Revision of the wolf spider genus Diahogna Roewer, 1960 (Araneae, Lycosidae)

The Australian/Pacific wolf spider genus Diahogna Roewer, 1960 is revised with D. martensii (Karsch, 1878) as type species. In addition to D. martensii, of which the male is illustrated for the first time, the genus includes a further three species, D. exculta (L. Koch 1876), n. comb., D. hildegardae n. sp., and D. pisauroides n. sp. The presence of a basoembolic apophysis on the male pedipalp places Diahogna in an unnamed Australasian/Pacific subfamily of wolf spiders that also includes Anoteropsis L. Koch, 1878, Artoria Thorell, 1877, Notocosa Vink, 2003, and Tetralycosa Roewer, 1960. Diahogna differs from these mainly in the presence of a distinct apical extension of the tegulum on the male pedipalp. Somatic characters of Diahogna that are peculiar within the Lycosidae include eye arrangement, carapace shape, and body coloration which superficially resemble that of fishing spiders (Pisauridae). Lycosa neptunus (Rainbow, 1896) and Lycosa spinipes (Rainbow, 1896), both only known from the holotypes collected near Sydney, Australia, have been previously associated with D. martensii and D. exculta. As these types are immature specimens in faded condition, accurate species identification is impossible and both species are considered nomina dubia. All species of Diahogna are known from wet habitats, such as the margins of rivers, creeks, dams, marshes and swamps.


Introduction
The knowledge of morphological characters of the genitalia, in particular the structure of the male pedipalp, is crucial for an interpretation of phylogenetic relationships in wolf spiders at all taxonomic levels (e.g. Zyuzin 1985Zyuzin , 1993Dondale 1986). Early wolf spider taxonomists ignored the importance of differences in male genitalia resulting in a large number of paraphyletic and polyphyletic taxa (e.g. Roewer 1959Roewer , 1960Guy 1966;McKay 1979). Recent studies focusing on genital morphology in combination with somatic characters have resulted in a re-evaluation of a large number of Australasian wolf spider genera in a variety of subfamilies, for example Anoteropsis L. Koch, 1878 and Notocosa Vink, housed at the Museum national d'Histoire naturelle, Paris). The comparison of these specimens with the type material of L. exculta confirmed E. Simon's identification and the presence of Diahogna in New Caledonia.
All descriptions are based on specimens preserved in 70% ethanol. Female epigynes were prepared for examination by submersion in lactic acid for 2 h. For clarity, the illustrations of male pedipalps and female epigynes omit the setae. Photographs were taken with a digital camera (Canon G6) that was connected to the ocular tube of a stereo microscope (Leica MZ6) with an adapter set (Scopetronix MaxView Plus). Photographs were taken in different focal planes and combined with the software package Helicon Focus 3.10.3 (Khmelik et al. 2005).
The morphological nomenclature follows Framenau (2002Framenau ( , 2005, however, the term ''tegular apophysis'' is given preference over ''median apophysis'' for a structure of the male pedipalp as it more accurately describes its topology (see also Lehtinen 2005). The curvature of the anterior row of eyes was determined by the shape of an imaginary line through the centre of the eyes in frontal view. The anterior row of eyes is ''procurved'' if the ends of this line point downwards and ''recurved'' if they point upwards (see Roewer 1959 for a detailed discussion on lycosid eye patterns). Some confusion may arise in regard to naming the marginal bands on the carapace. In many lycosids, a light band of varying width is present along the carapace margin. This light band is referred to as a ''marginal band'' (e.g. Figure 1A). It becomes a ''submarginal'' band if there is a distinct dark band (usually of the same colour as the carapace) present between the light band and the carapace margin ( Figure 1D). All measurements are given in millimetres.

