A New Species of Maindronia Bouvier, 1897 from Iran (Zygentoma: Maindroniidae)

A new species of the genus Maindronia Bouvier is described from a single female specimen collected in Iran. It appears close to M. mascatensis Bouvier but displays a distinct chaetotaxy compared to that illustrated by earlier authors. The morphology of the species is described in line with current standards including information on the notal trichobothria and the specialized sensilla of the antennae and palps.


Introduction
Bouvier (1897) described an unusual silverfish Maindronia mascatensis from six specimens collected by M. Maindron, near Muscat in Oman (Fig. 1), noting that the species shared characters of both the Nicoletiidae Lubbock, 1873 (lacking scales) and the Lepismatidae Latreille, 1802 (the presence of eyes). Escherich (1905) examined one of Bouvier's six specimens and expanded on the description, believing Maindronia represented a distinct and separate lineage to the other known families. Escherich's written description lacked much detail but he did provide four illustrations from which additional information can be derived, assuming they are accurate. Wygodzinsky (1940) described a second species Maindronia neotropicalis from Chile and Schremmer (1964) described a third, Maindronia beieri from Sudan. Wygodzinsky (1962) recorded Maindronia mascatensis from a locality in Afghanistan and commented that he was preparing a revision on the subfamily Maindroniinae Escherich, 1905, which unfortunately was never published. Here we describe a new species from a single female specimen collected in Iran. We have been unable to locate the six type specimens of M. mascatensis. One of these had been sent to Escherich (most of whose material has been lost), while the other five were supposedly in the Museum national d'Histoire naturelle, however these have not been found there (pers. comm. Markus Koch, 2018). They may have been transferred by Wygodzinsky to Buenos Aires or eventually to New York to facilitate his planned revision. While clear differences between the current specimen and the Escherich illustrations are present we have some doubt as to the accuracy of those illustrations. We also have little understanding of the intraspecific variability of species within this seldom collected family. Nevertheless, we have decided to describe this species as new, anticipating that the types of M. mascatensis if or when eventually found, will affirm this decision.

Materials and methods
The specimen was collected and placed into 100% ethanol. Locality co-ordinates were taken using a hand held Garmin eTrex®20 GPS. A mesothoracic leg was removed and retained in 100% ethanol and stored at 4°C to allow later DNA sequencing. The specimen was then transferred to 80% ethanol for about two months to allow it to soften. Pigment pattern was recorded and the specimen measured and prepared using the methods outlined in Smith (2013). Due to its large size, the dissected specimen was mounted on four slides (head and nota, legs and sterna, urotergites and urosternites I-VI, and the remainder) using Tendeiro medium; tissue was collected during dissection and stored in 100% ethanol for later DNA sequencing. Drawings were made with the aid of an Olympus CX31 binocular microscope fitted with a U-DA drawing attachment. One antenna and a cercus were not mounted on slides but sent to Córdoba for scanning electron microscopy. As previously reported with larger specimens of the Nicoletiidae (Smith et al., 2012;Molero et al., 2013) the Tendeiro medium had a distorting effect on many of the macrochaetae, although not enough to interfere with an interpretation of the chaetotaxy. Macrochaetae have been illustrated here without showing the change in surface texture visible on the slide mounted material.
The antenna and the cercus used for scanning electron microscopy were put through an ethanol dehydration series finished with hexamethyldisilazane (see Molero et al., 2013) and coated with gold with a sample coater BAL-TEC SCD-005. They were imaged using a microscope JEOL JSM 7800F.
Roman numerals are used to indicate abdominal segment number. The following abbreviations are also used: asl: above sea level (in metres); AMS: Australian Museum, Sydney; HW: head width (in millimetres); H+B: head and body length (in millimetres); L/W: length to width (ratio); PI, PII, PIII: legs of pro-, meso-and metathorax respectively; SEM: scanning electron micrograph; UCO: University of Córdoba.
