Fauna of New Zealand 72: Micropterigidae (Insecta: Lepidoptera) -- Background and diversity
Gibbs, G W 2014. Fauna of New Zealand. 72, 127 pages.
(
ISSN 0111-5383 (print),
ISSN 1179-7193 (online)
;
no.
72.
ISBN 978-0-478-34759-3 (print),
ISBN 978-0-478-34760-9 (online)
).
Published 30 Jun 2014
ZooBank: http://zoobank.org/References/D6BC8C34-6D93-4EC7-BCB3-5670B2CFE744
DOI: 10.7931/J2/FNZ.72
Background to the study of New Zealand Micropterigidae
Francis Walker’s description of genus Sabatinca (Walker 1863) was based on Sabatinca incongruella (Fig. 3) which presumably was collected from the Nelson area (where it occurs today), although cited as: ‘Auckland, New Zealand, from Mr Oxley’s collection.’ T. R. Oxley, a professional photographer and the first resident lepidopteran collector based in New Zealand, lived in Nelson, but his specimens forwarded to Walker were mislabelled in BMNH as ‘Auckland’ (Dugdale 1988). Edward Meyrick, a classics master at Cathedral Grammar School, Christchurch, England, visited New Zealand between 1879 and 1886, making a large collection of New Zealand Lepidoptera, which included two micropterigid species: one from Hawke’s Bay, and another from Lake Wakatipu. He presented a paper at the 1st October 1885 meeting of the Philosophical Institute of Canterbury, in which he mentioned these as Palaeomicra n.g. chalcophanes (Fig. 18) and P. chrysargyra (Fig. 9) respectively. They were formally described the following year (1886) but it was not until 1912, back in England, that he realised Sabatinca had precedence over his genus Palaeomicra. Unfortunately, without critically examining the specimens, he wrongly assumed that Walker’s incongruella and his chalcophanes were the same insect, thereby establishing a source of confusion that persisted for nearly 40 years, influencing a number of important contributions by Tillyard (1919, 1922), Philpott (1923b, 1924c, 1927a, 1927c), and Hudson (1928), in which morphological descriptions of S. chalcophanes were incorrectly attributed to S. incongruella. Enlightenment finally became official after 93 years when Kristensen & Nielsen (1979: 140) examined the specimens in BMNH and reviewed the status of world genera.
Edward Meyrick established the genus Micropardalis (1912a), on the basis of wing venation, for the species he had described as Palaeomicra doroxena Meyrick, 1888 (Fig. 17). However, Alfred Philpott (1923–1927), who added six species to the fauna and contributed seven publications on micropterigid morphological topics, ignored Micropardalis and assigned all New Zealand species to Sabatinca Walker. Kristensen & Nielsen (1979: 140), in a generic catalogue of the family Micropterigidae followed this view, listing Palaeomicra Meyrick, 1886 and Micropardais Meyrick, 1912a, as synonyms of Sabatinca Walker, 1863. Kristensen (1984a: 169) later stated that the ‘very heterogeneous assemblage’ of New Zealand Micropterigidae ‘seem to be at most subgenerically distinct’, provided the ‘Australian species group’ of taxa (which included the New Zealand ‘Sabatinca’ zonodoxa (Fig. 23)) was separately recognised.
