Coastal oribatid mites (Acari) from New Zealand: new morphological, ecological, and developmental data

ABSTRACT Three species of oribatid mites associated with tidal rocks and mangroves were collected on Waiheke Island, Hauraki Gulf, New Zealand. One of the species was a yet undescribed member of the genus Indopacifica, collected in algae growing on roots of green button mangrove Conocarpus erectus. Here, we provide a description of Indopacifica impedimenta sp. n, including its juvenile stages, and discuss its distribution and differences from congenerics. The second species collected was Fortuynia elamellata, which was found in algae growing on intertidal rocks. Here, we provide supplementary morphological data on adult and juvenile stages and discuss their distribution and ecology. The third species found was Sellnickia caudata, collected from the same mangrove as Indopacifica impedimenta n. sp. However, S. caudata occurred only on leaves and twigs of the mangrove plants, which are not regularly flooded. We provide supplementary morphological data and SEM images of adults and a description of juvenile stages for this species. We also discuss the family placement of Sellnickia and provide barcode sequences for all species studied herein. http://www.zoobank.org/urn:lsid:zoobank.org:pub:8D74FD5A-27EE-48A9-8780-C1E6B1115629


Introduction
The soil fauna of New Zealand is unusual, diverse, and characterized by high levels of species endemism (e.g.Hammer and Wallwork 1979;Sirvid et al. 2010).Oribatid mites represent an important group of the soil fauna because they play roles in decomposition, nutrient cycling, and soil formation (e.g.Behan-Pelletier and Lindo 2022).Several hundreds of Oribatida species have been described in New Zealand earlier in the 20th century (e.g.Hammer 1966Hammer , 1967Hammer , 1968;;Luxton 1967).Since then, systematic work on Oribatida in New Zealand has continued with over 50 new species described in the recent decade (e.g.Olszanowski 1998;Liu and Zhang 2013;Colloff 2015;Ermilov et al. 2015Ermilov et al. , 2019;;Norton and Fuangarworn 2015;Ermilov andMinor 2015, 2019;Niedbała and Ermilov 2016).Currently, 465 species of oribatid mites are known to occur in New Zealand (Subías 2022).Even so, the knowledge about their diversity is still largely incomplete.
Most oribatid mites are terrestrial species living in soil and leaf litter, but some groups have also managed to colonize coastal environments, where they have adapted to daily tidal inundation and intertidal food resources (e.g.Pfingstl 2017Pfingstl , 2023)).Presently, members of two marine-associated oribatid mite families are known from the coasts of New Zealand, namely species of Podacaridae and Fortuyniidae.The Podacaridae prefer colder climates; therefore, they exclusively occur at the most southern shores of New Zealand, three species can be found on the South Island and seven other species are restricted to the subantarctic islands (Luxton 1990).The Fortuyniidae are adapted to warmer climates and only a single species, Fortuynia elamellata, could yet be found on coasts of Auckland (Luxton 1990).This species was described from New Zealand over fifty years ago (Luxton 1967) and apart from reports of two supposed subspecies, F. elamellata shibai (considered as F. shibai by Pfingstl et al. 2019) and F. e. micromorpha, from shores of Japan (Aoki 1974) and South Africa (Marshall and Pugh 2002), respectively, no further records have since been made of it.
During a short sampling trip to Waiheke Island in the Hauraki Gulf of New Zealand, which is 21.5 km off the east coast of Auckland, we collected three different oribatid mite species.One of the species is the above-mentioned F. elamellata, found in algae growing on intertidal rocks.The second species is a yet undescribed member of the genus Indopacifica, collected from algae growing on the roots of green button mangrove Conocarpus erectus.Indopacifica is a genus of typical intertidal oribatid mites and belongs to the family of Selenoribatidae.Members of this family occur on subtropical and tropical shores all over the world (e.g.Pfingstl 2017), but the record from Waiheke Island is the first record of this family from New Zealand.The other six species currently known in this genus are Indopacifica iohanna from the Philippines (Resch et al. 2019), I. mauritiana from Mauritius (Resch et al. 2019), I. pantai and I. parva from Thailand and Malaysia (Pfingstl et al. 2019), and I. taiyo and I. tyida from the southern Japanese Ryukyu islands (Pfingstl et al. 2021).
The third found species is Sellnickia caudata which was collected from the same mangrove as the new Indopacifica species.However, specimens of this species, which were making colonies, occurred only on higher parts of the mangrove plants, such as leaves and twigs, which are non-regularly flooded and thus do not represent a typical intertidal mite habitat.Michael (1908) described this species as Notaspis caudata from New Zealand.Later, Oudemans (1927) established the genus Sellnickia, by describing Sellnickia heveae from Sumatra, the second and still only other known species of this taxon.Grandjean (1958) transferred "caudata" to this genus and provided a complete description based on specimens from Australia.Finally, Hammer (1966) reported this species from New Zealand again and gave some additional depictions.Sellnickia caudata shows an interesting morphology, the rostrum shape is sexually dimorphic and both sexes possess an unusual porose pygidial tubercle.The function of these structures was discussed by some authors (Grandjean 1958;Norton and Alberti 1997), but without distinct conclusions.The ecology of this species is also interesting because specimens were all found above ground on leaves of plants (Grandjean 1958;Hammer 1966), indicating an arboreal lifestyle.In our observations, it appeared to to be feeding on plant tissue itself.To this day, however, nothing is confirmed about how these mites interact with the plant or if they can cause any damage to the plant.
The aims of the present paper are to describe the adults and immatures of the new species, provide additional morphological information on the already known species, give first descriptions of the juveniles of S. caudata, present first genetic data (barcodes), and update distribution data for all found species.