Illustrations are fairly accurate for the macrochaetae and larger setae but the detail of the smaller setae and cilia is generally only indicative to give an idea of the length and type of bristle. Antennal segmentation uses the terminology introduced in Smith (2015) i.e. annulus for the smallest individual unit, interval for the collection of annuli forming a repeated pattern where the most distal annulus usually carries trichobothria and is referred to as a T-annulus. Nomenclature of the type of antennal sensilla follows that of Adel (1984). In previous work the first author used the term rosette when referring to the ring of chaetic sensilla (setae) around the circumference of each annulus of the antenna or terminal filaments. To avoid confusion with the rosette-like structures of Matushkina (2010), found on the antennae of many Zygentoma and Archaeognatha, this chaetotaxy will here be referred to as rings (of setae).  Schremmer, 1964 has only seven pairs of styli and the chaetotaxy appears to be less dense than in the new species.

Description
Appearance: Very large silverfish (Fig. 6), body elongate with parallel sides, dorsoventrally flattened, thorax only slightly wider than abdominal segment I, the following abdominal segments remain about the same width up until the fifth segment after which they slowly taper posteriorly to about 80% the width of the thorax. Eyes almost black. Scales absent but some areas of dark pigmentation as described below.
Body size: H+B length 16.5 mm, thorax width 2.3 mm; antennae incomplete 16.9 mm (a little longer than H+B) and terminal filaments incomplete 11.0 mm (⅔ H+B).
Cuticle and pigmentation: Surface of body, flagellum, legs and styli with tessellated appearance with scattered small setae (Fig. 7), cuticle without tessellated appearance on pedicel and scape, palps, tail filaments and ovipositor. Cuticular pigment blotchy, dark brown or deep purple. Pigment faded noticeably over several days after the specimen was mounted in Tendeiro medium. Antennae and terminal filaments without pigmentation. Head with pigment behind the eyes and along the lateral margins, with a weakly pigmented star-shaped region over much of the vertex, 3+3 distinct but small dark pigment patches occur on either side of the groove between the anterior bushes of macrochaetae and out towards the lateral margins as well as patches along the posterior margin of the vertex; a line of pigment on the dorsal surface of the mandibles; maxillary palp mostly without pigment except for the light pigmentation along the dorsal surface of the 3rd article; labial palp with line of purple pigment along the outer margin of the penultimate article. Pronotum with light pigment patchily over disk, becoming denser towards the anterolateral margins; mesoand meta-nota with very little pigment being only visible in the anterolateral region. Prosternum with conspicuous rectangular area of dark pigment posterior to the submedial combs of macrochaetae (except for between the combs), meso-and meta-sterna with oblique lines of pigment arising just posterior to the submedial combs angled towards the mid-line; pro-and mesosternum also with transverse line of dark pigment adjacent to the following segment. Coxa of all legs with blotchy purple pigment on inner anterior corners, trochanter without pigment, femora and tibia of all legs with pigment along the ventral line of strong macrochaetae and over much of dorsal surface. All urotergites pigmented in middle 50% with the pigment becoming darker towards the posterior margin of each urotergite, the degree of pigmentation of each segment is progressively stronger towards the posterior end; urotergite X darker especially along posterior margin, styli pigmented or more strongly sclerotized apically; ovipositor with light pigment along the mid-ventral surface of the anterior gonapophyses.
Macrochaetae: Smooth, apically bifid but bifurcations distinctly truncate even in smaller setae of antennae (Figs 2,8), some appear to be apically trifurcate while others have a double bifurcation (Fig. 3) and others quite flattened apically although still bifurcate; light brown in colour. Some carrot-shaped macrochaetae on legs ( Fig. 9). Many smaller setae or chaetic sensilla ( Fig. 2) also apically bifurcated but some, especially on the maxillary palp, almost pointed (slightly truncated apically under high magnification). Other setae are simple and lack bifurcation or apical truncation. Macrochaetae are present on the terminal filaments, the pedicel and scape but not on the flagellum of the antennae.
