The genus Arctorthezia Cockerell (Hemiptera, Ortheziidae) with the description of a new species

Abstract This paper describes a new species of Arctorthezia Cockerell (Hemiptera: Coccoidea: Ortheziidae) from the Palaearctic region. The specimens were extracted from forest litter in the collections of Muséum d’histoire Naturelle de Genève, Switzerland, using Berlese funnels. Three further species, Arctorthezia cataphracta (Olafsen), Arctorthezia occidentalis (Douglas) and Arctorthezia pseudoccidentalis Morrison, are redescribed and re-illustrated. The genus Arctorthezia now contains five species. An identification key, diagnostic illustrations, photographs of unmounted females and new locality records of the Arctorthezia species currently known are provided.


Introduction
Ensign scale insects (Hemiptera: Coccoidea: Ortheziidae) are considered to be one of the most ancient families of the Coccoidea (Koteja 1996, Vea andGrimaldi 2012) and are thought to be either 'ancestral' to all scale insects or a 'primitive', isolated branch of the grade of families, the archaeococcoids (Vea and Grimaldi 2012). Ensign scales are readily distinguished by (i) possessing distinctive, well-developed legs and antennae, (ii) having much of the body cloaked in bunches of white wax secretions (Vea and Grimaldi 2012). There are approximately 212 described species of Ortheziidae to date, classified in 21 genera (including four extinct genera) (Vea and Grimaldi 2012). Only a few species of ortheziids are serious pests; these include Insignorthezia insignis (Browne), the greenhouse ensign scale, and an invasive pest in Afro-tropical region, Praelongorthezia praelonga (Douglas), the citrus orthezia (Kondo et al. 2013). In Ortheziidae, two main groups of host plant specialization can be observed; the first group is composed of species that occur in leaf litter (feeding on roots and fungal mycelia), and on mosses and lichens; the second group feeds on vascular plants, including grasses, herbaceous and woody plants (Koteja 1996, Kozár 2004, Vea and Grimaldi 2012. The subfamily Ortheziinae is characterized by having the tibia and tarsus well separated, and 7-or 8-segmented antennae (Kozár 2004). Two tribes can be recognized in the subfamily, namely Arctortheziini Kozár and Ortheziini Amyot & Serville. The Arctortheziini includes species living in moist habitats -in litter, moss and feeding on the roots of different plants; whereas the Ortheziini includes species feeding on different kinds of plants (grasses, herbaceous, woody plants), mostly living in dry habitats. The monotypic tribe Arctortheziini includes only one genus, Arctorthezia Cockerell, which contains four living species: A. cataphracta (Olafsen), A. occidentalis (Douglas), A. pseudoccidentalis Morrison and A. vardziae Hadzibejli (Richard 1998) and one extinct species (Koteja and Zak-Ogaza 1988). Arctorthezia is characterized by (i) 9 pairs of dorsal wax plates in each marginal row, 8 pairs in the submedian band and 3 triangular or shield-shaped plates in the center of the thorax; (ii) 7-or 8-segmented antennae; (iii) 7 or 8 pairs of abdominal spiracles, and (iv) 3 or 4 spine rows within the ovisac band.
In the present paper, one new Arctorthezia species is described from the Palaearctic region (Switzerland); three species, namely A. cataphracta (Olafsen), A. occidentalis (Douglas), A. pseudoccidentalis Morrison, are redescribed and re-illustrated; an identification key and new additional locality records for the currently known Arctorthezia species are provided; and macromorphological characters are illustrated and discussed.

Material and methods
The specimens examined in this study were mostly from the scale insect collections of the Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences (PPI) and the Muséum d'histoire Naturelle de Genève (MHNG). Important material was processed from the Soil Zoology Collection of the Hungarian Natural History Museum, Budapest (HNMH), and part of the material was loaned from the United States National Entomological Collection, Washington (USNM). The material examined from Japan belongs to the collection of Tottori Prefectural Museum, Japan (TRPM).
Specimens were prepared for light microscopy using the slide-mounting method described by Kosztarab and Kozár (1988). The morphological terminology used follows Kozár (2004).
The holotype of the new species is deposited in the Muséum d'histoire Naturelle de Genève collection (MHNG), and the paratypes are shared between MHNG and PPI.
The digital images of unmounted females were made with a Canon Eos400D camera and an MBC-10 stereomicroscope, and focus-stacking was processed by Com-bineZP software (Hadley 2010).
Measurements and counts were taken from all available material, and the values are given as a range for each character.