Material and methods
Samples of mangrove leaves were taken by hand and samples of littoral algae were scraped off rocks and mangrove roots with a knife or a small shovel.Afterwards, they were put in Berlese-Tullgren funnels for 12 to 24 hours to extract mites.Collected specimens were subsequently stored in ethanol (100%) for morphological and molecular genetic investigation.

Drawings and photographs
Preserved animals were embedded in Berlese mountant for microscopic investigation in transmitted light.Drawings were made with an Olympus BH-2 microscope equipped with a drawing attachment.These drawings were first scanned, then processed and digitized with the free open-source vector graphics editor Inkscape (https://inkscape.org).
For photographic documentation, specimens were air-dried and photographed with a Keyence VHX-7000 digital microscope using automated image stacking.For Scanning-Electron-Microscopic investigation, specimens were dehydrated and finally replaced in pentane, air dried, and then gold vapour-deposited.Scanning electron microscopic micrographs were taken by a JEOL JCM-6000PLUS SEM microscope.
Morphological terminology used in this paper follows that of Norton and Behan-Pelletier (2009).
Lateral aspect (Figure 1c).A broad lateral furrow reaching from dorsal to ventral sejugal scissure.Pedotectum I PtI present, round, small, pedotectum II absent.Lateral enantiophysis consisting of two opposite projections (s 1 , s 2 ); the anterior rounded, the posterior pointed and elongated.Discidium di developed as prominent conical bulge.
Legs (Figure 2).Monodactylous, long hook-like slender claw with one acute distinct proximoventral tooth and slight serration on proximal dorsal edge.Cerotegument granular.No porose areas detectable.Indistinct ventral carina on femur I and II.Lateral setae l of all genua scale-like, broadened, short, and blunt.Setation (first set of numbers, given in the order trochanter-femur-genu-tibiatarsus) and solenidia (second set of numbers, given in the order genu-tibia-tarsus): Leg I

Remarks
The new species can be distinguished from congeneric species by its minute notogastral setae (5-10 µm), all other species show distinctly longer setae (10-16 µm).There is also a slender triangular median longitudinal elevation on the prodorsum of the new species, such an elevation is lacking in Indopacifica iohanna and I. pantai and is conspicuously less developed in I. parva, I. mauritiana, I. taiyo and I. tyida.An obvious depression on epimeres I is present in all Indopacifica species but in none is it framed by distinct straight parallel ridges as shown in the new species.
Distribution.This species has yet only been found in a single location on Waiheke Island, New Zealand.A wider distribution along the warmer northern shorelines of the North Island should be considered.This is also the first record of a member of the family Selenoribatidae from New Zealand and represents the southernmost occurrence of this group.
Ecology.Specimens occurred in algae patches growing on mangrove roots; therefore, we can assume that this species prefers to dwell in mangrove habitats.Moreover, the claws of this species are slender and weakly curved, which is indicative for typical mangrove-dwelling oribatid mites (Pfingstl et al. 2020).Rostral, lamellar and interlamellar setae minute, exobothridial seta shaped like minute lamella.Sensillum clavate, distally spinose.Bothridium cup-like.Large centrodorsal plate bearing centrodorsal setae.Centrodorsal plate slightly convex, plateau-like; lateral and posterior inner borders of plate deepened like broad furrow.Large folds completely framing centrodorsal plate.Ventral furrows typical for selenoribatid juveniles.Legs, tarsus I with short knob-like famulus, no porose areas on femora detectable, genua with broadened scalelike lateral setae, claws with one sharp proximoventral tooth.
Gastronotic region.Fifteen pairs of notogastral setae, same positions and shapes as in protonymph, all of approximately the same length (10 µm).