Head: Longer than wide, very flattened and prognathous with the antennal bases positioned well forward (Fig. 10); chaetotaxy well developed, anterolateral corners of frons with 1+1 bushes and a groove between them, the sides of which showed dark pigment when the specimen was in alcohol but which completely faded when slide mounted; behind these anterior groups there is a small gap before a short lateral group about two macrochaetae wide with 1+1 (or 1+2) isolated macrochaetae behind them (possibly homologous with the peri-antennal group of Lepismatidae) followed by a much longer gap to a small group of macrochaeta at the anterior corner of the eyes and another group on the margin behind the eyes and a stout carrot-shaped macrochaetae posterolaterally. Disc of head with scattered cilia. Clypeus difficult to see in slide mounted material but appears to have 1+1 proximal rows of strong macrochaetae, longer than those on the frons. Labrum with numerous long macrochaetae, two long thin setae and several cilia. Eyes dark, not prominent, composed of 12 ommatidia. -Antennae (Figs 4, 5, 11, 12) quite long and densely covered in apically bifurcate setae, scape longer than wide with subapical ring as well as four groups of strong setae in shorter (two setae) or longer (several setae) rows across the dorsal outer face, pedicel about as long as wide and only about half the length of the scape, with subapical ring of shorter strong setae and some very long macrochaetae. Limits between annuli of the flagellum are in some cases difficult to discern with a light microscope, but more evident with SEM, where they can be identified by the wrinkled integument ( Fig. 5). Six basal annuli of the flagellum each with one ring of setae and several trichobothria; in the first one, some trichobothria are inserted below the ring of setae showing the zone where the basal growth of the antennal flagellum originates. From the seventh annulus, each one has two rings of setae, but in the section between the 10th and the 30th some annuli have three rings, and in the apical part (more distal than the 100th annulus) the annuli bear only one ring of setae. When more than one ring appears in an annulus, they are closely positioned in the basal part of the antenna and more separated in the apical part. All basal annuli have trichobothria. The first annulus without these sensilla is the 14th. The number of annuli forming an interval increases towards the apex (three from annuli 26-28 and four from 44-47), to the point that most apical surviving intervals (Fig. 12) consist of 16 annuli. A high diversity of sensilla has been detected using the SEM; most of these are difficult to see with light microscopy, not only because of their small size, but also because of the similarity of some of these types with low magnification Records of the Australian Museum (2020) Vol. 72  and the fact that the high density of setae, all somewhat laid flat on the slide, makes examination of these structures difficult. Trichoid sensilla (cilia) are visible from the fifth annulus. A type of thin seta with bent base is present from the fourth annulus. At least four types of basiconic sensilla are present; three of them can be attributed to the types A, B and C described by Adel (1984). Some other types of sensilla are present, such as campaniform (usually associated with T-annuli) and dome-like sensilla that can considered as equivalent to coeloconic type. Rosette-like structures, like those described by Matushkina (2010), have also been observed in several annuli. The distribution pattern of these types of sensilla is very regular along the antenna. For example, a pair basiconic A -basiconic C is usually present in the same position of the antenna in each interval below the T-annulus (in the penultimate annulus of the interval when the interval consists of three or four annuli). -Mandibles (Figs 13,14) quite large with a well-developed incisor region but lacking a molar region, a line of 11 shorter and six longer apically bifurcate setae along the distal ventral   Fig. 15, with a very simple curved lacinia, which is a little longer than the slender galea, apex of galea without apical lobes, instead having a "chiselled-off" appearance like rodent teeth (on both left and right sides so probably not an injury), galea also with some stronger macrochaetae basally. Palp very long and slender, the apical article about 17 times longer than wide and similar in length to the penultimate article, basal article small with just a couple of bifurcated setae, second, third and fourth articles long with more numerous bifurcated setae and long cilia, especially around the distal end of each article, ultimate article quite thin, with three large papillae in the distal quarter, these resemble a large curved basiconic sensillum (type C of Adel, 1984) but with one or two apical papillae (Fig. 16). -Labium (Figs 17, 18) only very slightly longer than broad, postmentum very long with all setae confined to the distal half; prementum between palps with transverse row of cilia and setae, those laterally are bifurcated, paraglossae with oblique row of macrochaetae as well as a loose lateral bush of several macrochaetae and a row of weaker setae along the outer margin, apices of paraglossae and glossae with long cilia (Fig. 18); palps about the same length as labium, articles one to three with long bifurcated macrochaetae as illustrated (Fig. 18), apical article subrectangular, almost sausage-shaped and very wide being almost four times as wide as long, with a long anterior papilla of the aufgelöst type in the middle but becoming more compact towards each end, then something that resembles the 3+2 arrangement in many lepismatid genera although the two outer papillae in the more anterior row are also very long and the individual units of the papillae more compacted together; these papillae are fringed with a line of rod-like structures, the rest of the segment covered with numerous setae (some quite stout), no other specialized sensilla observed.
