora, because of the unfavourable position of the legs in the holotype); genua: 12

(2-3 / 2-2 / 1-2), 11 (2-3 / 1-2 / 1-2), 10 (2-2 / 1-2 / 1-2), 9 (2-2 / 1-3 / 0-1); tibiae: 12 (2-3 / 2-2 / 1-2), 10 (2-2 / 1-2 / 1-2), 9 (2-1 / 1-2 / 1-2), 10 (2-2 / 1-2 / 1-2); tarsi: not counted, 17, 17, 17.

Material examined

Holotype female collected from Vespertilio dasycneme (Boie) ( Chiroptera : Vespertilionidae ), in Sneek, the Netherlands, by A.C. Oudemans, July 1896, deposited at The Netherlands Centre for Biodiversity Naturalis, Leiden, the Netherlands ( RMNH Acari P4303).

Remarks

Oudemans (1930) stated that in July 1896 he collected three mites with lanceolate- or feather-like setae from Vespertilio dasycneme ( Chiroptera : Vespertilionidae ) at Sneek, the Netherlands and that in November 1896 he collected another mite with featherlike setae on Sciurus vulgaris ( Rodentia : Sciuridae ) at Arnhem, the Netherlands. These findings were reported by Oudemans (1902a), when the mites were referred to as Seiulus plumosus [nomen nudum]. In the same year, the mites were described under the same name ( Oudemans 1902b).

In the original description, Oudemans (1902b) referred to certain variations he could observe between the specimens at hand in relation to the number of dorsal shield setae, stating that he could observe a transversal row of setae on the dorsal shield between legs III and IV; in most specimens the row was composed of eight setae, whereas in a single specimen (most certainly the specimen examined in this study) it was composed of only six setae (in his words “no. 3 and 6 being absent”). He was most probably referring to setae j6, z6, s5 and r5 (according to the terminology used in this paper) for the full complete specimens and to the absence of z 6 in one specimen.

According to Oudemans (1930), three different species were included under Seiulus plumosus in its original description. He then referred that name to a female specimen collected from V. dasycneme (examined in this study), that in the original description was mentioned as a female deutonymph [figs 18, 19 of plate 1, and fig. 20 of plate 2 of Oudemans (1902b)]. The remaining specimens collected from V. dasycneme [referred in the original description as protonymphs, figs 15–17 of plate 1 of Oudemans (1902b)] were re-identified in the same publication as Kleemannia pavidus ( Koch, 1839) , whereas the single specimen collected from S. vulgaris [referring to fig. 21 of plate 2 of Oudemans (1902b)] was then described as Kleemannia plumea .

In the redescription of K. plumosus by Oudemans (1930), the author was ambiguous in relation to the number of dorsal shield setae, stating first that there were 29 pairs, and immediately afterward that there were 28 pairs. Our examination of the specimen studied by Oudemans confirmed the presence of only 28 pairs.

Some morphological differences were observed between our examination of the holotype of A. plumosus and redescriptions provided by different authors based on specimens from other countries.

Hughes (1948) described and illustrated Zercoseius macauleyi , based on specimens collected in the UK. Womersley (1956) illustrated a specimen from Australia identified as belonging to that same species, but placing it in Primoseius , a monotypic genus he then described. Hughes (1961) presented the same illustrations given in the original description of the species, synonymizing Z. macauleyi under A. plumosus , which she then placed in Kleemannia (mentioned as Kleemania ). Halliday (1997) provided a brief diagnosis of A. plumosus , taking into account specimens identified as P. macauleyi by Womersley (1956) and other specimens also from Australia. The following characteristics illustrated in those papers suggest Z. macauleyi to be distinct from A. plumosus : dorsal shield setae slightly curved and spear-shaped (except j1), and setae j1–J2 reaching or almost reaching base of the respective closest setae behind. There are some discrepancies in the literature in relation to other characteristics. In the original description of Z. macauleyi and in the redescription of that species by Womersley (1956), the fixed cheliceral digit is mentioned to have and is illustrated as having four teeth (as observed in our examination of the holotype), differing from Halliday (1997) who mentioned the species (referred to as A. plumosus ) to have only three teeth. In the original description of Z. macauleyii and in the redescription by Hughes (1961) the corniculus is described as two-tined, whereas Womersley (1956) describes it as three-tined. We suppose that Hughes (1948, 1961) could have overlooked the third tine, located around the mid length of the corniculus. Also in the original description of Z. macauleyi the sternal shield is mentioned as having a central crescentic-shaped space with a crenulate edge, whereas Hughes (1961) mentioned that some specimens she had available were as originally described, but others did not have that pattern on the sternal shield, and Womersley (1956) made no reference to that pattern, suggesting it to be absent in the specimens he examined. In addition, the illustrations in Hughes (1948, 1961) show the presence of 28 pairs of dorsal shield setae, although Hughes (1961) mentioned the presence of 29 pairs. Hence, Z. macauleyi seems to be different from A. plumosus . However, to prevent mistakes, the holotype of Z. macauleyi should be examined before a definitive conclusion.

Westerboer and Bernhard (1963) redescribed A. plumosus based on specimens collected in Germany, indicating that their podosoma was ornamented with pit-like depressions and that setae j1, j3, j4 and j6 reached the subsequent setae of their series. These characteristics differ from our observation of the holotype, suggesting that this species could also be different from A. plumosus .

Figures

Figure 3. Ameroseius plumosus (Oudemans) female. (A) Dorsal view of idiosoma; (B) detail of seta j1; (C) detail of seta j6; (D) ventral view of idiosoma.