Remarks
Presently, only juveniles of Indopacifica iohanna, I. taiyo and I. tyida are known (Resch et al. 2019;Pfingstl et al. 2021) and the immatures of the new species show an identical habitus, notogastral and ventral setation.Juvenile stages of I. iohanna lack a proximoventral tooth on their claws and thus can be easily distinguished from immatures of the new species.This proximoventral tooth, however, is present in nymphs of I. taiyo and I. tyida, but these show only two setae on tibia I whereas immatures of the new species show already three setae on this segment from the larva.Apart from these characters, there is no way to distinguish the juveniles of Indopacifica species.

Supplementary morphological data for Fortuynia elamellata
Family Fortuyniidae Hammen, 1963Genus Fortuynia Hammen, 1960 Fortuynia elamellata Luxton, 1967Luxton (1967) gave a very good and detailed description of the adult and juvenile stages of this species.Therefore, we only repeat the most important features and add very few morphological details that were not given in the original description.

Remarks
The specimens investigated herein match exactly the morphological description of Fortuynia elamellata specimens in Luxton (1967) and there is no doubt that we are dealing with the same species.The supposed subspecies F. elamellata shibai was described from Japan and shows differences in the length of notogastral seta da, in the position of the aggenital setae, the development of pedotectum I and the spur on trochanter III (Aoki 1974).A recent study (Pfingstl et al. 2019) concluded that these differences are of interspecific nature and that F. e. shibai represents a distinct species.We confirm the differences and agree that F. shibai should not be longer regarded as subspecies.Another suggested subspecies, namely F. elamellata micromorpha, was described from South African coasts (Marshall and Pugh 2002), and also diverges from the nominate species in the length of seta da, position of aggenital seta and size of pedotectum I, but additionally shows a striking difference in body size (380-404 µm in F. micromorpha versus 438-488 µm in F. elamellata).Altogether, this subspecies shows more differences to F. elamellata than F. shibai and thus its status as subspecies may also no longer be justified.A recent phylogeny of marine associated mites using morphological and molecular genetic data (Pfingstl et al. 2023) indicated a close relation of the above-mentioned taxa but did not render them as direct sister species or groups of a single clade.Moreover, the three "elamellata" species differ in the length of the 28S gene fragment and show different substitutions in at least one base pair, which strongly supports the distinctness of each species.

Ecology
Fortuynia elamellata specimens were all collected from intertidal rock habitats (Luxton 1967, present study) which indicates a preference for this type of environment.Furthermore, their claws are strongly curved and high (from dorsal to ventral edge), which indicates an adaptation to rocky tidal coastal environments (Pfingstl et al. 2020).
Distribution.Fortuynia elamellata has been reported from four different locations in New Zealand: (I) from the Three Kings Islands north of Auckland, (II) from the Bay of Islands in the northern part of Auckland region, (III) from the Takatu Peninsula in North Auckland (Luxton 1967(Luxton , 1990)), and (IV) from Waiheke Island close to the eastern shore of Auckland City (present study).All these occurrences are restricted to the northern parts of the North Island where warmer seawater temperatures prevail.Fortuyniid mites are known to be adapted to warmer climates (e.g.Pfingstl et al. 2021); therefore, it makes sense that F. elamellata may be restricted to the warm temperate regions of New Zealand.Although supposed subspecies of F. elamellata were found on shores of South Africa and Japan (Aoki 1974;Marshall and Pugh 2002;Pfingstl et al. 2021), the nominate species has not been found yet outside of New Zealand and thus may represent a strictly endemic species.
Juvenile stages.Apheredermous, dark brown in colour (similar to adults).Integument plicate and soft except more sclerotized centrodorsal plate.Pattern of plication and system of tracheal pores in folds typical for the genus.Prodorsum triangular, hysterosoma oval in dorsal view.Bothridium small cup, sensillum with short stalk and smooth clavate head.Interlamellar (in) and exobothridial (ex) seta already vestigial.In larva, all notogastral setae faintly serrated, in following stages only setae c 1 , c 2 and da with faint serration.Bases of notogastral setae surrounded by small pores.