Thorax: Only slightly wider than head or abdomen, subparallel sides, the surface of all nota with scattered cilia, these being more numerous near the lateral margins. Pronotum (Fig. 19) only slightly wider than head (1.08) with slightly indented posterior margin; anterior margin without setal collar but with scattered cilia along the entire margin, lateral region of anterior margin with two groups of three macrochaetae on each side, lateral margin with a stout slightly carrot-shaped macrochaeta in the anterior corner, followed by a comb of three macrochaetae then an isolated trichobothrium slightly anterior of halfway (0.40 of total margin length along margin), followed by a comb of four or five macrochaetae, followed by another trichobothrium (0.62 along margin) followed by one or two presumably stout macrochaetae closer to the margin and an oblique comb of five macrochaetae, the trichobothria and the combs in the posterior half are much more distant from the margin than is usually observed in the Lepismatidae; posterior margin glabrous. -Mesonotum (Fig. 20) also with numerous scattered cilia over the surface (not illustrated) with the most anterior comb consisting of five macrochaetae, the following comb of four macrochaetae followed by a trichobothrium (0.44 along margin), and another trichobothrium (0.52 along margin), followed by a comb of five macrochaetae, then two (presumably) carrot-shaped macrochaetae on the margin at close to the level of the oblique posterior combs, these combs consist of six macrochaetae which become progressively larger posteriorly; the posterior margin with a very pronounced concavity medially. -Metanotum (Fig.  21) similar to mesonotum, with three combs on each side with five, four and five macrochaetae, each posterolateral corner with only one marginal macrochaeta, oblique posterior combs of five macrochaetae (Fig. 22), the trichobothria are located 0.64 and 0.82 along margin. Combs and trichobothria of all nota without associated setae, cilia or setulae although some of the scattered cilia of the disc may lie close to the combs or trichobothria. Presternum of prothorax ill-defined in slide material but glabrous (Fig. 23). -All thoracic sterna not free (Figs 23-25) with a large exposed area between the coxae, with 1+1 combs each of 6-10 macrochaetae adjacent to the precoxae.
Legs quite long (Figs 23-25), becoming progressively longer posteriorly with the tibia of PI only 0.64 the length of tibia of PIII and the tarsus of PI only half the length of the tarsus of PIII; tibia L/W ratio of legs PI 3.5, PII 3.3, PIII 4.1; tarsi L/W ratio PI 8.0, PII 8.6, PIII 13.7. -Precoxa of prothorax with a line of five macrochaetae, the most lateral being carrot-shaped as well as an isolated simple macrochaeta. -Coxae of all legs with several combs of up to ten macrochaetae along or near the lateral margin as well as some thicker isolated macrochaeta (three on PI, one on PIII), inner margin with three to six combs, the more proximal consisting of two combs close together, combs of up to thirteen macrochaetae as illustrated, with at least three strong and several smaller macrochaetae over the articulation with the trochanter. -Trochanter of all legs with two slender macrochaetae and one short carrot-shaped macrochaeta. -Femur with isolated stout macrochaetae along anterior margin proximally, then two or three similar macrochaetae about midway, distal quarter with two combs each of up to nine macrochaetae some of which are carrotshaped. Posterior margin of femur with up to three long carrot-shaped macrochaetae and a proximal comb. -Tibiae all with several stout carrot-shaped macrochaetae as well as mostly shorter, more slender, macrochaetae formed into numerous combs over the ventral face and anterior margin as illustrated, the carrot-shaped macrochaetae sometimes incorporated into the combs of thinner macrochaetae, apical spine with some small setae and a cilium. -Tarsus with four articles, the basal article on PI being about one third the length of the tarsus and two fifths on PIII, all tarsal articles with short carrot-shaped macrochaetae along the ventral surface and simple setae on the dorsal surface. -Pretarsus with long thick fairly straight outer claws that narrow and curve apically, medial empodial claw smooth and short.