Result and discussion
Genus Arctorthezia Cockerell, 1902 Orthezia ( Comments. Cockerell (1902) described Arctorthezia as a "section" of Orthezia. According to the International Code of Zoological Nomenclature, Article 10 (e) a "section" is deemed to be a subgeneric name when proposed for a species-group division of a genus. Thus, Cockerell is considered to be the author of Arctorthezia (Kozár 2004).
Description. Unmounted female. Live adult female with 9 pairs dorsal wax plates in each marginal row, 8 pairs in each submedian band, and 3 triangular or shieldshaped plates in centre of thorax. Ovisac parallel sided, short, about half length of body (Fig. 5).
Mounted female. Antenna 7 or 8 segmented, covered with strong spines; apical seta a blunted strong spine. Claw without denticle. Abdominal spiracles numbering 7 or 8 pairs, situated on margin of dorsum. Three triangular wax plates present on middorsum. Three or four rows of spines present within ovisac band.
Host plant. Found under mosses and stones on the roots of different plants, also reported from ant nests.
Distribution. The known species are distributed only in the Holarctic Region.

Key to adult females of species of Arctorthezia
Unfortunately the type material of A. vardziae was not available. For this reason we could not include this species in the key. In the original description, Hadzibejli (1963) only provided generic characters that refer to the genus description, so further studies are needed to clarify the species concept of A. vardziae. On the dorsum, with 9 circular discoidal pore plates present between marginal and submedian setal plates (Fig. 4)  Description. Live adult female: dorsum with 9 pairs dorsal wax plates in each marginal row, 8 pairs in each submedian band, and 3 triangular or shield-shaped plates in middle of thorax. Ovisac short, about half length of body (Fig. 5a).
Thoracic spiracle with wide band of disc pores inside atrium. Setae few, scattered in medial areas of thorax; several setae near anterior edge of ovisac band and associated with simple pores. Ovisac band wide, parallel side in the middle, with 4 spine rows within ovisac band. Multilocular pores with 4 loculi around perimeter, each loculus 4-5 mm in diameter and 1 loculus in central hub, 3 mm in diameter; pores present in 3 complete bands near posterior edges of each spine band, and scattered around vulva.
Dorsum: Wax plates covering entire dorsum; three triangular wax plates on middorsum, anteriormost 185-190 mm wide, 135-150 mm long; middle 250-270 mm wide, 150-160 mm long; posteriormost 260-280 mm wide, 170-180 mm long (Fig.  6b). Spines at margin of each wax plate each 22-24 mm long, apically capitate. A few setae present in marginal clusters near posterior edges of marginal wax plates; 3-6 setae present laterad of thoracic spiracle, longest seta 24 mm long; also present in very small numbers on other wax plates and in medial bare area. Multilocular pores generally with 4 loculi around perimeter and one loculus in central hub, sparsely present in wax plates. Abdominal spiracles numbering 8 pairs on the margin, last 3 pairs situated in posterior apical spine clusters. Anal ring 108-120 mm long, 108-120 wide, bearing 6 blunt anal ring setae, each 156-192 mm long.
Etymology. he species was named after the ancient name of its locus typicus, Switzerland (Helvetia).
Distribution. Switzerland. Ecology. Host plant: unknown, found in leaf litter and soil samples. Diagnosis. Arctorthezia helvetica sp. n. can be recognized by the following combination of characters: (i) 7-segmented antennae, (ii) dorsal triangle-shaped midthoracic setal plates hardly wider than long (iii) the proportion of simple pores and quadrilocular pores distal to vulva ca. 1:15, (iv) diamond-shape setal plate between mid-coxae on venter.
Comments. Arctorthezia helvetica sp. n. is closest to A. occidentalis in having 4 spine rows within the ovisac band and lacking circular pore clusters on the dorsum, but differs from A. occidentalis as follows (characters of A. occidentalis in brackets): (i) adult female body length less than 3 mm (adult female body length at least 3.5 mm); (ii) the fourth spine row within ovisac band weak (the fourth spine row within ovisac band strong); (iii) the proportion of simple pores to quadrilocular pores distal to vulva ca. 1:15 (the proportion of simple pores to quadrilocular pores distal to vulva ca. 1:6); (iv) dorsal triangle-shaped mid-thoracic setal plates hardly wider than long (dorsal triangleshaped mid-thoracic setal plates more than two times wider than long). Description. Live adult female: dorsum with 9 pairs dorsal wax plates in each marginal row, 8 pairs in each submedian band, and 3 small triangular or shield-shaped ones in middle of thorax. Ovisac parallel sided, short, about half length of body (Fig. 5b-c).
Venter: Labium 285-350 mm long, apparently one segmented. Stylet loop usually longer than labium. Legs well developed; leg measurements: coxa length: front 186-310 mm long, middle 192-300 mm, hind 224-330 mm; front trochanter+femur 623-800 mm long, middle 647-820 mm, hind 705-883 mm; front tibia+tarsus 423-991 mm long, middle 448-994 mm, hind 548-1165 mm; front claw 82-106 mm long, middle 96-108 mm, hind 97-120 mm; hind claw digitules each 26-39 mm. Legs each with rows of robust spine-like setae, with a fleshy sensory seta on hind tibia, trochanter with 4 placoid sensilla on each surface. Wax plates present on ventral areas of head and thorax, and wide marginal plate laterad of each thoracic spiracle; two wax plates present between mid-coxae, both in triangular shape, anterior one relatively small and longer than wide (Fig. 6c); with 3 spine rows within ovisac band. Thoracic spiracles each with wide band of disc pores inside atrium. Setae few, scattered in medial areas of thorax, with several setae near anterior edge of ovisac band and associated with simple pores. Ovisac band narrow, indented in the middle. Multilocular pores each with 4 loculi around perimeter and 1 loculus in central hub, 4-5 mm in diameter; present in 3 complete bands near posterior edge of each spine band, and scattered around vulva.
Dorsum: Wax plates cover entire dorsum; three triangular wax plates on mid-dorsum, anterior 40-130 mm wide, 60-195 mm long; middle 60-120 mm wide, 90-250 mm long; posterior 80-110 mm wide, 90-240 mm long, (Fig. 6d). Spines at margin of wax plate each 14-20 mm long, apically capitate. A few setae present in marginal clusters near posterior edges of marginal wax plates; with 3-6 setae laterad of thoracic spiracles, longest seta 17-20 mm long; also present in very small numbers on other wax plates and in medial bare area. Multilocular pores generally each with 4 loculi around perimeter, one loculus in central hub, sparsely present in wax plates. Abdominal spiracles numbering 8 pairs on the margin, last 3 situated in posterior apical spine clusters. Anal ring 120-132 mm long and 118-146 wide, bearing 6 blunt anal ring setae, each seta 136 mm long.

