Geometrinae (Holloway, 1996)

Young, Catherine J., 2006, Molecular relationships of the Australian Ennominae (Lepidoptera: Geometridae) and implications for the phylogeny of the Geometridae from molecular and morphological data, Zootaxa 1264 (1), pp. 1-147 : 1-147

Geometrinae

In the 28S D2 analysis the geometrines are represented by the Palaearctic Jodis putata and the Australian species Chlorocoma vertumnaria , Heliomystis electrica , Hypobapta percomptaria and the undescribed Sterictopsis sp .. The monophyly of the Geometrinae was unsupported by bootstrapping in the 28S D2 analysis. However the green geometrines J. putata and C. vertumnaria and the grey geometrines H. percomptaria and Sterictopsis sp. (Pseudoterpnini) were given low support as separate clades. H. electrica was placed within the Oenochrominae s. str. but without bootstrap support (Fig. 10). Contrastingly, the Geometrinae was well supported as a distinct clade in the combined molecular analysis ( H. percomptaria + C. vertumnaria ) (with a reduced data set) (Fig. 15) and in the morphological analysis ( C. vertumnaria + Sterictopsis ) (Fig. 16).

The Geometrinae , unlike the other geometrid subfamilies, is considered likely to be monophyletic ( Minet & Scoble 1999). A large quantity of the green pigment geoverdin occurs in most geometrines and this is considered as the most reliable apomorphy for the family even though small quantities exist in other moths ( Cook et al. 1994). The only pseudoterpnine included in the study by Cook et al. (1994), Pingasa venusta Warren also tested positively for high concentrations of geoverdin.

The structure of the tympanum is also considered to be relatively homogeneous within the subfamily. The diameter of each tympanum is about half the length of tergum A2 and they do not meet mesally. The ansa is usually narrow above the base, then widens and narrows again at the tip. However this description does not apply to all Pseudoterpnini or grey geometrines examined in this study. In Cyneoterpna alpina Goldfinch , C. wilsoni R. Felder & Rogenhofer , Heliomystis electrica , Hypobapta percomptaria , Sterictopsis sp. , S. divergens and S. inconsequens , the ansa is wide at the base and narrows to the tip, a shape more typical of the Oenochrominae s. l. ( Cook & Scoble 1992). Whereas in the pseudoterpnines Aelochroma turneri T. P. Lucas, Crypsiphona ocultaria Donovan , C. melanosema Meyrick , Epipristis oxycyma Meyrick , Hypodoxa emiliaria Guenée , H. muscosaria Guenée , Oenochlora imperialis Warren and Pingasa rubicunda Warren , together with the green geometrine C. vertumnaria , the shape of the ansa is typical of that of most geometrines (data not illustrated).

Other characters that define the Geometrinae are as follows. R is usually separate from Rs 1 and anastomoses with Sc for a short distance, R 2–5 is stalked and in the hindwing, M 2 usually arises closer to M 1 than to M 3. The frenulum is often reduced with a corresponding expansion of the humeral lobe. A secondary sexual characteristic in the male is two patches of deciduous spines on the sternum of A3. Large sclerotised socii are often present in the male genitalia often with a corresponding reduction in the size of the uncus ( Ferguson 1985). Cornuti are usually present as developments of the tubular sheath of the aedeagus and are not integral parts of the vesica ( Ferguson 1985; Pitkin 1996; Minet & Scoble 1999). In the green Geometrinae the eggs are often lozenge­shaped with planar walls and a sculpted chorion ( Salkeld 1983) but in the Pseudoterpnini examined here ( Young, 2006, in press) the sides of the eggs tend to be rounded and are usually relatively featureless (Fig. 23). The eggs of Sterictopsis argyrapsis are unusual in the columnar arrangement of the cells ( McFarland 1988). Larvae have pronouncedly bifid heads and a papillose or blistered integument ( Pitkin 1996). The tough, robust pupae are often variegated in colour and, unusually, form in a flimsy cocoon on the host plant or on the ground in debris but not in the soil ( Ferguson 1985; McFarland 1988).

Australia is the geographical centre of diversity of the Pseudoterpnini . This tribe of robust­bodied species is thought to be more primitive than the more slender­bodied greens. They inhabit the dry sclerophyll forests of southern Australia and feed mainly on Myrtaceae , including Eucalyptus ( Common 1993) . Common thought that the Pseudoterpnini may have evolved from tropical species such as Pingasa Moore and become adapted to the Australian flora. In the first instar larva of some stout­bodied genera, e.g. Hypobapta L. B. Prout , prolegs are present on A5 ( Common 1993) although this was not evident in H. percomptaria . Detailed redescriptions of these taxa are needed to elucidate the relationships within and between this group and the green geometrines. They were most recently reviewed by Goldfinch (1929).