Meyrick’s intensive collecting and cataloguing of the New Zealand lepidopteran fauna became the foundation for G. V. Hudson’s contribution that was to follow in his fully illustrated volumes on moths in 1928 and 1939. Hudson had described one species (aurella (Fig. 16)) himself, later added another (aenea (Fig. 12)) and included the then current knowledge of the micropterigid fauna in both volumes, amounting to 19 species. John Dugdale compiled a catalogue of New Zealand Lepidoptera (1988) which forms the basis of our understanding today. He retained Micropardalis for doroxena and aurella but included all other species (including zonodoxa) within Sabatinca. Joel Minet (1985), on the other hand, when describing two new species of Sabatinca Walker from New Caledonia, discussed the overall status of the ‘Sabatinca-group’, reaching the conclusion that both Micropardalis and Palaeomicra should be elevated to the status of genus, in conjunction with a more focussed view of Sabatinca to include the New Caledonian taxa. The approach adopted here, although based on much the same reasoning, retains the overall scope of the genus Sabatinca for the dominant micropterigid genus of continental Zealandia and defines four species-groups to recognise the sub-clades revealed by molecular phylogenetic analysis (Gibbs & Lees 2014). Support for these subclades is not sufficient to warrant taxonomic status and, moreover, the splitting of the traditional Sabatinca generic epithet has the potential to jeopardize the usefulness of the Linnean binomen.
On a broader scale, phylogenetic analysis of the world-wide family Micropterigidae has progressed in recent years to the point where subdivision into five monophyletic lineages can be proposed with some confidence (Kobayashi et al. 2000; Gibbs et al. 2004; Gibbs 2010; Gibbs & Lees 2014). Although these lineages may ultimately be defined at the subfamily level, this revision of the New Zealand fauna does not take that step but uses the opportunity to highlight the fundamental morphological and biological distinctions between two of them: the Sabatinca lineage, and the ‘Australian-group’ lineage.
Diversity of Micropterigidae in New Zealand
The two well-defined clades (lineages) that occur in New Zealand, are defined as:
1. The ‘Australian clade’, distributed across the SW Pacific in Australia, New Caledonia, and New Zealand. This clade, currently containing eleven species in five genera (Gibbs 2010) and two undescribed species from Western Australia, is represented in New Zealand by the monotypic genus Zealandopterix Gibbs. Molecular phylogeny tends to assign this clade to the basal position in the family Micropterigidae but not with a high degree of confidence. It is characterised by the following synapomorphies: hindwing lacking all evidence for the presence of an R vein (Fig. 29); antennal scape only moderately swollen and barrel-shaped, either without or with just the barest hint of an indentation at its mid-length (Fig. 41); antennal flagellomeres with rugose micro-sculpturing and the sensory branches of the antennal ascoids arranged in a linear configuration, each ascoid arising comb-like from a circumferential groove around the flagellomere (Faucheux 2004) (Fig. 45). The larvae are unpigmented, roughly circular in cross-section with longitudinal furrows and 8 pairs of short abdominal prolegs (Fig. 82). They live in soil or rotten wood.
2. The ‘Sabatinca clade,’ previously regarded as confined to the Zealandia continental block (i.e., New Zealand and New Caledonia) (Gibbs & Lees 2014), has become ‘Australasian’ with the surprise discovery in 2007 of an isolated disjunct species in SW Australia (Gibbs, in prep). The lineage is species-rich, containing 18 New Zealand species but reaching its zenith in New Caledonia where more than three times that number is known (although only three species are described) (Gibbs & Lees 2014). It is characterised by: hindwing with R vein distinct in basal half (Fig. 25) or reduced to a ‘vestigial spur’ (Fig. 26, 27); antennal scape greatly swollen with a strong indentation on its mesal surface (Fig. 38–40); antennal flagellomeres with dense papillate micro-sculpturing and the sensory branches of the antennal ascoids arising from a circular or ovoid base, spreading like the spokes of a wheel (Fig. 42–44) (as in all micropterigid taxa (Faucheux 1997) apart from those in Australian clade above). The larvae are cryptically pigmented, hunchbacked, hexagonal in cross-section (Fig. 58, 59), lack abdominal prolegs and live amongst damp terrestrial periphyton, where they feed on liverworts (Fig. 249).
The lineage is presented here as three species groups (sub-clades), the incongruella-group shared with New Caledonia, and two groups endemic to New Zealand—a calliarcha-group and a chrysargyra-group; the latter subdivided further into an aurella-subgroup and a chalcophanes-subgroup.