ON THE ANT GENERA ROMBLONELLA AND WILLOWSIELLA , WITH COMMENTS ON THEIR AFFINITIES , AND THE FIRST DESCRIPTIONS OF AUSTRALIAN SPECIES ( HYMENOPTERA : FORMICIDAE : MYRMICINAE ) BY

The originally monotypic genus Romblonella and its type-species R. grandinodis were described by Wheeler (1935) from the small central Philippines Island of Romblon (12 33’N; 122 17’E). Two species congeneric with grandinodis had in fact been described previously in the genus Tetramorium Mayr, namely R. scrobiferum (Emery, 1897) (Berlinhafen (= Aitape) (03 10’S; 142 17’E), Papua, New Guinea), and R. elysii (Mann, 1919) (Malaupina (= Malapina) I. (0951’N; 16050’E), Three Sisters Is, Solomon Islands) (Smith, 1956). Four additional species were later described by Marion R. Smith, as follows: R. townesi (1953A; Mt. Lasso, Tinian I. (1458’N; 14538’E), Northern Mariana Is); R. vitiensis (1953A: Wakaya I. (1739’S; 17901’E), Lomaiviti Group, Fiji Is); R. yapensis (1953A; Yap I. (0930’N; 13809’E), Caroline Is); and R. palauensis (1953B; Ulebsechel (-Auluptagel,-Aurapushekaru) I., Belau (-Palau) Group (07 03’N; 134 30’E), Caroline Is).


INTRODUCTION
The new species Romblonella heatwolei (Wyer Island, Torres Strait, Queensland) and Willowsiella anderseni (King Edward River, Kimberley District, Western Australia) are described below, and their affinities discussed. The genera, which are both new to the Australian fauna, are recognized as probable sister taxa in the tribe Leptothoracini, close to Leptothorax Mayr and Cardiocondyla Emery.
Four additional species were later described by Marion R. Smith, as follows: R. townesi  Manuscript received by the editor November 12, 1990. Psyche [Vol. 97 I have studied type material of all these taxa except R. scrobiferum, and consider all to be congeneric, representing valid species. All are worker-based, and the male has been described for R. palauensis. The workers of R. elysii, R. grandinodis and R. scrobiferum were originally illustrated, and Wheeler's figures of grandinodis were reproduced by Smith (1953A). Details of type deposition etc. are given in Smith (1956).
R. palauensis alone has been reported from sites beyond its type locality--from the Belau group islands Ngeruktabel (--Urukthapal) and Babeldaob (= Babelthaup) (Smith, 1953B Genus Willowsiella Wheeler, 1934 Willowsiella and its sole previously reported species W. dispar were described from a unique worker taken in 1933 on remote Bellona Island (1120'S; 15947'E), south of Guadalcanal, Solomon Islands (Wheeler, 1934). There have been no other records of genus or species until the recent unexpected collection of a congeneric worker in the Kimberley district of northern Western Australia. It is described here as Willowsiella anderseni n.sp. The characteristics and possible relationships of Willowsiella are discussed below.
Willowsiella dispar Wheeler, 1934 (Figs 4,5) W. dispar is adequately characterized by Wheeler's description and figures. It is compared below to the new species W. anderseni.
The holotype (California Academy of Sciences, San Francisco) is mounted on 2 points, one with the head, mesosoma and petiole, the other with the postpetiole and gaster. It carries a small red tag with the words "HOLOTYPE" (printed) and "W. dispar"(hand-written); a large label reading "'Willowsiella dispar Wheeler (Type)" in Wheeler's handwriting; and four small printed white data labels, reading respectively: "Solomon Islands"; "NW end of Bellona Isd, VI 23-33"; "M. Willows Jr. Collector"; and "Templeton Crocker The specimen has the following dimensions (mm; see above under  (1962) and Taylor (1976). The majority are either tramp species or widespread Indo-Australian elements. It is unlikely that any, including W. dispar, are truly endemic to Bellona.
Material examined: H olotype worker (1 June, 1988, A. N. Andersen). Deposited in ANIC (type number 7867). The holotype has been gold-palladium coated for scanning electron microscopy. It was unfortunately damaged in a laboratory accident, but its major parts are complete.