Jodis putata and Chlorocoma vertumnaria

The sequence variation between these species for 28S D2 was 3.4% (Appendix 6). As discussed above, the Geometrinae are thought to be relatively secure as a monophyletic group. Jodis Hübner is a widespread genus with two western Palaearctic species and over 30 species in the Indo­Pacific and eastern Palaearctic ( Hausmann 2001). Chlorocoma Turner is also a large genus (25 spp.) with a disjunct distribution. Most species occur in Australia (21spp.), three are endemic to South Africa and one has been described from New Caledonia ( Scoble 1999). However, the Australian and South African species may not be congeneric (P.B. McQuillan pers. comm.). C. vertumnaria is a medium­sized, delicate moth with green forewings and hindwings fringed with pink cilia and a mid­dorsal yellow stripe extending from the first thoracic segment to the tip of the abdomen. This species occurs in southern Australia.

J. putata and C. vertumnaria have typical emerald morphology as described by Pitkin (1996):

—green wing scales; bipectinate antennae in males, rami of the antennae of C. vertumnaria scaled; female antennae filiform; wing venation Sc + R 1 not fused with Rs in hindwing, touching at a point close to proximal end of cell; M 2 arising from end of cell nearer M 1 than M 3; frenulum absent in J. putata , present but reduced in C. vertumnaria ; hair­pencil with groove present on hind­tibia; setose patches present on male A3 sternum; uncus slender, rod­like, narrow at base; socii extremely well­developed, large, long, sclerotised and erect; gnathos, a slender loop with an acute apex; valvae narrow (Fig. 25); signum absent in C. vertumnaria (Fig. 26), weak in J. putata .

Note: McGuffin (1981) stated that geometrine pectinations are unscaled; therefore the scaled pectinations of C. vertumnaria appear to be unusual. However Ferguson (1985) illustrated the antennae of the North American geometrine Synchlora aerata Fabricius with scaled rami. The antennae of the following Chlorocoma species are also scaled: C. cadmaria , C. carenaria , C. externa , C. tetraspila and an undescribed large Tasmanian endemic. Other Australian geometrine species possessing this attribute are: Chlorodes boisduvalaria Le Guillou , Eucyclodes buprestaria Guenée and Mixochroa gratiosata Guenée. Unscaled pectinations were found in Anisozyga insperata Walker , Heliomystis electrica , Hypobapta percomptaria , Pingasa cinerea and Sterictopsis sp. The occurrence of scaled rami in a reasonably wide range of genera may mean that it is more widespread in the family than originally thought. The absence of this attribute in Pseudoterpnini examined here is another distinction separating the two geometrine clades.

Differences

Setose area on male abdomen in J. putata a single patch, two patches in C. vertumnaria ; transtilla, larger and more prominent in C. vertumnaria (Fig. 25), bilobed; weak signum present in J. putata , absent in C. vertumnaria (Fig. 26).

Sterictopsis sp. and Hypobapta percomptaria

The adults of these species although supported as sister species by the 28S D2 data (sequence divergence = 8.7%) were dissimilar with regard to male genitalic characters (Figs 27 & 29) but had similar female genitalic characters (Figs 28 & 30) although Sterictopsis Warren , lacks the truncated ovipositor lobes typical of the Geometrinae ( Holloway 1996) . Sterictopis sp. is a small to medium­sized moth with greyish­brown elongate triangular forewings marked by transverse black stripes. The hindwings are a pale brown becoming darker distally. H. percomptaria belongs to a genus of five moderately large robust­bodied species. This species is common and widely distributed from Queensland in the north, to most of South­Eastern Australia. The forewings and hindwings are similarly patterned and are grey with strongly marked transverse bands. Sterictopsis sp. and H. percomptaria share the following morphological characters:

—bipectinate antennae; areole absent in the forewing; small juxta (Figs 27 & 29); curved aedeagus (Fig. 31 & 32); relatively long posterior apophyses; relatively short bursa copulatrix; absence of signa (Figs 28 & 30).

