Review of Australasian Chonocephalus Wandolleck (Diptera: Phoridae)

27 new species of Chonocephalus Wandolleck are described. C. tertius Schmitz is synonymised with C. secundus Schmitz. A key to males and a partial key to the females of the Australasian Regions species are provided.


Introduction
The tiny scuttle flies of the genus Chonocephalus Wandolleck are noted for their sexual dimorphism, with the females being flightless but the males being normally winged. Many species breed in ripe fruits, while some exploit other sources of fermenting detritus or plant material, and some are fungivores. The males transport females to suitable larval pabula during nuptial flights (Disney [7]).
Many casual collectors seem unaware of the sexual dimorphism in this genus and consequently have tended to collect only one sex. The naming of undescribed species on the basis of one sex only created taxonomic chaos. The growing list of undescribed males and females had become such that I am now naming undescribed males but assigning code numbers only to undescribed females not yet associated with their males. Such a policy runs the risk that we may describe as new some named species already known in the female sex only. As these are associated with their males, we will thereby create some synonyms. This is probably a smaller price to pay than a confusing proliferation of species (described from males alone) known by code numbers only alongside a smaller list of females known only by code letters. Museum collections abound in misidentified specimens and many species awaiting description. In order to provide the basis for moving forward, all named species in literature were reviewed and keys to the Nearctic and Palaearctic species were provided. Furthermore this revision of the 43 previously recognised species on the world list reduced this to 32 valid species, with the possibility that some only known in the female sex might be the missing females of some species only known in the male sex (Disney [10]). Subsequently six new species were added, one further synonym was proposed when the Afrotropical species were revised (Disney [11]) and another subsequently synonymised (Disney [13]). This was followed by revisions of the Neotropical species (Disney [12]) and Oriental species (Disney [14]).
The western boundary of the Australasian Region is debatable. Some authors (e.g. Lincoln et al. [16]) prefer Wallace's Line while others (e.g. Oosterbroek [17]) favour Weber's Line. The fact is that Wallacea, which is the region between these two, embraces elements of the faunas of both regions as well as elements peculiar to itself. An Afrotropical and Oriental group found in Wallacea but not beyond Weber's Line is the fungus growing termites. As there are many termitophilous Phoridae associated with these termites it has been considered sensible to arbitrarily opt for Weber's Line as the boundary between the two regions as far as Phoridae are concerned (Disney [8]). Consequently species from Sulawesi are covered by the review of Oriental species of Chonocephalus (Disney [14]).

Methods
The identification of members of this genus requires slide mounted specimens. Indeed the females can only be reliably identified by means of internal features of the abdomen (see below). The preferred mounting medium is the so called Berlese Fluid gum chloral medium, used with coverslips of 10 mm and 6 mm diameter (Disney [5] & [7]). Upton ([21]) has advised Review of Australasian Chonocephalus Wandolleck (Diptera: Phoridae) against use of this mountant, but some of his criticisms are based on a number of dubious assumptions and misapprehensions (Disney [9]).
For males, the recognition of the species depends primarily on the details of the hypopygium. These are best detached from the rest of the fly and mounted under a separate 6 mm coverslip with the underside uppermost. When several specimens are available then it is useful if some are mounted to display the left face of the hypopygium. Females are mounted whole with the dorsal face uppermost. When several specimens are available it is useful to detach the legs from at least one specimen and mount these under separate coverslips.
Some museum specimens had been mounted dry on pins. These have been remounted on slides following treatment in Barber's Fluid (see Disney [9]). However, some of the males in particular had suffered damage when they were glued to card points or placed in a drop of glue on the side of a pin. In particular the hypoppygium was sometimes fractured and its processes were sometimes broken off. This means that the illustration of some critical features has not always been possible.

Diagnosis
Male: Ocelli present. Wings with costa clearly exceeding half wing length, vein 3 unforked, base of vein 4 missing, vein 6 not deflected forwards in middle third, microsetae of rear margin about three times as long as distance between adjacent microsetae, and without axillary bristles. Hypopygium with short anal tube and at least one gonopod. Mid mesopleural ridge present and at least one and usually at least three small hairs near rear margin of mesopleuron. Tibiae lack near-dorsal longitudinal hair palisades and pre-apical isolated bristles.
Female:Ocelli absent. Wings and halteres absent. Abdominal tergites 1/2 to 7 well developed. Four supra-antennal bristles present. At least most of sternite 8 and all of S9 (furca) are internal, and the single spermatheca is typically lightly sclerotised. Tibiae lack near-dorsal longitudinal hair palisades and pre-apical isolated bristles.

