Abstract: Cosmolaelpas qassimensis sp. nov. was collected from soil samples containing leaf litter and soil surrounding the root system of date palm trees during 2013-2014 in Qassim, Saudi Arabia. Monthly survey showed that C. qassimensis was at its highest rate of occurrence (13.96 individuals/ sample) in September. There were no significant differences between average number of mites collected in May, July, August and October, while it was rarely found (1.25 and 0.96 mites/ sample) in January and February, respectively. Immature stages and adult female and male of C. qassimensis sp. nov. were extracted from a pure laboratory culture, which were maintained feeding on the acarid mite, Tyrophagous putrescentiae Schrank and kept at 26±1°C and 70±5% RH. They were illustrated and identified.
INTRODUCTION
Mesostigmatid mites represent an important component of the belowground food web, where they are generally considered to be predators feeding on small arthropods, worms and nematodes (Al-Rehiayani and Fouly, 2005; Joharchi and Halliday, 2011). The laelapid family is considered one of the most important groups of soil predatory mites, where it usually feeds on soil arthropods and nematodes (Walter and Campbell, 2003; Joharchi et al., 2012). Some species in this family ecologically diverse, including obligatory and facultative parasites of vertebrates and insect pathogens (Evans and Till, 1966; Strong and Halliday, 1994; Lindquist et al., 2009).
Genus Cosmolaelaps Berlese consists of a large group of free-living predators in soil (Evans and Till, 1979; Karg, 1995; Ma et al., 2004; Karg and Schrolemmer, 2009; Fouly and Al-Rehiayani, 2011). This genus has been treated in previous studies either as a genus or as a subgenus of Hypoaspis Canestrini, 1885 (Xu and Liang, 1996; Faraji and Halliday, 2013). In 1993, Casanueva raised most of the groups considered as subgenera to the generic level and put them in the subfamily Hypoaspidinae. During the last two decades, many new species of Cosmolaelaps were identified and illustrated by several authors worldwide (Karg, 1995; Fouly et al., 1997; Bei et al., 2003; Ma et al., 2004; Bai and Wang, 2005; Karg and Schrolemmer, 2009; Joharchi and Halliday, 2011; Joharchi et al., 2011, 2012).
Based on literature and updated information, there is rare or no previous knowledge about classification of predatory mites in Saudi Arabia until came Fouly and Al-Rehiayani (2011) who surveyed and described 38 species of predaceous mites belonging to different classification categories. They also described and illustrated two new laelapid species, Hypospis dactylifera and H. zaheri (Fouly and Al-Rehiayani, 2011).
The present study is a part of a project which has the main objective of increasing the knowledge of this poorly studied regional mite fauna, especially that of Laelapidae. Therefore, we illustrated and described female, male and developmental stages of a new species, C. qassimensis sp. nov., which was collected from soil samples under date palm trees Phoenyx dactylifera L. in Qassim district, Saudi Arabia. Specimens on which this study is based were taken from a pure culture which maintained on Tyrophagous putrescentiae as food and deposited in the mite collection of Department of Agricultural Zoology, Faculty of Agriculture, Mansoura University, Egypt.
MATERIALS AND METHODS
Mite collection: Soil samples of 5x2 kg including leaf litter under date palm trees grown at the Research Experimental Station in Melida province, College of Agriculture and Veterinary Medicine, Qassim University were monthly collected from March 2013 till February 2014. Mite individuals were collected by using modified Tullgern’s funnels (Krantz, 1978), then mite individuals were preserved in 70% alcohol until microscope examination.
Identification of Cosmolaealps qassimensis sp. nov.: Morphological study was conducted by using an Olympus Camera DP25 attached to an Olympus Microscope BX51, both are connected to a HP Computer. The nomenclature and chaetotaxy of immature stages, adult male and female of C. qassimensis was pointed out according to the terminology of Evans (1963), Lindquist and Evans (1965), Evans and Till (1966, 1979) and Bregetova (1977).
Statistical analysis: Data of survey was statistically analyzed by one way ANOVA, where Duncan’s multiple range test was used to compare means of collected mite individuals by using Costat Software (1990).
