Paralamellobates, Bhaduri & Raychaudhuri, 1968

Behan-Pelletier, V. M., Li, D. & Fan, Q. H., 2016, Phylogenetic relationships of Paralamellobates: immature characters of P. misella (Berlese) place the genus in Punctoribatidae (Acari, Oribatida), Acarologia 56 (2), pp. 141-165 : 159-161

Relationships of Paralamellobates

Characters of Paralamellobates were compared with those of Lamellobates , and other poronotic Brachypylina including members of the Eremaeozetoidea , Licneremaeoidea , Phenopelopoidea ( Phenopelopidae ), Achipterioidea ( Achipteriidae , Tegoribatidae ), Oribatelloidea ( Oribatellidae ) Ceratozetoidea ( Chamobatidae , Punctoribatidae ), Oripodoidea, within a cladistic framework as much as possible. The table of relationships given in Behan-Pelletier (2001) is updated as Table 3, herein.

Prodorsum — Adult Paralamellobates share the apomorphic presence of a well-developed genal tooth with members of the Ceratozetoidea, Phenopelopoidea, Oribatellidae , Achipteriidae , and most Tegoribatidae (absent in Hypozetes ).

Opisthosoma — The opisthosomal integument of immature Paralamellobates misella is smooth, lacking plicae, porose regions and any indication of sclerites, including around the opening of the opisthonotal gland, found in many groups ( Figs 6 A-E). Among poronotic Brachypylina this type of opisthosoma is known only for some species of Chamobatidae ( Seniczak and Solhøy 1988, Seniczak and Żelazna 1994, Seniczak et al. 2014). In contrast, plicate nymphs are found in Eremaeozetoidea , Licneremaeoidea ( Adhaesozetidae , Dendroeremaeidae Licneremaeidae , Micreremidae , Passalozetidae , Scutoverticidae ); Achipterioidea ( Achipteriidae , Tegoribatidae ) and the Phenopelopoidea ( Phenopelopidae , Unduloribatidae ). Immatures of Oribatellidae are apopheredermous. Macrosclerites are found in nymphs of all Ceratozetoidea, other than some species of Chamobatidae , as noted above, and all Galumnoidea for which immatures are known ( Norton and Ermilov 2014). Porose microsclerites are an apomorphy of Oripodoidea ( Grandjean 1953). We interpret the absence of sclerotization in Paralamellobates as a loss, one that converges with the smooth opisthosomal integument in immatures of some non-poronotic taxa, e.g., larval Dorycranosus ( Seniczak and Seniczak 2010) (Gustavioidea) and Oppia ( Seniczak 1975) (Oppioidea) .

Setae h3 appears in the protonymph, rather than in the larva; the larva thus has 11 pairs of gastronotal setae. This delay in appearance of h3 is widespread in poronotic Brachypylina, including Hypozetes (Tegoribatidae) and members of the Licneremaeoidea , Phenopelopoidea and Achipterioidea (Behan-Pelletier 2001).

Nymphs of Paralamellobates have a bideficient setation, with absence of seta p 3 in addition to the usual seta f1. Adults of Paralamellobates have 9 pairs of notogastral setae, with c1, c3, d series, f1 and p3 absent, a number that probably also characterizes Lamellobates . Although Balogh and Mahunka (1977) noted 10 pairs of setae in L. molecula ( Berlese, 1916) (as L. botari ), they illustrated only 9 pairs. Similarly, Engelbrecht (1986) noted 10 pairs of setae for L. molecula (as L. angolensis Balogh, 1958 ), but only illustrated 9 pairs. In all illustrations of Paralamellobates and Lamellobates species the positions of the 9 pairs of notogastral setae are similar. Absence of seta p3 is rare among poronotic Brachypylina (Balogh & Balogh 1992), but has also been recorded for the punctoribatid Mycozetes oleariae Spain, 1968 , some genera of Oripodoidea (Balogh & Balogh 1992), the licneremaeoid Lamellareidae ( Coetzee 1987) and, along with loss of p2, for the phenopelopid Peloptulus ( Weigmann 2010) .

