Review of the mite genus Krantzolaspina Datta & Bhattacharjee (Mesostigmata, Parholaspididae) with re-description of K. angustatus comb. nov. (Ishikawa) from Indonesia

Abstract Herein, we update the diagnosis and description of the genus Krantzolaspina Datta & Bhattacharjee and provide a list of the three valid species including new combinations and synonyms, as follows: 1) Krantzolaspina angustatus (Ishikawa, 1987) comb. nov. (= Indutolaelaps jiroftensisHajizadeh et al., 2017syn. nov.), 2) K. rebatii Datta & Bhattacharjee, 1989 and 3) K. solimani (Metwali, 1983) comb. nov. Finally, we re-describe K. angustatus (Ishikawa, 1987) comb. nov. based on the holotype from Japan, voucher specimens from Iran and additional females that we found in soil samples from oil palm plantations in Sumatra, Indonesia.

Despite the remarkable faunal diversity of the oriental region and numerous reported species of parholaspidid mites, there are shortcomings in the old species descriptions (lack of leg chaetotaxy, information on external poroidotaxy and adenotaxy of the idiosoma). For the previous, we decided to add information and organised the monotypic genus Krantzolaspina, based on available specimens, photographs from paratypes, original description and illustrations. For this reason, in the present work, a re-description of Krantzolaspina angustatus comb. nov. based on holotype, review of the generic concept based on type material and literature, a new synonymy and a list of valid species with some comments is presented.