RESULTS
Occurrence of Cosmolaelaps qassimensis sp. nov.: Survey study proved that there were significant differences between average total numbers of C. qassimensis individuals collected from soil sample surrounding root system of date palm trees. Samples collected in September showed the largest number of mites and followed by those collected in June, while February represented the lowest numbers {F = 221.92; df = 11, 108; p = 0.000, where, LSD 0.69 (p = 0.05)}. The present results showed that there were no significant differences between average total numbers of C. qassimensis collected in May, July, August and October (Fig. 1).
Cosmolaelaps Berlese (1903):
| • | Family Laelapidae Trägårdh, subfamily Hypoaspidinae Vitzthum, Tribe Pseudoparasitini Vitzthum |
| • | Cosmolaelaps Berlese (1903), sensu (Evans and Till, 1979) |
| • | Type species, Laelaps claviger Berlese |
| Fig. 1: | Mean total number of Cosmolaelaps qassimensis sp. nov. collected from soil surrounding root system of date palm trees in Qassim region during 2013-2014. Columns have the same letter are not significantly differed (Duncan Multiple Range Test, (p = 0.05)) |
Description of Cosmolaelaps qassimensis sp. nov.
Female: Body light brown in color when alive, idiosoma oval-shape (682 μm long and 526 μm wide). Dorsal shield entire (595.52 μm long and 406.56 μm wide at the level of seta s6 (coxa IV), faintly reticulated in most surface but interrupted by a smooth area between setae j5 and j6, not covering the whole idiosoma. Thirty nine pairs of dorsal setae, 22 pairs of which on podonotum and 17 on opithonotum (Fig. 2). Setae j1 lanceolate (31.72 μm) in addition to 38 pairs of scimitar-like setae including r, s, S and Z setae, which with a blunt side bulge at one third from their bases (Fig. 3a). Dorsal setae length in j-J; z-Z; s-S and r series ranged from 30.64 to 63.12, while setae z1 the shortest (23.60 μm). Three un-paired setae Jx1 (52.56 μm), Jx2 (47.32 μm) and Jx3 (44.84 μm) inserted between J series on opithonotum and two pairs of px2 and px3 setae between J and Z series of each side. Dorsal shield with 10 pairs of pores of various shape and size except a pair of crescent-like pores occurs beside setae Z5. Ten pairs of marginal setae arise on lateral membrane, each with a small projection near their bases (Fig. 2).
Tritosternum with base (32.72 μm) and long pilose laciniae (88.32 μm) (Fig. 3b). Presternal area punctuate with faintly transverse striae. Sternal shield faintly reticulate, longer than wide (116.44 μm long and 104.40 μm wide at the level of setae St2), its anterior corners expand laterally, concave posteriorly, extends distally to middle of coxae III, bearing 3 pairs of simple subequal sternal setae (St1 = 44.64; St2 = 42.88 and St3 = 43.36 μm) and 2 pair of lyriform pores, of which the anterior pair situated at the inner side of St1; the second pair obliquely longer and situated posterior to setae St2. Metasternal setae (St4 = 44.02 μm) arise on a narrow endopodal shield and posterior to a pair of small circular pores (Fig. 4). Genital shield drop-shaped (197.05 μm long and 102.25 μm wide), covered with faintly network striae and with a pair of genital simple setae (32.28 μm). Anal shield subtriangular with 2 pairs of adanal setae (26.88 μm), situated laterally on a line running through the middle of anus. Postanal seta longer than adanals (34.08 μm).
| Fig. 2: | Cosmolaelaps qassimensis sp. nov. dorsal surface of female |
| Fig. 3(a-e): | Cosmolaelaps qassimensis sp. nov., female, (a) Dorsal setae, (b) Tritosternum, (c) Gnathosoma, (d) Tectum and (e) Chelicerae (Scale bar = 50 μm) |
| Fig. 4: | Cosmolaelaps qassimensis sp. nov. ventral surface of female |
Metapodal shield (32.16 μm) club-shaped as twice as long as the secondary one (18.22 μm) (Fig. 4). Two pairs of platelets (para-genital) arise beside genital shield, of which the anterior pair crescent-shaped while the posterior pair circular. Ten pairs of setae inserted on the soft opithogastric membrane, of which 2 pairs of simple setae between genital and anal shields, while the rest with small and sharp projection near their bases. Peritreme well developed, lies between coxa III and IV, with a small circular pore behind the stigma, peritremal plate extends anterodorsally to reach the posterior base of setae z1 (Fig. 4).