Head expanded posterolaterally; anterior part of frons somewhat inflated; clypeus inflated anteromedially, median anterior border transverse, shallowly concave, abruptly reflexed ventrally and projecting forwards to slightly overhang the closed mandibles. Mandibles 5-toothed, apical tooth the largest and most acute, the others subequal in size, diminishing slightly from apex. Antennal club indistinctly 3-jointed, the two apical segments enlarged.
Pronotal shoulders narrowly rounded in dorsal view, semiepaulate. Pronotum on each side with an obtuse ridge extending dorsally from its ventrolateral extremity to the shoulder, so that the anterolateral and lateral sections of the sclerite are more-or-less separated. Dorsum and sides of mesosoma lacking sutures, except for a short ventral section of the promesonotal suture on each side below the spiracle. Propodeal spines short but acute, posterodorsolaterally directed, slightly curved; each subtended by an anterodorsal carina, which defines the lateral margin of the propodeal Psyche [Vol. 97 dorsum; infradental lamellae small, rounded. Propodeal spiracle very small, situated near the middle of the relevant section of the lateral wall of the mesosoma.
Petiole and postpetiole as illustrated; the former much less bulky than in W. dispar, strongly transverse in dorsal view. Postpetiole similarly transverse, shorter at midline than petiole. Petiolar peduncle extremely short, slender; the spiracles minute, each surmounted by a strong angular process, which is clearly visible and approximately right-angular in dorsal view. Base of gaster quite deeply emarginate in dorsal view, closely reflecting posterior outline of postpetiole. Gaster somewhat broad and flattened, especially anteriorly; in side view more-or-less triangular, with apex anteriorly directed. Sting moderately strong, blade-like, without apical appendage.
Pilosity sparse; a few relatively long hairs on clypeus and mandibles, and on apex and underside of gaster; clypeus with a median and 2 lateral setae on anterior margin; shorter hairs sparse on underside of head. Fine pubescence everywhere moderately abundant. Sculpturing vaguely, densely foveolate on head, mesosoma and nodes; less distinct and more shining posteriad; overall somewhat reminiscent of some Crematogaster species. Gaster dorsally vaguely shagreened, dully shining. Colour bright yellow-brown; eyes black; mandibular teeth dark brown; gastral dorsum darkly infuscated, darkest medially.
Generic assignment: W. anderseni is confidently assigned to Willowsiella on the basis of the characters it shares with IV. dispar. They are reviewed below in discussion of the attributes of the genus, and in the list of features distinguishing IVillowsiella from Romblonella. These species seem more closely interrelated than either is to any known Romblonella species, so that Willowsiella and Romblonella are considered here to be valid, separately monophyletic, but related, possibly sister, taxa.
W. anderseni is readily distinguished from W. dispar by its much smaller size, very different petiolar and postpetiolar structure, and pale colour.

THE GENERA AND THEIR RELATIONSHIPS
Definition of the genera: The general features of the Romblonella worker caste were reviewed by Wheeler (1935) and Smith (1953A), and those of the male by Smith (1953B).
In addition, the worker has the palpal formula maxillary 5: labial 3 (scrobiferum and heatwolei dissected); and the sting is blade-like, narrower than deep, and lacks an apical appendage. Sides of propodeum eachwith a marked, very obtuse, broad diagonal ridge, the crest of which runs from the anteroventral sector of the sclerite, and passes just in front of the propodeal spiracle, to terminate near the bulla of the metapleural gland; the latter very small and posterolaterally directed; propodeal spiracle small, situated a little above and behind the mid-point of the lateral wall of the propodeum, directed posterolaterally. Petiole in dorsal view with a stout triangular projection on each side of the very short peduncle, above the spiracle. It appears that workers of all known Romblonella species are monomorphic.
Emendations and additions are required to Wheeler's 1934 diagnosis of Willowsiella, as follows" Antennal club distinctly 3-jointed in W. dispar, less clearly so in andersen# dorsum of clypeus and anterior part of frons clearly inflated in dispar, more so perhaps than implied by Wheeler's description, and even more so in ander-sen# configuration of sides of propodeum, propodeal spiracles and metapleural glands as in Romblonella; petiolar and postpetiolar structures varying considerably between the two species, as described, but with similarities, especially in the presence of spiracular projections on the petiole, and the structure of the postpetiole; gas-Psyche [Vol. 97 ter basally emarginate in dorsal view; sting as in Romblonella, blade-like, and lacking an apical appendage.
