LP Nymph Edit.mp4
A third trait of δ is its path, relative to other cuticular markers, particularly in the posteroventral region where segmental addition occurs. A permanent line δ always runs dorsal to ip in the larva, but in maintaining its relative position it usually comes to lie below ip in nymphs. Among Ameronothroidea, δ has this usual ontogeny in Aquanothrus and Chudalupia, but δ remains dorsal to ip in all juveniles in Paraquanothrus, Ameronothrus and Podacaridae (from Podacarus). There are few data for the other superfamilies: in Cymbaeremaeoidea, δ shifts below ip in nymphs of Scapheremaeus, but we have found no data for Licneremaeoidea.
LP Nymph edit.mp4
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Cymbaeremaeoidea retain h3 in all instars as do Licneremaeoidea, other than Lamellareidae, which lack it in the larvaa; Adhaesozetes has h3 in the larva but lacks p3 and c3 throughout ontogeny. Among Ameronothroidea h3 is lost from the larva in the fortuynioid families and one member of Aquanothrinae (P. spooneri); by contrast, Ameronothridae, Podacaridae and the other Aquanothrinae retain the plesiomorphic presence of larval h3. It seems likely that the regression of h3 in the fortuynioid families is a synapomorphy of the group (Behan-Pelletier 1997), while that of P. spooneri and Lamellareidae represent separate convergences. A unique derivation has been described for the podacarid subspecies Halozetes marinus devilliersi Engelbrecht, 1974, which apparently lacks la from the larva (as well as the protonymph)b.
a Martínez et al. (1995) noted that the larva of Tenuelamellarea argentinensis Martínez, Velis, Eguaras and Fernández, 1995 forms only two setae in the h-row and adds a third in the protonymph. However, their labeling of the larval setae (their Fig. 4C) seems incorrect, since the anterior and posterior of the two setae are respectively denoted as h1 and h2; these labels should be reversed.
Among Ameronothroidea, Ameronothrus and Chudalupia retain the tritonymphal setation (15 and 14 pairs, respectively). The same is true of the aquanothrine genus Paraquanothrus, but Aquanothrus varies: no losses (15 pairs), or unique loss patterns for 12 and 10 pairs. Podacaridae have 10-15, Selenoribatidae 13-15, and Fortuyniidae 14, all following the normal loss patterns. Tegeocranellidae have 10 or 12 pairs, but the complement of 12 is unique, including c2 while lacking da. Among Cymbaeremaeoidea, with some exceptions in the genus Scapheremaeus (see Colloff 2009), adults have 10-15 pairs, in the normal patterns. Scapheremaeus zephyrus Colloff, 2010 has nine pairs (lacking also p3) and S. longilamellatus Mahunka, 1985 appears to have seven pairs (lacking p2, p3 and la), but their tritonymphs are unknown so the timing of the losses is also unknown. Licneremaeoidea have a similar range, except we know none with 15 pairs. Micreremidae lose c3 (14 pairs) and Scutoverticidae have the same setation, at most, but may have as few as 10 in the normal patterns. Charassobatidae have 13 pairs and Passalozetidae and Dendroeremaeidae have 10, all in the normal patterns. Lamellareidae and some Adhaesozetidae (Phylleremus) lose five in the normal pattern, while Adhaesozetes loses none in the adult. Overall, the range of notogastral setations is similar among the three superfamilies, and we agree with Weigmann and Schulte (1977) that notogastral setations show too much regressive convergence to be highly informative as a phylogenetic character for the groups in question.
A less striking, but no less interesting exception is found in Paraquanothrus. While the epimeral ontogeny of P. grahami (Fig. 7B, D) is typical and virtually identical to that of A. montanus, that of P. spooneri (Fig. 13B, D) differs in an illuminating way. Epimere III of the larva bears a single, laterally inserted pair that are obvious homologues of 3b in P. grahami; the medial, soft cuticle is glabrous, with 3a absent as in Selenoribatidae. The second pair of epimere III setae are added medially in the protonymph, in precisely the same position as 3a in P. grahami. The simple and inescapable conclusion is that 3a is delayed one instar during the ontogeny of P. spooneri, relative to P. grahami.
Added to the loss (Selenoribatidae) or delay (Aquanothrinae) of seta 1c, these exceptions show that regressions and additions of epimeral setae, either in phylogenetic or ontogenetic time, can be independent of position. If pair 3a can be lost (Selenoribatidae) or delayed (P. spooneri) while 3b is unaffected, then the same should be possible on epimere IV. In our interpretation, epimere IV of P. spooneri has a setal ontogeny identical to that of epimere III, except that it is delayed one instar due to the protonymphal appearance of the epimere: pair 4b are protonymphal, 4a are deutonymphal. Similarly, we would denote the single epimere IV pair in Selenoribatidae, also protonymphal, as 4b.
a Wallwork (1981) wrote that Chudalupia meridionalis was similar to Ameronothrus in having iteral setae on all tarsi of adults, but this appears to be an error. We studied multiple adult and tritonymph topotypes of C. meridionalis and all possessed iterals on tarsi I-III while lacking them on tarsus IV.
a Pfingstl and Krisper (2011a; their Table 2) indicated that solenidion ω2 is added to tarsus II of Cymbaeremaeus cymba in the deutonymph, but this seems to be an error. In another paper of the same year (Pfingstl and Krisper 2011b; their Table 3) they indicated its absence, which is consistent with Grandjean (1964b) and our own studies of C. cymba specimens from Spain. 041b061a72