Corniculi horn-like (68.82 μm), internal mala well developed. Deutostrnum with eight rows of denticles. Four pairs of hypostomatic setae, of which hyp3 and capitular setae (36.72 μm) anterior hyp1 (33.76 μm) and hyp2 (25.84 μm) (Fig. 3c). Tectum anterior margin triangular, irregularly denticulate with central apical point (Fig. 3d).
Fixed digit of chelicerae (59.44 μm) with a big basal tooth, 7 small teeth plus a distinct pilus dentilis, while movable digit (52.68 μm) with 2 blunt teeth (Fig. 3e).
Legs: Measurements of legs I-IV 546.48, 444.16, 414.88 and 624.80 μm, respectively. Most ventral setae on legs I-IV spine-like. Chaetotactic of femura I-IV 13, 11, 6, 6; genua I-IV13, 11, 9, 9; tibiae I-IV 13, 10, 8, 10, respectively (Fig. 5).
| Fig. 5: | Cosmolaelaps qassimensis sp. nov., Legs I-IV |
| Fig. 6: | Cosmolaelaps qassimensis sp. nov, ventral surface of male |
Male: Smaller than female, length of dorsal shield 449.12 and 305.22 μm wide at the level of coxa IV. Chaetotaxy of dorsal setae as in female. Holoventral shield (364.40 μm long and 106.54 μm wide) faintly reticulated, with 10 pairs of sub-equal simple setae, 2 pairs of crescent-shaped pores as well as a pair of circular pores (Fig. 6).
| Fig. 7(a-b): | Male chelicera (Scale bar = 50 μm) |
| Fig. 8(a-b): | Cosmolaelaps qassimensis sp. nov., larva, (a) Dorsal shield and (b) Ventrum |
Fixed digit with a single blunt tooth near its tip, while the movable one unidentate and fused with extremely long hose-shaped spermatodactyl (142.24 μm long) (Fig. 7a, b). Measurements of legs I-IV 462.24, 334.40, 323.20 and 488.84 μm, respectively. Legs unarmed, structure and chaetotaxy as for female.
Larva: Hypostome with only 2 pairs of setae. Idiosoma (360.16 μm long and 247.36 μm wide), dorsal shield entire smooth, with 14 pairs of simple setae, of which setae z2, Z4 and J5 the longest (Fig. 8a). Tritosternum with 2 laciniae. Ventral surface with 7 pairs of subequal setae. Postanal setae longer than adanals. Peritreme absent. (Fig. 8b). Legs I-III measure 364.20, 249.52 and 246.60 μm, respectively.
| Fig. 9(a-b): | Cosmolaelaps qassimensis sp. nov., Protonymph (a) Dorsal shield and (b) Ventrum |
Protonymph: Hypostome with 3 pairs of setae forming a triangular shape. Tritosternum with 2 laciniae. Idiosoma (433.32 μm long and 320.32 μm wide), divided into smooth subtriangular podonotum with a produced posteriorly 234 μm long and 188.48 μm wide and with 11 pairs of scimitar setae except j1 lanceolate. The opithonotum shield semi-obscure (107 μm long and 126.40 μm wide) with 8 pairs of scimitar setae, of which setae Z5 the longest and with 2 pairs of circular pores. Dorsal membrane with 3 pairs of platelets between podonotum and opithonotum, of which the anterior pair four times as big as other platelets. Seven pairs of scimitar-like setae arise free around dorsal shields (Fig. 9a). Ventrum with 7 pairs of simple setae and one pair of lyriform pores arise posterior to setae St1. Anal shield pear-shaped with postanal setae longer than adanals. Peritreme present, short and extends ventrally to the level of coxae III. Legs I-IV measure 418.80, 288.56, 269.68 and 397.92 μm, respectively (Fig. 9b).
Deutonymph: Hypostome as that of protonymph. Dorsal shield entire (497.20 μm long and 336.26 μm wide) but with two lateral grooves at the same level of setae J1 and with a complete number of setae as that of female. Setae j1 lanceolate while the other dorsal setae scimitar-like. Eight pairs of pores arise also on dorsal shield of which a pair of a crescent-shaped arises between j1 and j2 and another pair beside S5 (Fig. 10a). Tritosternum as that of protonymph. Peritreme well developed, extends anterodorsally to the level between setae z1 and s2.
| Fig. 10(a-b): | Cosmolaelaps qassimensis sp. nov., Deutonymph, (a) Dorsal shield and (b) Ventrum |
| Table 1: | Hypostome and its difference with other species |
Ventrum smooth, with 12 pair of simple setae and 2 pairs of lyriform pores and a pair of oval ones arise between coxae III and IV. Anal shield pear-shaped with postanal setae longer than adanals. Metapodal shield present arise posteriorly to coxae IV. Setae J5 scimitar-like (Fig. 10b). Legs I-IV measure 494.56, 354.32, 354.20 and 535.84 μm, respectively.