Remarks
Our specimens of F. elamellata juveniles conform with the characteristics given by Luxton (1967).When comparing the juveniles of F. elamellata to immatures of the former supposed subspecies F. shibai (Pfingstl et al. 2021), they look very similar at first glance.The habitus, developmental setal formulas and the size range of each stage are identical.But the sizes and shape of nearly all notogastral setae are significantly different.In juveniles of F. shibai most notogastral setae (c 1-3 , da, dm, la, lm, h 2 ) are spinose and long, whereas in F. elamellata immatures all notogastral setae are relatively short (only a third of the length of the setae in F. shibai) and only the setae c 1-2 , da, dm are spinose; the rest are setiform.Juveniles of F. elamellata differ in the same way from immatures of the supposed subspecies F. e. micromorpha (Hugo-Coetzee et al. 2022) but the latter are ca.50 µm smaller in each stage and thus easily distinguishable.

Supplementary morphological data for Sellnickia caudata
Family Sellnickiidae Balogh and Balogh, 1984 Genus Sellnickia Oudemans, 1927 Sellnickia caudata (Michael, 1809) (Notaspis) Grandjean (1958) provided a very detailed and comprehensive re-description of the adults of this species.Herein, we only repeat and complement the most important features Integument.Colour dark brown.Cuticle smooth, except for gastronotic area showing faint foveate pattern (Figure 7a,e).Cerotegument absent, except for thin finely granular layer covering lateral area between bothridium and leg acetabula (Figure 7b,c).7c and 8a,c).Rounded in dorsal view; striking sexual dimorphism present, females with median rectangular rostral lobe, not seen in dorsal view, males also with median rectangular rostral lobe but lateral parts of this structure are strongly notched resulting in a frontal orientation of the lobe, which is then very well visible in dorsal view (Figure 8c).Rostral seta (ro) long (ca.80 µm), setiform and slightly ciliate, lamellar (le) and interlamellar seta (in) very long (150-165 µm), robust setiform and strongly ciliate.Exobothridial seta (ex) shorter (ca.75 µm) but also robust and strongly ciliate.Prominent lamellar ridge running from bothridium to the base of lamellar seta, nearly straight in dorsal view, curved in lateral view (Figure 7c).Tutorium (tu) developed as cuticular enfolding with sharp edge reaching from anterior of bothridium to insertion of rostral seta (Figure 7c).Sensillum short with slender stalk and large globular head covered by minute barbs.

Prodorsum (Figures
Notogastral region.Circular in dorsal view, with conspicuous large caudal protuberance (ca.50 µm) at the posterior end (Figures 7a and 8).Protuberance with median porose area at its terminal part; no difference in this structure between male and female.Dorsosejugal scissure medially interrupted.Two pairs of small inconspicuous ridges in humeral area.Ten pairs of minute notogastral setae (c 2 , la, lm, lp, h 1-3 , p 1-3 ), seta p 1 located on caudal protuberance (Figures 7d and 8a,c), seta p 2-3 only visible in lateral view.Octotaxic system consisting of large elliptical or round porose areas.Porose area Aa largest near vestige la, A1, A2 and A3 slightly smaller, all located on posterior half of notogaster (Figures 7e,f and 8a,c).Orifice of opisthonotal gland gla circular and laterad of seta lp.
Legs (Figure 10).Heterotridactylous, median claw strongest, lateral claws slightly weaker and with distal ventral indentation.All claws borne on an elongated slender pretarsal stalk, whereas stalk of tarsus I is slightly shorter than that of other legs.Cerotegument finely granular.Large porose areas on paraxial aspect of all femora and elongated porose areas on ventral side of each tarsus and tibia.A small dorsal porose area on tarsus I and II surrounding the base of solenidia.Tibia and tarsi elongated whereas in posterior legs they are relatively longer.Solenidia φ 1-2 of tibia I borne on small apophysis.Setae (u) on tarsus I remarkably pectinate ventrally, the same applies to setae (p) and (u) on all other tarsi (Figure 7g,h).Leg setation and solenidia: Grandjean (1958) provided the most detailed description for Sellnickia caudata and although his specimens originated from Queensland, Australia, the specimens from New Zealand investigated herein exactly match their morphology.We could not find any deviating characters.The second known species of this genus, Sellnickia heveae (Oudemans 1927), was synonymized with S. caudata by Subías (2022) based on their almost identical appearance.However, Oudemans (1927) noted that his species shows a thick, lanceolate and unilaterally ciliate palptibial seta unlike that of S. caudata which is typically setiform.This difference was confirmed by Grandjean (1958) and thus the supposed synonymy should be discarded (Behan-Pelletier 2015).Sellnickia heveae also possesses the characteristic pygidial protuberance and Oudemans (1927) hypothesized that it consists of a sticky material that allows the mites to glue themselves to the leaves when strong winds blow.Grandjean (1958) clearly contradicts that, stating that the pygidial tubercle rather secretes a typical cerotegument layer instead of a sticky substance.Observations in the field are clearly needed to answer if the protuberance is involved in attachment or in some kind of pheromonal communication, or in something else.