Material and methods
This study forms part of an investigation on soil and canopy arthropods of rainforests and agricultural systems in Jambi Province, Sumatra, Indonesia and was conducted within the framework of the interdisciplinary project "Ecological and socioeconomic functions of tropical lowland rainforest transformation systems (Sumatra, Indonesia)" -EFForTS. For more details on the study region and the experimental design of the project see Drescher et al. (2016).
Mites were extracted from soil of oil palm plantations in the vicinity of Bukit Duabelas National Park, Jambi Province, Sumatra, Indonesia. Soil samples (1-3 cm depth) were taken using a spade and each consisted of a core of 16 × 16 cm area. Mites were extracted from samples using the high gradient canister method described in Kempson et al. (1963). All specimens were collected in November 2013 by B. Klarner. Mites were stored in 70% ethanol until slide-mounting in Hoyer's medium. For each mite, the gnathosoma was separated from the idiosoma and mounted next to it on the same slide.
Photographs and measurements were made using an Axiolab 5 phase contrast Zeiss microscope with an Axiocam 105 HD digital camera and Nikon Eclipse Ci connected to a computer-controlled digital camera Sight Ds-L3. Stacks of images were taken for each mite, using manual control of the focal plane. Selected images were combined using Zerene Stacker, version 1.04 (Zerene Systems, LLC 2009-2014. In some cases, images captured from different regions of the body were combined using the 'photomerge' function in Adobe Photoshop, version 2015 (16.0 or 20150529.r.88; Adobe Systems Inc., San Jose, USA). Digital drawings were prepared with Adobe Illustrator, version CC 2015 (19.0.0), based on (combined) photographs.
All measurements are given in micrometres (μm) and include the range (minimum-maximum). Lengths of shields were measured along their midlines and widths at their widest point, except for the sternometasternal shield which was measured at the level of insertion of setae st2 and genitiventrianal shield between bases of JV1-2. Leg measurements were taken from the proximal margin of the coxa, along the midline of each segment, to the tip of the claw. Notations of body structures and idiosomal chaetotaxy follow Lindquist and Evans (1965) as adapted by Moraza and Peña (2006) and Marchenko (2016). Leg chaetotaxy follows  and Evans and Till (1965) and palps Evans and Till (1963). Idiosomal and peritrematal shield notations for porelike structures (gland pores and poroids/lyrifissures) follow the system of Athias-Henriot (1971) for the ventral idiosoma and Athias-Henriot (1975) for the dorsal idiosoma.
Specimens of examined K. angustatus comb. nov. are deposited at NSMT (National Science Museum Natural History), Tokyo, Japan, the Holotype and voucher specimens at ESALQ (Escola Superior de Agricultura Luiz de Queiroz -Universidade de São Paulo), São Paulo, Brazil. Other collected materials are deposited at LIPI (Indonesian Institute of Science), Cibinong, Indonesia; SMNG (Senckenberg Museum), Görlitz, Germany; OSAL (Ohio State Acarology Collection), Columbus, USA and in ANIC (Australian National Insect Collection) Canberra, Australia. Additional photos of the species are digitally deposited in the online database Ecotaxonomy, accessible at http://www.ecotaxonomy.org.
The updated diagnosis and description of the genus were prepared after consulting the original description of the genus Krantzolaspina (Datta and Bhattacharjee 1989), as well as species descriptions (Metwali 1983, Ishikawa 1987a, Datta and Bhattacharjee 1989, Hajizadeh et al. 2017.
Male. Unknown. Description. Female. Dorsal idiosoma. Dorsal shield 340-561 μm long, broad anteriorly, gradually tapering posteriorly, anterior margin almost straight/truncate, partially covering idiosoma, leaving with the lateral and posterior margins of the soft integument broadly or narrowly exposed; shield mostly reticulate. Dorsal shield hypotrichous, bearing 32 (J5 and S5 slightly pilose in K. angustatus comb. nov.) or 36 pairs of smooth setae, most setae long and of similar length. Unsclerotised cuticle with 10-15 pairs of r, R and/or UR setae combined, smooth and moderately long (UR setae slightly pilose in K. angustatus).
Gnathosoma. Subcapitulum with the corniculi well sclerotised, elongated and hornlike. Internal malae bifurcate, well separated from each other, densely fimbriated on outer margin and with apices slightly shorter than corniculi. Deutosternal groove with multi-dentate transverse rows, subcapitular setae smooth and aciculate, h1-h3 often longer than h2 and pc. Surface posterolaterad to seta pc with a pointed spine-like process or absent (simply flat). Epistome with a median projection and lateral margins irregularly serrate or may be smooth. Chelicera chelate-dentate; movable digit often bearing two teeth. A setiform pilus dentilus; smooth dorsal cheliceral seta, dorsal lyrifissure, a pair of unequal plumose arthrodial brushes or one plumose arthrodial brush and a narrow fringed arthrodial corona at base of the movable digit are present. Palp trochanter with a small pointed spine-like process in the ventral surface and with setae v1 and v2 slightly thickened and long, in contrast with setae of the other palp segments; palp tarsal claw three-tined.
Legs chaetotaxy as in diagnosis (see above).