Abdomen: Urotergite I (Fig. 26) with 4+4 combs of 2-5 macrochaetae each comb with and one or two cilia, as well as 1+1 carrot-shaped macrochaetae near the posterolateral corners. Urotergites II-III (Figs 27, 28) with 3+3 combs (missing the more anterolateral comb) as well as 1+1 carrot-shaped macrochaetae near the posterolateral corner; the redundant suture with the paratergites is vaguely visible on tergites IV-VIII (Fig. 29). Urotergites V-VIII with 4+4 combs as well as 1+1 carrot-shaped macrochaetae on the posterolateral corner. Urotergite IX (Fig. 30) with 3+3 posterior combs fairly close to the margin, the most lateral composed of two macrochaetae, the sublateral of 1-2 macrochaetae and the submedial of 1-2 macrochaetae, each comb with one or two cilia adjacent to the comb, when only one, this is usually lateral of the comb; medial region with irregular pigment -Urotergite X (Fig. 31) short, trapezoidal, with 1+1 submarginal combs of two macrochaetae on the apices and a single, carrot-shaped macrochaeta on the posterior margin adjacent to the combs, each comb associated with cilium lateral of the comb, the surface with a few scattered curved setulae, the medial area with pigment which is darker along the posterior margin, the posterior margin between the combs somewhat concave.
Urosternite I glabrous. Urosternite II (Fig. 32) with 1+1 submedial combs well anterior of the margin. Urosternites III with 3+3 combs (lacking the most lateral) (Fig. 33). Urosternites IV-VII (Figs 34-36) with 4+4 combs with two combs laterad of the styli and two mediad of the styli, the most lateral comb on II-VIII with 3-4 macrochaetae as well as a cilium laterad of the comb, the sublateral combs with 4-8 macrochaetae and rarely a cilium laterad of the comb, the lateral combs (mediad of the styli) with 7-12 thinner macrochaetae, the submedial combs with 8-10 thinner macrochaetae, often (but not always) with a small carrotshaped macrochaetae near the margin on either side of the stylet insertion and sometimes another laterad of the stylus. Coxites VIII in ♀ (Figs 37, 38) separated into two coxites each with three combs as well as five short carrot-shaped macrochaetae along the margins, one near the apex of the rounded outer process, two on either side of the rounded inner process and two more along the inner margin of the inner process; the lateral comb of 3-4 macrochaetae and a laterad cilium, the other two combs are at the base of the inner process, the comb adjacent to the stylus with 9-10 macrochaetae, the submedial combs of 7-8 macrochaetae.
Coxite IX in ♀ (Figs 37, 39) with a small lateral comb of three macrochaetae associated with a laterad cilium, and three combs quite close together on the internal process, the more lateral being slightly anterior to a smaller comb adjacent to the ovipositor and another smaller comb more posterior, apices of both inner and outer processes with one or two marginal, carrot-shaped macrochaetae.
Styli (Fig. 37) present in seven pairs i.e. on urosternites III-IX, those on IX being about 1½ times longer than those on VIII. All styli with terminal spines similar to that observed in the Nicoletiidae as well as several stout almost carrotshaped macrochaetae along the shaft of each stylus.