Remarks
The sexual dimorphism of rostral lobes found in Sellnickia caudata is unusual and the function is yet unknown.Norton and Alberti (1997) stated that the male lobe has got the right size and shape to fit over the pygidial tubercle of the female, and thus males could possibly "nuzzle" this protuberance.In that case, the question remains why males show the exact same pygidial tubercle with a probable secretory function.Sexually dimorphic rostral structures are known to occur in several other oribatid taxa, as for example in the genus Symbioribates where rostral setae are modified or in Nasozetes where there is a spatulate protuberance in the males (e.g.Behan-Pelletier 2015).These dimorphic structures in oripodoid and other mites may all be somehow involved in some kind of mating behaviour (e.g.Bayartogtokh et al. 2017Bayartogtokh et al. , 2022)).
The higher-level taxonomy of Sellnickia species shows some inconsistencies and needs clarification.The family Sellnickiidae, consisting of S. caudata and S. hevea, is accepted by Norton and Behan-Pelletier (2009) and Schatz et al. (2011), but Subías (2022) includes these two species in the family Oribatulidae.Grandjean (1958) was the first to discuss the family placement of Sellnickia and he argued that the genus shares many characters with Oribatulidae, as for example the elongated pretarsi, the notched lateral claws, or the tarsal porose area which is also present in Phauloppia and Lucoppia.At the same time, he admitted that there are certain characters in Sellnickia that are not present in Oribatulidae, e.g. the lack of centrodorsal setae, a sclerotized spermatopositor and a specifically shaped preanal organ, which could justify the erection of a separate family.However, Grandjean (1958) refrained from doing the latter and stated that a final decision should only be made when the juvenile morphology of Sellnickia is known in detail.Balogh and Balogh (1984) established the subfamily Sellnickiinae in Oribatulidae and listed the reduction of notogastral setae, the absence of the dorsosejugal suture, 5 to 6 pairs of genital setae and the adanal position of lyrifissure iad as diagnostic characters for this group.They also included the monotypic genus Grandjeania into this subfamily.Later, Norton and Behan-Pelletier (2009) were the first to mention the family name "Sellnickiidae" and they listed femur II with 5 setae, the caudal protuberance bearing porose area and seta p 1 , a complete circumpedal carina posterior to acetabulum IV and the possession of one solenidion on tarsus II as diagnostic traits for the family.The legs of Grandjeania are not known in detail but its notogaster exhibits two caudal protuberances that do not bear seta p 1 and the circumpedal carina is absent, at least according to the figures (Balogh 1963, p. 42); as a consequence, it was excluded from Sellnickiidae.Schatz et al. (2011) outlined the higher-lever classification of Oribatida and listed the Sellnickiidae as monogeneric family with two species, S. caudata and S. heveae and they mentioned Balogh and Balogh 1984 as family authors.Shortly after, Behan-Pelletier (2015) published a review on sexual dimorphism in oribatid mites which included details of Sellnickia caudata, but it was listed as a member of the family Oribatulidae in all associated tables.The recent world catalogue of oribatid mites (Subías 2022) conforms to that and includes Sellnickia in Oribatulidae, and accordingly the placement of this group of mites remains unclear.Based on the present data on adult and juvenile morphology (which follows in the next section), we think that Sellnickia should be placed in the separate family Sellnickiidae and not in Oribatulidae, although they are closely related to the latter group.The diagnostic familial characters given by Norton and Behan-Pelletier ( 2009) should be accepted whereas the presence of tarsal pulvilli in the immatures should be added to the diagnosis.The Sellnickiidae should only include the two Sellnickia species for now, but when more morphological details on Grandjeania and their juvenile morphology are reported in the future, the family might be adjusted in the sense of Balogh and Balogh (1984).