Re-description
Krantzolaspina angustatus (Ishikawa, 1987) comb. nov. Diagnosis. Female. Dorsal shield entire, mostly reticulate (except the anteromedial region which is smooth), partially covering the idiosoma, broad anteriorly and posteriorly narrowing; shield bearing 32 pairs of setae, most setae moderately long and smooth, except j1-2 and z1 which are slightly shorter and setae S5 and Z5 slightly pilose. Unsclerotised lateral cuticle of the idiosoma with a total of 15 pairs of smooth setae of similar length, except five pairs of UR setae slightly pilose, the pairs of setae r6 and R1 slightly shorter than r5-7 plus seven pairs of UR setae. In the idiosoma ventre, all setae aciculate and smooth, except JV4-5 and ZV4-5 which are pilose. Presternal area with two pairs of free and presternal platelets. Sternometasternal shield mostly reticulate and covered by semi-rounded cells in the lateral margins, bearing four pairs of setae. Peritrematal shield anteriorly free, fused to the sternometasternal shield between coxae I-III, posteriorly fused with the parapodal shield and extended beyond posterior margin of the coxae IV, region of peritrematal + parapodal shield reticulate and covered by some semi-rounded cells; peritreme extending between coxae I-II at level of st1. Genitiventrianal shield longer than wide, reticulate, flask-shaped and bearing four pairs of setae st5, JV1-3, as well as three circumanal setae pa and po. Soft opisthogastric ventral cuticle with six pairs of setae JV4-5, ZV2-5. Metapodal platelets free, small and elliptical in shape. Deutosternal groove with six transverse rows, surface of the gnathosoma with pointed spine-like process similar to the ventral surface of the palp trochanter. Epistome with median projection bifurcate or trifurcate distally, lateral edges finely and irregularly serrate. Cheliceral digit movable and fixed with four and two teeth, respectively, base of movable digit with a plumose arthrodial brush and a narrow fringed arthrodial corona. Palp tarsal claw threetined. Pretarsus I reduced or absent and pretarsi II-IV with pretarsi well-developed.
Remarks. Krantzolaspina is a well-defined genus by the unique combination of characters stated above (see diagnosis of the genus). However, a number of characters are also present in other dermanyssine families, for example, well-developed arthrodial brush(es) is/are also present in macrochelid mites, a sternometasternal shield bearing st1-st4 is shared with species of Pachylaelapidae (Mašán and Halliday 2014) and Ologamasidae (Castilho et al. 2016) and the fusion of genital + ventral + anal shields forming a genitiventrianal shield is shared with two genera of Laelapidae (Ololaelaps and Oloopticus) (Beaulieu et al. 2019).
One particular feature of Krantzolaspina is the pointed spur-like process present on the palp trochanter and this character is important for recognising the genus. However, a similar process is present in species (and all post-embryonic stages) of the monotypic family Megalolaelapidae (Megalolaelaps), in which the palp trochanter typically bears a large anteroventral horn-like projection. Unfortunately, the function of these processes of the palp trochanter in Krantzolaspina and Megalolaelaps is unknown (Mašán andHalliday 2014, Cómbita-Heredia et al. 2018). It should be noted that members of Megalolaelapidae are more similar morphologically to Pachylaelapidae and to Macrochelidae of the genus Neopodocinum Oudemans (Macrochelidae) than to Parholaspididae (Cómbita-Heredia et al. 2018).

Distribution of Krantzolaspina spp.
Krantzolaspina species have been collected from soils, mainly disturbed soil and in countries of Southern Asia. However, its distribution is isolated since they are present in Iran, Philippines and recently recorded in Indonesia (see details of locality type and other records, Table 1). A similar pattern of isolated distribution is present in other species of the parholaspidid family (e.g. Holaspina alstoni and Parholaspis kewensis, P. meridionalis) which were collected in botanical gardens from England where these records were based on accidental introduction (Ishikawa 1980c, Latifi et al. 2006) and potentially facilitated by human activity (Latifi et al. 2006). Hypothetically, we believe that these records of Krantzolaspina are based on introduced specimens through the trading of vegetal material including soil where they inhabit. (Ishikawa, 1987) comb. nov.

Notes on Indutolaelaps jiroftensis Hajizadeh et al., 2017 syn. nov. of K. angustatus
This species was described in the genus Indutolaelaps Karg, 1997 (Leptolaelapidae), based on a genitiventrianal shield, an epistome with an anteriomedial extension, wider at the base and acute distally and a palp tarsal claw three-tined (Hajizadeh et al. 2017). The misplacement of I. jiroftensis in the genus Indutolaelaps may suggest some genuslevel similarity of Indutolaelaps and Krantzolaspina. These two genera indeed share several conspicuous characters such as similar shape of the genitiventrianal shield, presence of two pairs of presternal platelets, sternometasternal shield bearing st1-4, parapodal shield welldeveloped and fused with peritrematal shield, epistome with a narrow median projection and lateral margins serrate and 3-tined palptarsal claw. However, both genera which belong to different families can be distinguished by the combination of characters given in Table 2, such as arthrodial process, number of presternal platelets and preanal and dorsal setae.
Further, the synonymy of I. jiroftensis is supported in that it has 32 pairs of dorsal setae, two pairs of presternal platelets, sternometasternal and genitiventrianal shield with four pairs, as well a distinct ornamentation pattern (Hajizadeh et al. 2017 pp 670-671), which are diagnostic characters of the genus Krantzolaspina and specifically of K. angustatus. Additionally, the characters present in their drawings (figs 3, 5-7) and our photos (Figs 3B, 4B, E, H, K) of I. jiroftensis (Hajizadeh et al., 2017) match the characters from the holotype of K. angustatus (see Figs 3A, 4A, D, G, J).