The length of some gastronotal setae in immature P. misella is striking ( Figs 4 , 5 , 6B ) and is equally striking in unpublished illustrations of immatures of P. bengalensis (N. Ramani, pers. comm.). Difference in length between lateral setae (la, lm, lp, h3, h2) and medial setae (da, dm, dp and c1 and c2) is much greater in the deutonymph and tritonymph (lateral setae ca. 2X length medial setae) than in the larva (length subequal) and protonymph (lateral setae ca. 1.3X length medial setae). Such difference in length (but not morphology) between lateral and medial gastronotal setae in immatures is rare, but is known in all immatures of the punctoribatid Mycobates acuspidatus Behan-Pelletier et al., 2001 . There also can be differences in gastronotal setal length among immatures of some of apopheredermous Oribatella species ( Behan-Pelletier 2011, Seniczak and Seniczak 2013). The relevance of this character state for relationships is unclear.

Immatures of Paralamellobates lack the humeral organ, which is almost universally present in immatures of Ceratozetoidea, Galumnoidea and Oribatellidae (Norton et al. 1997, Norton and Alberti 1997). It is absent in Eremaeozetoidea , Licneremaeoidea , Phenopelopoidea, Achipterioidea, and non-poronotic taxa.

Notogaster — Adult Paralamellobates have a posterior notogastral tectum which is medially divided with overlapping lobes. A posterior notogastral tectum is present in at least some members of all poronotic, brachypyline superfamilies, other than Phenopelopoidea, and the polarity of this character state is unresolved ( Norton & Behan-Pelletier 2009). However, the expression of this tectum, with unfused, medial lobes (overlapping or not) is rare, and is a character state which Paralamellobates shares with Lamellobates , the unplaced genus Sacculozetes , Adhaesozetidae (Licneremaeoidea) , Zetomotrichidae (Oripodoidea) , and Punctoribatidae (Ceratozetoidea) among poronotic Brachypylina (Behan-Pelletier 2001; Behan-Pelletier and Eamer 2008, Grandjean 1953; Walter and Behan-Pelletier 1993). The rarity of a divided notogastral tectum in Brachypylina and its possible origin was addressed by Grandjean (1955) and Behan-Pelletier (1988), but the adaptive value of a divided tectum is unclear.

Venter — A most distinctive character of adult Paralamellobates and Lamellobates is the reduction of adanal setation to 1 or 2 pairs. This reduced number is rare in poronotic Brachypylina (Balogh & Balogh 1992), though it is also found in Sacculozetes . Adult Paralamellobates have the postanal porose area on the ventral plate, a structure absent from the Eremaeozetoidea , Licneremaeoidea , Phenopelopoidea, and Achipteriidae . The postanal porose area is also found in Ceratozetoidea, Galumnoidea, Oribatellidae , and Tegoribatidae and its presence is considered apomorphic.

Octotaxic System — The octotaxic system in adult Paralamellobates and Lamellobates is composed of 4 pairs of saccules, but the structure of these is unique. They are dimorphic with Sa, S2 and S3 filiform, and S1 short and tubular ( Behan-Pelletier 1998). This dimorphism is a synapomorphy of these genera.

Gnathosoma — The mouthparts of Paralamellobates are similar to those of most members of Ceratozetoidea: a mental tectum is lacking, chelicerae are developed normally, eupathidium acm is fused along much of its length to the solenidion on the palp tarsus, and the axillary saccule of the infracapitulum is present. The latter character state is found in adults of some Licneremaeoidea , and all Ceratozetoidea, Phenopelopoidea, Galumnoidea, Oribatellidae , Tegoribatidae and is considered apomorphic; it is absent from Eremaeozetoidea , Oripodoidea and Achipteriidae .