Ecology
Members of the genus Sellnickia have been exclusively found on leaves of trees and thus they are apparently arboreal.Specimens of S. heveae were collected from Hevea sp.tree leaves (Oudemans 1927), while individuals of S. caudata were collected from leaves of lemon trees (Grandjean 1958), from green leaves of an undetermined plant (Hammer 1966) and from twigs and leaves of green button mangrove C. erectus (present study).The occurrence on different species of plants indicates that the mites are not adapted to a specific type of plant.In the present study, we found high numbers of S. caudata specimens on nearly every investigated leaf, and they were observed to feed on the plant tissue and to form moulting aggregations on the underside of the leaves.Whether such strong infestations can cause harm to the plant is yet unknown, at least such cases have not been reported yet.

Distribution
Sellnickia caudata was originally described from Auckland, New Zealand (Michael 1908), but details about the exact collection site were not provided in the respective publication.This species was also collected in the Rotoehu State Forest in the Bay of Plenty (Hammer 1966) and now it was found on Waiheke Island in the Hauraki Gulf, New Zealand.Consequently, S. caudata may show a common distribution on the landmasses of north-eastern North Island.Outside New Zealand, there is a single report from Maryborough in Queensland (Grandjean 1958) pointing to a wider distribution in Australia as well.The second species, S. heveae was reported from Medan in Sumatra (Oudemans 1927).Presently, all members of the genus are only known from the Australasian region.

Description of juveniles
Common features of juvenile stages.Apheredermous.Bideficient; all opisthonotal setae associated with small porose excentrosclerites Figure 11a-c.Colour of prodorsum light brown, gastronotic region pale yellow.Integument soft, slightly plicate, except for stronger sclerotized prodorsum.Posterior edge of the prodorsum with a pair of lighter spots.All prodorsal setae long and barbed (Figure 11a).Bothridium small, cup-like.Sensillum short globose, surface of distal globe rough, covered with minute spines.A pair of small light spots adjacent to dorsosejugal scissure.Gastronotum oval in dorsal view, slightly convex in lateral view.Legs monodactylous with large lobe-like subunguinal pulvillus (Figure 11d).Porose areas present on femora, tibiae, and tarsi (difficult to observe).Seta d absent from genua and tibiae although respective solenidion is present.

Conspicuous changes during ontogeny.
The larva shows small porose excentrosclerites associated only with the notogastral setae.From the protonymph, numerous additional small, slightly invaginated porose sclerites appear on the gastronotum and these are not associated with other structures.The anterior notogastral setae c 1-2 , da, dm, la and lm are remarkably long, robust and ciliate in the larva, but in the protonymph they become small spiniform and smooth, and they keep this appearance throughout the subsequent ontogenetic development.

Remarks
Oudemans (1927) also found a tritonymph but gave very limited information on it in his work about S. heveae.He mainly mentions the ambulacrum which consists of a pretarsus equipped with a single claw and a conspicuous pulvillus ("carunkel").Immatures of S. caudata show the exact same feature on their legs.Tarsal pulvilli, only present in the juvenile stages, can also be found in Ametroproctus, Cymbaeremaeus (Behan-Pelletier 1987, 1988), Dendroeremaeus (Behan-Pelletier et al. 2005) and Megeremaeus (Behan-Pelletier 1990).Apart from the latter, all taxa are exclusively arboreal species; therefore, this morphological feature is clearly an adaption to this lifestyle.Most of these groups, including Sellnickia, are not related to each other, consequently juvenile adhesive pulvilli have evolved independently in these lineages (e.g.Pfingstl 2023).
Herein, we report the presence of opisthonotal excentrosclerites for the first time in the juveniles of Sellnickia, a feature that is characteristic for immatures of Oripodoidea (e.g.Norton and Behan-Pelletier 2009).
Common features of juvenile stages.Colour brown.Integument plicate and soft, except for centrodorsal plate.Whole cerotegument showing dense granulation.Prodorsum triangular, rostrum rounded.