Sterictopsis sp. also shows some similarity to the other Pseudoterpnini included in this study. All three species examined, Sterictcopsis sp., H. percomptaria and H. electrica , have typical geometrine wing venation (see above). In Sterictopsis sp. and H. electrica the uncus is simple and well developed (Figs 29 & 33). However the socii in the former are very small and inconspicuous (Fig. 29) whereas in H. electrica they are more typically geometrine, being large and well­sclerotised but pendulous (Fig. 33) and therefore do not assume the role of the uncus in more typical upright forms such as in H. percomptaria (Fig. 27) that has a corresponding reduction in the uncus. Reduced socii correlated with well­developed unci are also present in the following pseudoterpnines: Aelochroma turneri, Pingasa rubicunda , Sterictopsis divergens and S. inconsequens .

The aedeagi of all three species are superficially similar; all are curved, with a long and narrow caecum extending anteriorly (Figs 31, 32, 34). The cornuti are not separate spines, a form common in other subfamilies, but are an integral part of the sclerotised wall as is typical of geometrine male genitalia ( Ferguson 1985). However the molecular data (28S D2) did not group the pseudoterpnines together (sequence divergence = 11.2%), instead linking H. electrica with the robust­bodied oenochromine Monoctenia falernaria (Fig. 10) (12.0%) but with low support.

There are also some morphological differences between Sterictopsis sp. and the other Pseudoterpnini . The rami originate mesally rather than basally on the antennal segments. This character appears to be variable within the Geometrinae , as Forbes (1948) stated that in this subfamily pectinations arise distal to the middle of the segments. Sterictopsis sp. has the typical reduced frenulum of most Geometrinae contrary to the well­developed frenulum, present, albeit with expanded humeral lobe, in the other two pseudoterpnines. Furthermore only Sterictopsis sp. has Rs + M 1 of the hind­wing distally stalked as in the green geometrine C. vertumnaria . Likewise only Sterictopsis sp. has the typical geometrine setal patches on the third abdominal segment and unlike the other two, lacks cristate hairs in the male genitalia and has a relatively small transtilla. The relatively small socii and well­developed uncus (Fig. 29), although not typically geometrine, are also present in the Nearctic tribe, Nemoriini ( Ferguson 1985; Pitkin 1996) and the distinctive Indoaustralian genus Dysphania Hübner (Holloway 1998) (see discussion below on Dysphania ).

The immature stages of Sterictopsis sp. and H. percomptaria are generally similar morphologically. The eggs of the three pseudoterpnines in this study are rather different from those of the slender­bodied green geometrines. Instead of the uniformly pill­box shape of the latter ( Salkeld 1983), these eggs have rounded edges and are narrow and elongate as in H. percomptaria (Fig. 23) to moderately broad bluntly ovoid in the other species. However like the eggs of the greens, the top profile of the egg is generally ellipsoid. The eggs are marked all over by flat to convex hexagonal cells. The aeropyles are inconspicuous, the openings small and, like those of the emeralds in this study, distributed around the rims of the eggs (Fig. 23). The eggs of these species bear some resemblance to the Australian robust­bodied nacophorines such as Paralaea Guest , Fisera Walker , Plesanemma McQuillan and Mnesampela Guest. The eggs of S. argyrapsis were photographed at low magnification by McFarland (1988) and are similar to those of other pseudoterpnines e.g. Hypobapta barnardi Goldfinch , H. percomptaria (Fig. 23) and Pingasa cinerea in general shape and form, however, unusually, the cells are arranged longitudinally.

The larvae of the two species share typical geometrine morphology of a pronouncedly bifid head capsule, blistered or papillose integument and elongated anal segments and prolegs (Fig. 35), and also similar chaetotaxy. In fact all geometrine larvae examined including the green geometrines Chlorocoma assimilis , C. haplochlora , C. vertumnaria , C. externa , C. melochrossa , Euloxia fugitivaria and E. meracula and the pseudoterpnines have SV2 missing but SV3 present on A1, and the full complement of SV setae for A3– A5. Ferguson (1985) incorrectly asserted that a diagnostic character for the Geometrinae was the absence of SV4 on A1 but presence of SV4 on A3–5. This error arose from the non­recognition of the sub­primary seta L4 and consequent incorrect labelling by Ferguson and several other authors (e.g. McGuffin 1964) of L3 as SV3, L4 as L3 and SV3 as SV4. Thus in the Geometrinae, SV 2 is generally absent on A1 and present on A3–5, a setal configuration also widespread in the Ennominae , Larentiinae and Sterrhinae ( McGuffin 1987) . However another apomorphy recorded by McGuffin (1964) and Ferguson (1985) was the unusually conspicuous presence of MD1 on the anterior abdominal segments in geometrines where dorsolateral projections are undeveloped and this attribute was noted here in all geometrines examined.