Males
The recognition of species depends primarily on the details of the hypopygium, which is at first sight very complex. However, if one ignores the, often elaborate, penis complex (X), the details of the epandrium (E) and hypandrium (H) that are referred to in the key below are indicated in Fig. 1. This represents a generalised, stylized, hypopygium. While the anal tube (A) is seldom utilised in the recognition of species it is a useful point of reference. Any one of the labelled structures may be modified and may sometimes be very elaborate in form. In the inferred ground plan state the rear margin of the hypandrium bears four processes. These are the gonopods (G) and a pair of median lobes (L). In the plesiomorphic state the gonopods articulate with the dorsal face of the hypandrium, but more frequently they arise from it. One (usually the left) or both may be reduced or absent. The median lobes (L) may form a single bilobed structure or be reduced to a single lobe (which may be greatly elongated) or be lost altogether. Ventrally each side of the epandrium (E) typically bears an anterior process (AP) and a posterior process (PP). In some species the anterior processes (AP) may appear to be appendages (attaching to the inner face of the epandrium) rather than simple projections of the epandrium. A presumed true left surstylus or clasper is frequently present (C in Fig. 1) variably fused to the epandrium, and is sometimes elaborate. Occasionally it is fused to the bridge (B), which is sometimes present and probably represents sternite 10. The most anterior (lower) bristle of the left side of the epandrium is sometimes modified into a spine (S), which may be further modified.

Females
The morphology of the females has been discussed elsewhere (Disney [6], [10]). It was concluded that the first, long, abdominal tergite is a composite of T1 + T2 fused together, and that the last, also relatively long, fully developed tergite is T7 (Fig. 2). The microtrichia, lying between the hairs on these tergites (Fig. 93) are frequently reduced in size and consequently tend to be more densely packed and only discernible at higher magnifications. Otherwise the taxonomically useful features are mainly the form and size of the modified abdominal tergite (T8) and sternite 8 (S8), the internalised sternite 9 (furca) and the spermatheca. Typically the remnants of T9 are variably fused to the anterolateral apodemes of T10. These structures are most fully developed in C. blackithorum (Figs 3-4). The form and dimensions of sternite 8 have proved to be especially valuable taxonomically. This sternite has seemingly evolved from an isosceles triangular sternite whose anterior end continues internally as an anteriorly directed apodeme (Fig. 4). In many species the external sternite is greatly reduced or lost while the internal apodeme has increased in length. In some species a small sternite is retained as an externally visible projection. Tergite 8 is frequently reduced or seemingly absent. In the latter case it is present but only very lightly pigmented (e.g. Fig. 91).Its presence may be discerned in many such cases by locating a minute hair at each posterolateral corner. However, these hairs are sometimes absent. There can be some confusion between the furca and spermatheca. Both are typically subcircular structures lying close to each other between T8 (when present) and S8. The spermatheca is typically a lightly pigmented bowl shaped structure, as in Fig. 4, while the furca is hoop shaped and paler (S9 in Fig. 3). However in many species one or other or both these structures may be very pale and it may require critical adjustment of the microscope's lighting in order to discern them both. In observing a female mounted on a slide with its dorsal side uppermost, as one focuses downwards the sequence of encounter is T8 -furca (S9) -spermatheca -S8. Where an egg is in place ready for laying, then it lies below T8 and the furca but above the spermatheca and S8. Indeed the furca is often displayed to view most clearly against the background of such an egg. When no egg is in this position the furca may be tilted sideways on (as viewed from above or below). Etymology: the name refers to the relatively short hairs on the epandrium.

Male
A generally brown but not dark species. Head as Fig. 34. Postpedicel about as long as its greatest breadth. Palps as Fig. 34. The hairs of the abdominal tergites are fine and, apart from on T1, are not largely restricted to the hind margins. They are longest on T6. Venter hairs also fine or more so. Hypopygium as Figs 35 and 36. Legs brown but, apart from femora, only pale brown and tarsi even paler. Fronttarsus with posterodorsal hair palisade on segments 1 to 4 and segment 5 longer than 4. Hind femur as Fig Etymology: the name refers to the opposed tips of the costa and vein 3. Chonocephalus dahli Schmitz, 1928 [19]: 91.

Chonocephalus dahli Schmitz
The type material is mounted on 4 slides without any locality data or collection dates. Five localities and dates were listed by Schmitz. I have designated one of the cotypes (see below) as the lectotype.
A female caught at carrion at the same place and time as the specimen referred to below is assigned to C. secundus below.  This is the type species of the genus. It was described from females only. The type material was apparently destroyed by Wandolleck during the course of the dissections undertaken in order to make his detailed anatomical and morphological studies. A female from Fiji has been designated as the neotype (Disney [10]).
One of the many males from Fiji has three equally strong strong spines on the right gonopod where there is normally only one (Fig. 48). Etymology: the name refers to the elaborate hypopygium.
Two females on separate slides (in the MKB) were both labelled 'Holotype'! One of these has since been labelled as a paratype (Disney [10]).