Arctorthezia pseudoccidentalis
Slide-mounted adult female (Fig. 4,. Body elongate oval, 4.015 mm long, 3.497 mm wide. Antenna 7 or 8 segmented. Measurements of antennal segments: 1 st 320-350, 2 nd 227-260, 3 rd 144-155, 4 th 113-124, 5 th 103, 6 th 93-103, 7 th 103, apical segment 191 mm long; apical spine of antenna 26 mm long, subapical seta absent; fleshy sensory seta near apical seta 18 mm long; all segments of antennae covered with very robust, spine-like setae, longest spine 11 mm long; first antennal segment with 2 spines on each side of segment. Eye with sub-parallel sides, tall, situated very close to first segment of antenna. Venter: Labium 391-402 mm long, apparently one segmented. Stylet loop usually longer than labium. Legs well developed; measurements of front coxa 247-310 mm long, middle 309-330 mm, hind 330-340 mm; front trochanter+femur 917 mm long, middle 958 mm, hind 1060-1088 mm; front tibia+tarsus not seen, middle 649 mm, hind 824-868 mm; front claw 1 not seen, middle 108 mm, hind 113 mm; hind claw digitules 23-26 mm; legs with rows of robust spine-like setae, without 2 fleshy sensory seta on tibia each 10 mm, trochanter with 4 placoid sensilla on each surface. Wax plates present on ventral areas of head and thorax, with wide marginal plate laterad of each thoracic spiracle; two wax plates present between mid-coxa in wide triangular shape, below one wide arch shape, with 4 spine rows within ovisac band (Fig.  6g). Thoracic spiracles with wide band of disc pores inside atrium. Setae few, scattered in medial areas of thorax, with several setae near anterior edge of ovisac band and associated with simple pores. Ovisac band wide. With four wide wax plate bands within Dorsum: Wax plates cover all dorsum; three shield-shaped setae plates on middorsum (first 390-540 mm in width, 290-400 mm in length; middle 540-710 mm in width, 330-460 mm in length; third 570-720 mm in width, 370-460 mm in length, Fig. 6h), 9 circular pores clusters, separating the dorsal and marginal wax plate bands. Spines at margin of wax plate 22-27 mm long, spines apically capitate. A few setae present in marginal clusters near posterior edges of marginal wax plates, with 3-6 setae laterad of thoracic spiracles, longest seta 40-50 mm long also present in very small numbers on other wax plates and in medial bare area. Multilocular pores generally with 4 loculi around perimeter, one loculus in central hub, sparsely present in wax plates. Abdominal spiracles 8 pairs on the margin, last 3 in posterior apical spine clusters. Anal ring 161 mm long and 127-138 wide with 6 anal ring blunted setae, each 259-264 mm long.
Concluding comment. Macromorphological characters of ortheziid species, such as the shape, number and arrangement of the wax plates of live (or dead) ensign scales have been useful for genus and in some cases for species identification (Kondo et al. 2013, Kozár 2004, Szita et al. 2010). These wax plates on the intact body (Fig. 5) do not always have the same appearance as the wax plates of the mounted female (Figs  1-4, 6). For example, the submedial dorsal wax plates of A. cataphracta are apparently in two parts on the intact body (Fig 5b), while on the mounted female there is only one undivided wax plate on each tergite in the same position (Fig. 2). In the case of Arctorthezia species both the usability and limitations of this method for separating species within the genus are clear; the medial wax plates and midcoxal wax plates can be useful characters for quick separation of species (Figs 5-6). Nevertheless, the correct identification of a species needs always to be confirmed by slide mounting.