The crochet arrangement in H. percomptaria is very unusual and differs from S. argyrapsis and all other geometrines examined here. Crochets in the mature larvae of this species are completely absent from the A6 proleg and are arranged in a uniordinal completely interrupted mesoseries on A10. In most geometrids examined in this study (see also Appendices 2–5), crochets in the mature larvae were biordinal and in no other species was their absence recorded on A6. Other geometrids that have uniordinal crochets in the mature larvae in this study were the Australian larentiine Euphyia nr. severata, the Australian sterrhine Scopula perlata , the Australian nacophorine Corula geometroides and the Australian oenochromines s. l. Dichromodes sp. and Nearcha curtaria . The mature larvae of the outgroup noctuid species Proteuxoa cryphaea also has uniordinal crochets. S. argyrapsis also has its crochets arranged in a completely interrupted mesoseries, similar to H. percomptaria , and both of these species have a relatively large number of crochets per proleg (26–42). Whereas in the green genera examined, Chlorocoma and Euloxia Warren , the crochet arrangement is a biordinal incompletely interrupted mesoseries with relatively low crochet numbers (6–10); although this is most likely directly related to the size of the caterpillar. Despite these dissimilarities in the mature larvae, the crochet arrangements in the first instar larvae of the geometrines in this study are similar. The first instar larvae of Chlorocoma externa , C. vertumnaria , Euloxia fugitivaria , Hypobapta percomptaria and Pingasa cinerea all had crochets arranged as a uniordinal interrupted mesoseries.

The pupa of Sterictopsis is distinctive. Whereas most geometrine pupae are variegated in colour pattern, Sterictopsis shows the typically unicolorous pupa of Geometridae in general. This non­maculation was also recorded in the pseudoterpnines H. electrica , Lophothorax eremnopsis Turner and Cyneoterpna wilsoni by McFarland (1988); although some faint variegation is present in H. electrica . The cocoon of S. argyrapsis is also distinctive from those of other geometrines by being formed beneath the soil as is typical of most geometrids rather than being attached to the food plant or constructed in the leaf litter ( McFarland 1988). The pupae of all geometrines examined here and described by McFarland (1988) have eight cremastral setae, which is typical of the Geometrinae ( Ferguson 1985) . However the pseudoterpnines Crypsiphona ocultaria (25) and Lophothorax eremnopsis (>10) are distinctive in possessing multiple cremastral setae, a characteristic not yet recorded in green Geometrinae as far as I know. By contrast Hypobapta diffundens has a bifid cremaster making evident some intrageneric variability in this character. Multiple cremastral setae were also noted in the Australian nacophorine Fisera and this appears to be directly related to the number of setae on the larval anal plate (data not shown). It is not known whether this is also the case with the Pseudoterpnini .

The Pseudopternini, although sharing many typically geometrine characterisitics, are distinguished from their green relatives by greater morphological diversity in most life cycle stages. The eggs, although bearing some similarity to those of the greens, lack planar sides and are more ennomine­like in general shape. Larvae are generally typical and cannot be separated from the greens. However the crochet arrangement in H. percomptaria is unusual and this genus is further distinguished by the claimed presence of extra prolegs on A5 ( Common 1993), although this was not the case in percomptaria in this study. Male genitalia are also heterogeneous in structure and range from a generalised and rather atypical morphology in Sterictopsis with wide, simple valvae, well­developed uncus and gnathos and reduced socii to H. percomptaria that has contrastingly characteristic geometrine morphology with narrow, complex valvae, a reduced uncus and gnathos, and well­developed socii. The male genitalia of pseudoterpnines (e.g. H. electrica ) have varying permutations on these structures. Female genitalia are typically geometrine, although some taxa such as Sterictopsis lack the typical truncation of the ovipositor lobes. Pupae in some species e.g. Sterictopsis , are unicolorous in contrast to the usual variegated colouration typical of the Geometrinae and in this species, also, the cocoon is atypically formed beneath the soil. This diversity in morphology supports a possible sister relationship between the Pseudoterpnini with the green Geometrinae and this is also supported, to some extent, by the individual gene and combined molecular analysis. However no definitive synapomorphies can be elucidated, at this stage, for this assemblage of species and will have to await a more thorough revision of the group.