Ovipositor (Figs 37, 40) of primary type, moderately  I  2  3-5  2-3  3-4  ----II  -4  2  4  ---8  III  -2-3  2-3  3-4  -4 11-12 9-10 IV 4-5 2-3 2 4-5 3 4 11 8 V 2-3 3 2 3-4 3 6-7 11 10 VI 2 3-4 2 3-4 3-4 6-8 10-11 8-9 VII 2-3 3-5 2 4 3 6-7 11 9-10 VIII 2 2-3 2 3 3-4 -7-10 5 IX 2 1-2 -1-2 3 -9-10 7-8 long (1.1 times HW), surpassing the apices of the styli by about twice their length, with 28-29 divisions, each division especially those apically with small conical setae. Epiproct and paraprocts not strongly pigmented or sclerotized (Fig. 41), both appearing as very sharp processes over the base of the median dorsal appendage. -Cerci ( Fig.  41) incomplete, basal division short, about as long as wide, with three rings of setae, macrochaetae and trichobothria, pronounced joint to next division; second division about three times longer than wide, with six rings of strong macrochaetae as well as secondary rings of smaller setae and trichobothria between them; third division similar but with only four rings of strong macrochaetae, setae, long trichoid sensilla and trichobothria as well as about thirteen secondary rings, this division subdivided by faint suture a bit beyond half way; following three divisions only half as long with only two rings containing stronger macrochaetae, as well as several secondary rings. -Median dorsal appendage (Fig. 41) incomplete (>0.17 H+B) with basal division a little longer than wide with about four rings of simple or apically slightly bifurcate setae as well as strong slightly bifurcate carrot-shaped macrochaetae on each side of the more distal rings, the joint between this and the following segment very prominent appearing almost as a separate and slightly wider segment, the second division much longer (about four times longer than wide) with six rings of stronger setae including the lateral carrot-shaped macrochaetae as well as four rings of smaller apically-bifurcate setae between the more distal rings of larger setae and several long trichobothria, again with a prominent joint between this and the following division, the third division of similar length and chaetotaxy but with three subtle suture lines, dividing the division into four subunits, the basal and the most distal each with one ring of strong macrochaetae, the middle two each with two rings of stronger seta, all subunits with additional rings of smaller setae and many long trichobothria.
Male unknown.
Biology. The specimen was collected on tiles within a home.

Discussion
The Maindroniidae are not well known, with only four descriptive publications, the most recent by Schremmer in 1964, a time when the importance of trichobothria and specialized sensilla for lepismatid taxonomy was not recognised. Details of the chaetotaxy were also very cursory. This paper addresses some of the characters below but no doubt there is still much more to be learned.
The macrochaetae of Maindronia bashagardensis sp. nov. are referred to as smooth (although their surface structure is distinctly corrugated) and apically bifurcate and quite distinct from the barbed or pectinate macrochaetae seen in some lepismatid families. They are somewhat similar to the macrochaetae in Heterolepisma Escherich and Anisolepisma Paclt. Apically bifurcate macrochaetae appear throughout all known zygentoman families and are probably plesiomorphic as proposed by Mendes (1988).
The head has 1+1 bushes of macrochaetae in the anterolateral corners of the frons similar to those seen in several Lepismatidae. The clypeus appears small and with a few macrochaetae. The labrum is very wide and has numerous macrochaetae, more similar to the Lepismatidae than other families.
The mouthparts of the species are strikingly different to the other four extant families of the Zygentoma. The very prognathous and elongate head, the pincer-like laciniae and the apparent absence of a molar region of the mandibles, suggest a predatory behaviour (Koch, 2003). Schremmer (1964) reported on the extreme agility of M. beieri which suggests they have the speed and dexterity to pursue prey, although most Zygentoma are quite rapid in their escape behaviour. However, Zúñiga-Reinoso & Predel (2019) suggest otherwise due to the total absence of metameric prey in the hyperarid areas of the Atacama Desert from which numerous Maindronia specimens were collected.