Diagnosis
Diahogna differs from all other wolf spider genera by the following combination of somatic and genitalic characters. The dorsal carapace profile is straight in lateral view ( Figure 2B),  the carapace itself is uniformly brown with a lighter area medially, sometimes in the form of a Y-shaped median band ( Figure 1A-D). The row of the AE is straight or slightly procurved and wider than the row of the PME ( Figure 2C). The row of the PLE is much wider than that of the PME giving the spider a pisaurid appearance ( Figures 1A-D, 2A). The abdomen is uniformly brown to olive-grey, a lanceolate heart mark can be present. Unique within the Australasian Lycosidae, in particular in contrast to the affiliated Artoria, Tetralycosa, Anoteropsis, and Notocosa, the tegulum of the male pedipalp is drawn out apically, i.e. it has a distinct apical tip ( Figures 2E, 5A, 7A, 9A). The tegular apophysis points apically or retrolaterally and has a truncated tip. The epigyne forms a heavily sclerotised plate without a clearly distinguishable median septum.

Description
Medium-sized wolf spiders (TL ca 6.0-14.0 mm). Males smaller than females. Carapace longer than wide, dorsal profile straight in lateral view ( Figure 2B). Head flanks in frontal view a gentle slope ( Figure 2C). Carapace brown, medially lighter (sometimes in the form of a Y-shaped median band) and with marginal or submarginal light bands enhanced by white setae. Anterior median eyes generally larger than anterior lateral eyes (of equal size in male D. pisauroides), row of anterior eyes wider than row of posterior median eyes; row of anterior eyes straight or slightly procurved. Chelicerae with three promarginal and three (rarely two or four) retromarginal teeth. Labium generally longer than wide (except female D. exculta and male D. pisauroides). Abdomen olive-grey with light lanceolate heart mark formed by white setae. Leg formula VI.I.II>III (VI.III.I.II in male D. exculta). Spination of legs: femur: two or three dorsal, one apicoprolateral, zero or two retrolateral; patella: zero or one prolateral; tibia one to three ventral pairs (basal pairs sometimes reduced to one or no spine), zero or one prolateral; metatarsus: three ventral pairs, one apicoventral. Tegulum longitudinally divided, retrolateral part narrow in ventral view. Tegular apophysis located retrolaterally at apical tip of tegulum, without basal lobe. Embolus originating prolaterally on palea and curving ventrally around it, long and slender. Basoembolic apophysis forms a white or transparent, membranous lobe. Terminal apophysis with bulging base. Epigyne with a heavily sclerotised plate, with two small (D. exculta, D. hildegardae) or a single, wide opening (D. martensii). Spermathecae round or ovoid, copulatory ducts distinctly narrower than spermathecae.

Remarks
A recent molecular phylogeny inferred from 12S rRNA and NADH1 including 70 worldwide lycosid species with the majority from the Australasian region, included D. pisauroides (as ''New Genus 2 sp.'') as representative of Diahogna (Murphy et al. 2006). Independent of the phylogenetic analysis used (parsimony, Bayesian), D. pisauroides represented the sister taxon of Tetralycosa oraria (L. Koch, 1876) within a distinct Australasian/Pacific clade at the subfamily level. Morphologically, this clade is characterised by the presence of a unique basoembolic apophysis on the male pedipalp and had previously been argued to represent a new lycosid subfamily (Framenau 2002;Vink 2002;Framenau et al. forthcoming). A formal description of this subfamily is forthcoming as part of my revision of the Australian Lycosidae.