Notes on Krantzolaspina rebatii Datta & Bhattacharjee, 1989
Krantzolaspina rebatii Datta & Bhattacharjee, 1989: 411 The holotype of K. rebatii was deposited according to Datta and Bhattacharjee (1989) in "Collection of Animal Ecology Laboratory, Department of Zoology, Gauhati University, Guwahati, India"; however, we were unable to locate this type specimen despite significant efforts. A careful study of type material will be essential to identify the diagnostic traits of that species.
Focusing on the original description, we like to mention some discrepancies and/ or mistakes that we found between the text and illustrations as follows: (1) Dorsal shield: "36 pairs of setae" is indicated in the text (Datta and Bhattacharjee 1989:411); however, their illustration ( fig. 1b) shows only 34 apparent pairs of setae, although five represented only by sockets (presumably because the setae had fallen off). In addition, it is unclear whether the dorsal shield is smooth or not, as any type of ornamentation seems to be excluded from their original drawings and text.
(2) Venter: The ornamentation seems to be excluded from their original text, but it looks mostly smooth in fig. 1a of Datta and Bhattacharjee (1989) as well the lateral region punctate of the sternometasternal shield and the margin anterior of the genitiventrianal shield. The present differential characters are listed in order of importance. 1 All setae are smooth and moderately long, except when mentioned otherwise. * based on the present review; ** based on the original description of Karg (1997). FD -fixed digit; MD -mobile digit.
(3) Legs: Datta and Bhattacharjee (1989) provided an illustration of the legs (Fig. 1i-h), but without accompanying text in the description. The illustrations indicate a reduced number of setae compared with the leg chaetotaxy herein described for K. angustatus (Table 1). We presume that some setae were overlooked and not drawn by Datta and Bhattacharjee (1989).
Neoparholaspulus solimani Metwali, 1983: 459. Metwali (1983 placed this species in the genus Neoparholaspulus, based on some characters that are typical for the genus, such as a genitiventrianal shield and one pair of presternal platelets, as well as one pair of metasternal shields free. In addition, Metwali's description of the species includes "metasternal plate well developed and free". However, the description also states that the sternal shield has four pairs of setae and the illustration shows that the metasternal plates are fused to the sternal shield. We have provisionally placed this species in Krantzolaspina, based on the presence of 32 pairs of setae in the dorsal shield, two pairs of presternal platelets and the assumption that fig. 2 of Metwali (1983) is inaccurate and that the metasternal plates are indeed fused to the sternal shield. Unfortunately, as the type specimens are lost, this interpretation cannot be confirmed (Reham Abo-Shnaf, personal communication).

Krantzolaspina sp.?
Nawar and El-Sherif (1995: 273) re-described the female of a species that they identified as Holaspina solimani and described the male for the first time. Hussein et al. (2002Hussein et al. ( : 1117 reared this species in the laboratory and studied its biology and behaviour. However, the illustrations and description in Nawar and El-Sherif (1995) differ in the grade of fusion of the metasternal plate, as well as the number of setae in the sternal shield from those in Metwali (1983) and we provisionally assume that these two specimens are two different species. Unfortunately, the specimens examined by Nawar and El-Sherif (1995) and Hussein et al. (2002) are lost and this interpretation cannot be confirmed (Reham Abo-Shnaf, personal communication).