The unique holotypes of these rare species have not been dissected, but they appear on detailed inspection to have a 5:3 palpal formula, as in Romblonella.
Willowsiella and Romblonella share several features considered to indicate relationship between them. These include the general configuration of the mesosoma and nodes (despite the differences in the latter), and the fundamentally similar dental, fronto-clypeal, palpal and sting structures (the latter at least as visible without dissection). The two genera may be readily distinguished as follows (compare Figs 1-3 and 4-9 Postpetiole of more normal proportions, subspherical, more-or-less as long as wide in dorsal view, at most only slightly smaller than petiole; usually larger. Gaster not basally emarginate. Affinities and classification of the genera Despite differences of opinion concerning their higher classification, Romblonella and Willowsiella have been discussed consistently together by authors following Wheeler (1934Wheeler ( , 1935, implying their general acceptance as related taxa. There seems little doubt that they are, and that their separate status as probable sister genera is justified. The original assignments by Emery and Mann of Romblonella scrobiferum and R. elysii to Tetrarnorium are not tenable. The principal relevant characters distinguishing the two genera happen (per-Psyche [Vol. 97 haps for good phylogenetic reasons; see below) to be the same as those used by Bolton (1982: 321) to differentiate the major myrmicine genus Leptothorax Mayr from Tetramorium. They apply similarly to Willowsiella and preclude classification of Romblonella and Willowsiella in tribe Tetramoriini. Wheeler (1934Wheeler ( , 1935 assigned both genera to "Emery's tribe Meranoplini", which then comprised the taxa indicated in Wheeler's 1935 key to meranopline genera. Tribe Meranoplini has since been disbanded (Kugler, 1978), leaving Meranoplus of uncertain taxonomic position at tribal or genusgroup level, perhaps peripheral to the Pheidole genus-group (Kugler, 1978), but with some similarities to Willowsiella and Romblonella. The latter were indicated, but considered to be of doubtful taxonomic significance by Bolton (1981), and will not be further pursued here. The other meranopline genera, with some synonymy, were considered by Bolton (1981) to be relatives of Lordomyrma Emery, partly to constitute the Lordomyrma-group of genera. M. R. Smith at first (1953A) accepted Wheeler's placement of Romblonella in the Meranoplini, but later (1953B) rejected it on the basis of newly accessible male characters, and proposed allocation to "the tribe Myrmecinini, subtribe Podomyrmina (sic!) of Emery, 1922". This taxon included the Australasian genus Podomyrma and its apparent satellites, the sub-Saharan African Atopomyrmex Andr6 and Terataner Emery, and the Papuasian Dilobocondyla Santschi (along with Atopula Emery, now a junior synonym of Tetramorium (Bolton,!976), and Lordomyrma) (Emery, 1922). Podomyrma (with Australian junior synonyms Dacryon Forel and Pseudopodomyrma Crawley (Brown, 1973;Taylor and Brown, 1985)), Atopomyrmex, Diloboeondyla and Terataner remain associated at genus-group level, along with the aberrant eastern Australian Peronomyrmex Viehmeyer (Taylor, 1970;Bolton, 1981), and possibly also the Oriental Paratopula Wheeler and Madagascan Ireneopone Donisthorpe (Bolton, 1988).
I have suggested elsewhere (Taylor, 1990) that Podomyrma could be close to, or even congeneric with, Leptothorax. This prospect remains under consideration in my current studies on the species and species-group-level taxonomy and affinities of Podomyrma. Relationship between the two genera appears to be strongly supported, implying that Podomyrrna and its satellites properly belong in tribe Leptothoracini. If this is the case, Smith's placement of Romblonella and Willowsiella with Podomyrma and its relatives in effect implied relationship to Leptothorax. Bolton (1981, p. 45) also inferred relationship between Leptothorax and Romblonella/Willowsiella, when he noted that the latter genera "both show a triangular prominence on each side of the petiole near the base of the node, such as is commonly seen in leptothoracines" and continued "whether there is any sort of relationship remains to be seen, although there are similarities between Romblonella and some tropical species of Leptothorax". The character discussed is present, incidentally, in many species of Podomyrma.