Diagnosis
Males of D. martensii differ from D. exculta and D. hildegardae in a variety of structures in the male pedipalp, in particular the shape of the tegular apophysis, which is much smaller. The sperm duct, which is visible through the tegulum, has an S-shaped curve but it is straight in D. hildegardae. They can be easily distinguished from D. pisauroides by the carapace coloration as the latter is the only species with submarginal instead of marginal light bands ( Figure 1A, D). The female epigyne of D. martensii with its single posterior opening is unique within the genus.
Carapace: brown; indistinct dark radial pattern; light brown median band narrowing from behind PLE to just behind fovea; darker coloration centrally in median band results in a Y-shaped pattern of the median band; distinct light marginal bands through dense cover of white setae; otherwise brown setae; dark brown macrosetae in cephalic area and medially between PLE and fovea.
Eyes (Figure 2A, C): row of AE slightly procurved and wider than row of PME. Sternum: orange-brown; brown setae which are denser and longer towards margins. Labium: light brown, basally darker; front end truncated and white. Chelicerae: dark orange-brown; covered with light grey setae and brown macrosetae; three promarginal teeth, the median largest; three retromarginal teeth of similar size.
Abdomen: dark olive-grey; dense white setae form a lanceolate heart mark in anterior half; lateral light stripes reach along the whole abdomen; four pairs of small, widely separated light spots in posterior half; otherwise brown setae and dark brown macrosetae. Venter orange-brown; covered with light brown setae. Spinnerets light brown.
Carapace, eye, and labium: as male. Sternum: orange-brown. Setae as male. Chelicerae: dark reddish brown; setae and dentition as male. Abdomen: as male, but lanceolate heart mark very indistinct and no lateral stripes ( Figure 1A). Venter brown, setae as male. Spinnerets: light brown.
Epigyne, ventral view ( Figure 3A): simple sclerotised plate with a posterior opening that is much wider than long.

Distribution
South-eastern Australia, including New South Wales, South Australia, Tasmania, and Victoria ( Figure 4).

Life history and habitat preferences
Diahogna martensii is the most commonly encountered of the four species within the genus. Mature males and females have been found nearly all year round, with females peaking in October and November. The species appears to prefer moist conditions, such as swamps and marshes, and can also be found in the vicinity of rivers, lakes, and dams. References such as ''in water'' or ''apparently under water'' suggest that this species heavily utilises water sources, for example to hide from predators (such as collecting arachnologists).

Remarks
Although the holotype female of D. martensii is an immature specimen, somatic characters, in particular the distinct Y-shaped pattern on the carapace, allow an accurate identification of this species (see also McKay 1979).
The original specific epithet of this species was martensii (Karsch 1978). Bonnet (1957) amended this name to martensi (ending with only one -i ), and as such this species is currently listed (Platnick 2006;personal communication). However, the International Code of Zoological Nomenclature undoubtedly clarifies the case of alternative genitive endings of species-group names and ruled to follow the original spelling of the specific epithet (International Commission on Zoological Nomenclature 1999, Article 33.4).

Diagnosis
The distinctly two-lobed tegular apophysis that points apically in the male pedipalp of D. exculta is unique within the genus. Females of this species can easily be distinguished from D. martensii and D. hildegardae by the shape of their epigyne that has distinct sclerotised edges medially from the copulatory openings.

Description
Male. Based on MHNP 3877. Carapace: brown, indistinct light Y-shaped pattern medially; indistinct dark radial pattern; distinct light marginal bands; brown setae, white setae in marginal bands; dark brown macrosetae around eyes.
Eyes: row of AE slightly procurved and wider than row of PME. Sternum: orange-brown; brown setae which are longer and denser towards margins. Labium: brown, basally darker.
Female. Based on AM KS85056.
Carapace ( Figure 1B), sternum, labium and chelicerae: as male. Eyes: row of AE straight and wider than row of PME. Abdomen: uniformly olive-brown without a distinct pattern ( Figure 1B); covered with brown setae. Venter orange-brown with brown setae. Spinnerets light brown.

Distribution
Diahogna exculta has so far only been recorded reliably from the vicinity of Sydney, New South Wales (Australia) and Noumea (New Caledonia) (Figure 4). The record of the penultimate male paralectotype from Gayndah (Queensland) (Koch 1876;Rack 1961) must be treated cautiously since an accurate species identification of juveniles is not possible. Therefore, I omitted the record from Gayndah from the distribution map ( Figure 4).

Life history and habitat preferences
Collection dates (March and July) are only available for two females from Sydney, suggesting that this species may be autumn and/or winter active.
The collector of the type material, Mr Daemel, called this species ''water spider'' as he only found it in the proximity of water and apparently able to walk on the water surface (Koch 1876).