Material
Holotype female, paratype female, New Guinea, Tinschhafen, under bark near termite nest, 16 May 1944, F. S. Ross Etymology: the name refers to the type locality.     This tramp species has been carried around the world by man. It has accordingly been repeatedly misidentified. It has been recorded from every Biogeographical Region (except the Antarctic), but is seemingly most abundant in Africa south of the Sahara (Disney [11]). Through the agency of man it is now reported throughout the warmer parts of the world and in glasshouses in temperate regions (Disney [4], [10]).

Natural history
The larvae and puparium were described by Borgmeier ([2]) (Figs 94-98). A female caught on the edible paddy straw mushroom Volvariella (Plutaceae) was probably ovipositing on an over ripe sporophore, as was the case with the females recorded on rotting Termitomyces (Amanitaceae) on a termite mound. It has also been reared from bread fruit (Artocarpus altilis (Parkinson) Fosberg, Moraceae) (Disney [7]). The series collected at turmeric (Curcuma longa L., Zingiberaceae) infested with larval Dichocrocis punctiferalis (Guenée) (Lepidoptera, Pyralidae) were possibly attracted to diseased or moribund caterpillars. Likewise a series reared from acocoon mass of Apanteles flavipes (Cameron) (Braconidae) were  Etymology: the name refers to the type locality.

Male
A generally light brown species with pale sides to the thorax and a very pale abdominal venter. However, the male from Henderson Island has a darker thoracic dorsum and abdominal tergites. Postpedicels as Fig. 149. Palp as Fig. 148. The hairs of the abdominal tergites 2-6 are fine and are largely restricted to the hind margins. They are only slightly longer at the rear of T6. Venter hairs smaller, very fine and few in number. Hypopygium as Figs 150-154. Legs dusky yellow (but the outer half of the hind femur is light brown in the specimen from Henderson Island). Front leg as Fig. 155. Hind femur, tibia and basitarsus as Fig. 156. Wing (Fig. 157), 0.8-0.9 mm long. Costal index 0.54. Haltere light brown (but darker in the specimen from Henderson Island).

Male
A generally pale brown species, with pale sides to the thorax and a pale abdominal venter. Postpedicel as Fig. 159. Palps as Fig. 158. The hairs of the abdominal tergites on segments 2 to 6 are fine and are largely restricted to the hind margins except 120 Review of Australasian Chonocephalus Wandolleck (Diptera: Phoridae) on T6, where they are longest at its hind margin. Venter hairs extremely small and fine and few in number. Hypopygium as Figs 160-162. Legs with mid and hind femora and hind tibia brown, and with a darker patch in the third quarter of the mid femur. The rest of the legs only lightly tinged, especially the mid tibia and all the tarsi. Front tarsus as Fig. 163, with posterodorsal hair palisades on segments 1 to 4. Hind femur as Fig. 164. Wing (Fig. 165)  Etymology: the name refers to the type locality. Chonocephalus major Schmitz, 1928 [19]: 92.

Chonocephalus major Schmitz
The hypopygium of the type is damaged and mounted so that the left face is tilted at an angle away from the viewer.

Chonocephalus mergi sp. nov.
Etymology: the name refers to the collector of the holotype. Chonocephalus palposus Schmitz, 1928 [19]: 101. The female has yet to be recognised, but C. primus (see below), which is only known in the female sex, has been caught at the same times and in the same localities both in the Bismarck Archipelago and in Fiji.

Material
Male

Male
A generally brown but not dark species with a pale abdominal venter. Postpedicel as Fig. 194. Palp as Fig. 193. The hairs at the sides of abdominal tergites are more numerous and longer than usual, those on T4 to T6 being more than 0.15 mm long (Fig. 195). Venter hairs fine and much smaller (Fig. 195). Hypopygium as Figs 196 & 197. Legs with coxae to femora brown along with the front and hind tibiae, the mid tibia white and the tarsi only lightly tinged. Front tarsus with a posterodorsal hair palisade on segments 1 to 4 and segment 5 longer than 4. Hind femur as Fig. 198  Etymology: the name refers to the type locality.

Key to the males of the Australasian Region
The males of C. elongatus, C. primus and C. secundus remain unknown or not yet associated with their males.
1 Surstylus (C) present and the most anterior bristle of the left side of the edpandrium differentiated (i.e. it is an S) so that is clearly more robust than the rest and may be spine like (e.g.  6 The posterolateral regions of the epandrium tapered and projecting rearwards (Figs 259 & 261). The vesicle at tip of wing vein 3 ill defined (Fig. 260). A fringe of fine, pale, minute hairs below basal third of hind femur (Fig.  264) Mid femur narrowed in its basal half (Fig. 128). Hypopygium as Tip of mid tibia and basitarsus as Figs 111 and 112. Hind femur with an irregular row of long fine hairs (longer than the more robust hairs on the anterior face) below the second and third fifths (Fig. 113). C absent