Notes: This species is considered a new and stands nearly to Hypoaspis (Cosmolaelaps) chianensis (Gu, 1990) and Hypoaspis (Cosmolaelaps) hrydi (Samsinak, 1961) but it can be separated by having the following differences (Table 1).
Materials examined: Holotype female and paratypes of 14 females and 8 males were collected from soil sample surrounding root system of date palm trees, Melida district, Buraydah West, Saudi Arabia on 12/9/2012. After that, an adult female was coupled with a male from a pure culture of C. qassimensis sp. nov. and provided with T. putrescentiae as food and kept at 26±1 and 65±5% RH for their whole life span.
Ethomology: The name qassimensis refers to the district from which the specimens were collected.
DISCUSSION
The present results showed that there were no significant differences between the average total number of C. qassimensis sp. nov., which was collected in May, July, August and October. That may be due to different environmental factors such as temperature, irrigation and associated soil fauna. Also, availability of food sources such as prey mites, insects and nematodes may have a considerable effect of survival and natural increase of C. qassimensis. Similar results were obtained by several authors who noticed that species of Cosmolaelaps as well as Hypoaspis can feed on different foods such as eggs and larvae of housefly Musca domestica L., vinegar fly, Drosphila melanogaster Morgan (Sherif and Afifi, 1980); mushroom sciarid fly, Lycoriella solani Winnertz (Enkegaard et al., 1997); springtail Folsomia fimetaria L. (Baatrup et al., 2005); egg masses of root-knot nematode M. javanica and citrus nematode Tylenchulus semipentrans (Cobb) and acarid mite Caloglyphus rodreguezi Samsinak (Al-Rehiayani and Fouly, 2005); springtails F. candida Willem and F. fimetaria L.; T. putrescentiae (Schrank) (Freira and de Moraes, 2007); acarid mite C. michaeli Oudemans and an oligochaeta worm Enchytraeus cryticus (Salmane and Brumelis, 2008).
On the other hand, the classification of laelapid mites is still confusing where the diagnostic differences between their genera and subgenera are still not clearly defined. Many acarologists have used different concepts for genera and subgenera especially predatory laelapid mite species belonging to the genus Hypoaspis Canestrini, 1884. Gu (1990) described C. chianensis as a new species and mentioned that it is similar to C. hrydi Samsinak (1961). Ma (2006) stated that as a result of the taxonomic confusion in the genus Hypoaspis and its subgenera, several species have been described in different countries with different names and sometimes a single species has, therefore, synonyms. Therefore, he found that H. (C.) shenyangensis (Bei et al., 2003) is considered a synonym to H. (C.) hrydi Samsinak (1961). H. (C.) hefeiensis (Xu and Liang, 1996) is also a synonym to H. (C.) chianensis (Gu, 1990). Joharchi and Halliday (2011) and Joharchi et al. (2012) stated that the existing classification of these taxa has been developed mainly using European fauna.
Therefore, a stable classification will not be possible until more taxa are described from different parts of other continents and from a wide range of host associations. Recently, Moreira et al. (2014) updated the characterisation of Cosmolaelaps because they found it was poorly described in its original description as well as in subsequent publications. They discussed the synonymy of Cosmolaelaps species and described more five new species from Brazil. Surely, the incomplete description of many Cosmolaelaps species makes it difficult to be subgroups. It is more difficult for scientists to do such studies without previous complete published data in some countries such as Saudi Arabia.
ACKNOWLEDGEMENT
This reasearch article is a part of the grant BC-L-05, entitled “Survey, identification, rearing and release of predaceous mites in Qassim, Saudi Arabia”. The project is supported by the Promising Research Centre in Biological Control and Agricultural Information (BCARC), Qassim University. Authors also wish to express their deep appreciation to Dr. Bruce Halliday, CSIRO Ecosystem Science, GPO Canberra, Australia for his assistance, providing numerous supplementary and useful publications and correction the illustrations.