The maxillary palps are extremely elongate, even more so than seen in troglobitic Nicoletiidae. The last segment has three sensilla in the same locations as seen on Heterolepismatinae Mendes, 1991, but the sensilla do not have multiple "arms" but just one or two apical papillae.
The last article of the labial palp of Maindronia bashagardensis sp. nov. is flat and extremely widened. The anterior margin has papillae in a 1+3+2 arrangement, the first distal papilla being very long, as are the two outer papillae in the next row. The individual units of the distal papilla are more widely spaced (aufgelöst) in the centre, but closer together in other parts. The other 3+2 papillae have the individual units more closely packed. The region occupied by all papillae is fringed with a row of stout rod-like structures of unknown function. While some similarity can be seen with arrangements in the Nicoletiidae (3+2+1) and many Lepismatidae (3+2) the arrangement in Maindronia is unique and offers little evidence of relationships. Six papillae in three lines may be the more ancestral condition.
The nota of Maindronia bashagardensis sp. nov. are not wide. The anterior margin of the pronotum lacks a setal collar but has a line of small cilia, similar to those over the rest of the surface of the nota. There are 2+2 groups each of three macrochaetae distally, which may perhaps be homologous with the isolated groups seen in a similar position of some Acrotelsatinae (e.g., Anisolepisma spp.).
All nota of Maindronia bashagardensis sp. nov. have submarginal combs, similar to many Lepismatidae. All nota also have two trichobothria on each side, suggesting a closer relationship to the Lepismatidae than the other families. The nota (and urotergites) uniquely have 1+1 (or 2) short posterolateral carrot-shaped macrochaetae.
The thoracic sterna of Maindronia bashagardensis sp. nov. are unlike any Lepismatidae, neither have the free sternum nor the raised medial mound between the coxae. The basic structure is more like that in the Nicoletiidae, Protrinemuridae Mendes, 2002 andTricholepidiidae Engel, 2006 and should probably be considered as plesiomorphic.
Antennal sensilla display a high diversity in the antennal flagellum of this specimen suggesting a close relationship between the Maindroniidae and Lepismatidae. Most of the types observed by Adel (1984) in Thermobia domestica (Packard, 1873) are present in Maindronia bashagardensis sp. nov. Common occurrences not only involve the types of sensilla, but even some aspects of their pattern of distribution, for example the constant association of a basiconic A sensillum with a basiconic C, as photographed by Adel (1984, page 201, fig. 20). However some sensorial structures, such as bent-base setae and some types of basiconic sensilla, appear to be exclusive to the Maindroniidae, showing a high degree of specialization. Sensilla in Nicoletiidae are less diverse, suggesting a more plesiomorphic position of this family respect to Maindroniidae. This agrees with the proposal of Koch (2003).
All urotergites of Maindronia bashagardensis sp. nov. have combs of macrochaetae but unlike those of the Lepismatidae, they are often quite remote from the margins. Combs are absent from the Nicoletiidae, Tricholepidiidae and Protrinemuridae.
Urotergite X is short, trapezoidal with a slightly concave posterior margin, the posterior apices each bearing a short comb of two macrochaetae. Short trapezoidal or weakly rounded shape is seen in most families of Zygentoma and is probably plesiomorphic.
Most urosternites have combs with only urosternite I being glabrous. The combs are however much more numerous than seen in the Lepismatidae and positioned over the disc not just near the posterior margin. The common ancestor of the Lepismatidae and Maindroniidae may have had several combs.
The ovipositor of the Maindroniidae is simple and similar to several Lepismatidae (e.g., Lepismatinae Latreille, 1802 and Heterolepismatinae). It lacks the field of small curved "hooks" seen in the ovipositor of the Nicoletiidae and is therefore probably more closely related to the Lepismatidae than the other families.
It appears that the Maindroniidae, while having thoracic sterna similar to the Nicoletiidae, share many more characters with the Lepismatidae and are probably a sister group. Their current disjunct distribution (Middle East and South America) supports the view that they are an ancient relic group.