Legs — Paralamellobates lack solenidion φ on tibia IV of the nymphs and adult. While its loss from the regressive protonymphal leg is general in oribatid mites, its loss from later instars is a rare apomorphy in the Brachypylina. For those with known ontogeny, it is expressed only in the phenopelopoid subfamily Phenopelopinae ( Eupelops and Peloptulus ) ( Grandjean 1964), and in Neoliodes theleproctus ( Hermann, 1804) (Neoliodidae) ( Grandjean 1964). Solenidion φ is present in all species of Tectoribates (Tegoribatidae) (Behan- Pelletier and Walter 2013), and in species of Tegoribates (new obsv. VBP), but is absent in Hypozetes (Tegoribatidae) , a possible loss.

Among Brachypylina where only the adult is known, solenidion φ is absent from tibia IV of adult Lamellobates , where leg setation is known, e.g., L. intermedius Nübel-Reidelbach & Woas 1992 , L. reticulatus Behan-Pelletier, 1998 , and from tibia IV of adult Sacculozetes filosus Behan-Pelletier and Ryabinin 1991 . Engelbrecht (1986) did not describe the leg setation for P. ceylanicus , but he illustrated an alveolus with no visible solenidion on tarsus IV in Lamellobates molecula (as L. angolensis ), and indicated its presence in the leg solenidial formula. Similarly, Behan-Pelletier and Ryabinin (1991) noted the alveolus for solenidion on tibia IV in Sacculozetes filosus . In P. misella there is neither solendion nor alveolus.

Immatures and adults of Paralamellobates lack seta d on genua I-III and all tibiae (DDC el, sensu Grandjean 1953). They share this apomorphic character state with all members of the Ceratozetoidea and some Eremaeozetoidea and Licneremaeoidea (Behan-Pelletier 2001, Norton and Behan- Pelletier 2009). In contrast, seta d is retained to the tritonymph in Tegoribatidae , to the tritonymph on tibia IV of Achipteriidae , and to the adult on tibia IV of Phenopelopinae . In Phenopelopinae seta d on tibia IV has no companion solenidion, whereas d is associated with the solenidion in Achipteriidae . Norton and Behan-Pelletier (1986) proposed that the unusual retention of d on tibia IV of the adult of Phenopelopinae may involve an atavistic reversal associated with the need for at least some sensory capacity in the dorsal area of tibia IV, but this argument is not supported by the absence of both seta and solenidion from tibia IV of adult Paralamellobates , Sacculozetes and Lamellobates , and the tegoribatid Hypozetes .

Solenidion ω 2 is absent from from tarsus II from all species of Paralamellobates and Lamellobates where leg setation has been described, e.g., P. striatus , Lamellobates molecula (as L. angolensis ) ( Engelbrecht 1986), L. reticulatus Behan-Pelletier, 1998 . Among poronotic Brachypylina, this solenidial absence is rare, but also is found in Mycobates parmeliae ( Michael, 1884) and M. beringianus Behan-Pelletier, 1994 of the ceratozetoid family Punctoribatidae ( Behan-Pelletier 1994) , and also in Micreremus brevipes ( Michael, 1888) of the licneremaeoid family Micreremidae ( Pfingstl and Krisper 2011) .

Figures

FIGURE 6: Paralamellobates misella (Berlese): A – Egg and larva photographed live among fungal hyphae in growth medium, surrounded by faecal pellets of adults; B – deutonymph photographed live, showing length of interlamellar seta, usually broken in preserved specimens; C – tritonymph, dorsal showing absence of sclerotization; D,E, Differential interference contrast microscope images of immatures: D – tritonymph, ventral, showing absence of sclerotization; E – larva, part of prodorsum, showing tubercle nature of cerotegument (arrow). Scale bars: A, B = 100, C, D =20, E = 30.

FIGURE 4: Paralamellobates misella (Berlese), larva, dorsal aspect, legs not illustrated. Scale bar = 50.

FIGURE 5: Paralamellobates misella (Berlese), tritonymph, dorsal aspect, legs not illustrated. Scale bar = 50.