Remarks
Ludwig Koch (1876) described D. exculta from females from Sydney (New South Wales) and a juvenile male from Gayndah (Queensland). The female lectotype in the BMNH is labelled ''Sydney'', but the female and penultimate male specimens in the ZMH have no locality data. Taking L. Koch's (1876) original information into consideration, the specimens in the ZMH must be assumed from Sydney (female) and Gayndah (penultimate male).
Both male and female of D. exculta match closely the new generic diagnosis of Diahogna in somatic and genitalic characters. Consequently, this species is here transferred from the genus Trochosa.
Due to the fragile and bleached condition of the type material, the female of D. exculta is redescribed from a more recently collected specimen.

Etymology
The specific epithet is a matronym in honour of my mother, the late Hildegard Framenau. She never knew that I became a scientist.

Diagnosis
Males of D. hildegardae are easily distinguished from D. martensii and D. pisauroides by much larger tegular apophysis of the male pedipalp. In contrast to that of D. martensii and D. exculta the female epigyne of D. hildegardae does not have distinct sclerotised edges near the lateral copulatory openings.
Male. Based on holotype (AM KS75568). Carapace: brown, indistinctly lighter medially around and anterior of fovea; indistinct dark radial pattern; indistinct light marginal bands; brown setae, mainly white setae in submarginal bands; dark brown macrosetae around eyes; six long bristles below AE; one long black bristle between AME. Eyes: row of AE straight and wider than row of PME. Sternum: light brown, medially somewhat lighter; brown setae which are longer and denser towards margins.
Abdomen: uniformly dark olive-grey; light brown lanceolate heart mark in anterior half, brown setae. Venter light brown with light brown setae. Spinnerets light brown.
Legs: leg formula VI.I.II.III; brown, distal segments darker; two light annulations per segment caused by a ring of white setae. Spination of leg I: femur: three dorsal, one apicoprolateral; tibia: two ventral pairs, one basoventral, one prolateral; metatarsus: three ventral pairs, one apicoventral.
Carapace ( Figure 1C): brown, lighter medially between eyes and fovea; indistinct dark brown radial pattern; indistinct lighter marginal bands; brown setae, few white setae towards carapace margins; brown macrosetae around eyes in cephalic region; six macrosetae below AE; one long bristle between AME.
Eyes: row of AE straight and wider than row of PME. Sternum: yellow-brown; brown setae and macrosetae which are denser and longer towards carapace margins.
Labium: as male. Chelicerae: dark orange-brown; few white and grey setae mainly anteromedially. Abdomen ( Figure 1C): uniformly olive-grey with a very indistinct lighter heart mark in anterior half; covered with brown setae and fewer macrosetae. Venter light olive-grey with a few dark spots in posterior half; covered with light brown setae and dark macrosetae. Spinnerets light brown.

Etymology
The specific epithet is an adjective in apposition and refers to the pisaurid-like eye pattern and carapace coloration of this species.

Diagnosis
Diahogna pisauroides is easily distinguished from other species in the genus Diahogna by the carapace coloration, in particular the distinct submarginal light bands that are accompanied by dark marginal bands. All other Diahogna have light marginal bands.
Carapace ( Figure 1D): brown, distinct light median band filled anteriorly with brown centre resulting in a Y-shaped pattern, the base of which reaches to posterior carapace margin; indistinct dark brown radial pattern; distinct light brown submarginal bands and dark marginal bands; dark brown setae, mainly white setae in submarginal bands; dark brown macrosetae around eyes of which those below and between the AE are longest.
Eyes: row of AE straight and wider than row of PME. Sternum: brown; brown setae and dark brown macrosetae that are longer and denser towards margins.
Labium: dark brown, front end truncated and white. Chelicerae: brown, silver-grey setae and dark brown macrosetae; three promarginal teeth, the median largest; three (right chelicera: four) retromarginal teeth of similar size.