The hypotheses that Willowsiella and Rornblonella are related to Leptothorax, and mght therefore reasonably be classified in the tribe Leptothoracini, are implicit in the above suggestions, and will now be addressed.
Leptothorax has been characterized, with a review of its genericlevel synonymy, by Bolton (1982:321). Examination of the relevant 6. head,frontal;7. petiole and postpetiole,dorsal;8. whole animal,dorsal;9. whole animal, lateral; see text for dimensions. diagnosis, and consideration of the details provided here regarding Willowsiella and Romblonella, indicates that the formal prescription of Leptothorax could readily be extended to include Willowsiella and Romblonella. It would need only to cite (1) the presence of unreduced antennal scrobes to cover Romblonella, and (2) changes in the specifications for petiolar and postpetiolar characteristics to cover both genera.
The Neotropical Leptothorax species wilda M. R. Smith (a sometime member of the genus-group taxon Nesomyrmex, which was synonymised under Leptothorax by Bolton, 1982), has purportedly "vestigial" antennal scrobes (Kempf, 1959:422). Kempf's use of the word "vestigial" implies derivation from an ancestor possessing non-vestigial scrobes, and that scrobes must therefore, in his view, have been present in the ancestry of modern Leptothorax species (assuming that Nesomyrmex and Leptothorax are genuinely related). The presence of antennal scrobes would not therefore necessarily preclude otherwise eligible taxa like Romblonella from classification in the Leptothoracini. I consider that the scrobes in wilda are genuinely vestigial, partly because of their barely reduced similarity to those of some Australian species of the Podomyrma novemdentata group, which share additional features of possible taxonomic significance with wilda and other Neotropical species of "'Nesomyrmex" and with some of the southern African Leptothorax species, notably L. humerosus Emery (see figs. 28 of Kempf, 1959;and 16 of Bolton, 1982). These same P. novemdentata-group species appear to be among the least derived in Podomyrma, most species of which lack antennal strobes. If these various taxa are truly related, the definition of tribe Leptothoracini must accommodate the presence of antennal strobes, as well as their alternative absence, and for that reason would not exclude Romblonella. Substantial diversity in petiolar and postpetiolar attributes (which does not quite extend to include the conditions in Romblonella and Willowsiella) is already accepted in Bolton's prescription for Leptothorax. I do not suggest that Leptothorax, Romblonella and Willowsiella should be considered congeneric, but that, in terms of their formal Psyche [Vol. 97 definition and fundamental similarities, the three genera may reasonably be considered relatives.
The aberrant mesosomal configuration represented in both Romblonella and Willowsiella might seem to preclude relationship with Leptothorax, which is generally more conservative in this regard. This is clearly not a particular problem, considering the broadly similar (presumably homoplasic) attributes of the Neotropical L. anduzei Weber (Kempf, 1959, fig. 12).
Apart from Leptothorax (which, despite some hesitation by Bolton (1982:322), I take to include the Neotropical Macromischa Roger as a junior synonym, following Baroni Urbani, 1978) and several parasitic northern hemisphere genera, the Leptothoracini currently includes only the widespread paleotropical genus Cardiocondyla Mayr, which was reasonably assigned to the tribe by Bolton (1982:311) (with the dissolution of tribe Cardiocondylini). Francoeur and Loiselle (1988), incidentally, on the basis of male genitalic attributes, have suggested that Cardiocondyla is more closely related to "'Nesomyrmex" (which they did not consider to be a junior synonym of Leptothorax) than the latter is to their Leptothorax s. str.
There are marked similarities between Willowsiella and Cardiocondyla in the structure of the clypeo-frontal area (which for Cardiocondyla is "hinted at in some species of Leptothorax'" (Bolton, 1982:311)), the transversity of the postpetiole, the reduced pilosity, sculpturation etc. These features might not be homologous, but they certainly reinforce the argument that the definition and possible phylogenetic integrity of the Leptothoracini would not be challenged by inclusion of Willowsiella in the tribe.
On these grounds I propose that Romblonella and Willowsiella should now be assigned to tribe Leptothoracini, along with Leptothorax, Cardiocondyla, and the various parasitic genera discussed by Bolton (1982). A further review in this context of Podomyrma and its satellites is in preparation, with discussion supporting an hypothesis of early Gondwanic diversification of the Leptothoracini, relative to which the northern hemisphere Leptothorax species are derivative and peripheral.