Stanwellia, RAINBOW & PULLEINE, 1918

GENUS STANWELLIA RAINBOW & PULLEINE, 1918 View in CoL

FIG. 18 View Figure 18

Stanwellia Rainbow & Pulleine, 1918: 164 View in CoL . Type species: Stanwellia decora Rainbow & Pulleine, 1918 View in CoL (junior synonym of Chenistonia hoggi Rainbow, 1914 ), by monotypy.

Aparua Todd, 1945: 390 . Type species: Aparua bipectinata Todd, 1945 , by original designation.

Diagnosis: Stanwellia differs from other species of Australasian Anamini by the lack of a posterior heel on the maxilla, the absence of cuspules on the posteromesal corner of the maxilla ( Fig. 18B View Figure 18 ), and the presence of flexuous tarsi.

D e s c r i p t i o n: S m a l l t o l a r g e n e m e s i i d s p i d e r s. Coloration: ranging from pale to dark brown.

Cephalothorax: Carapace ( Fig. 18A View Figure 18 ) strongly to sparsely hirsute, with eight eyes in two rows; PME slightly smaller than other eyes; fovea straight to procurved. Maxilla without strongly produced basal heel; with numerous cuspules confined to anterior ectal corner; maxillary serrula usually present. Labium ( Fig. 18E View Figure 18 ) wider than long, slightly indented anteriorly, sometimes with cuspules. Coxal cuspules absent ( Fig. 18B View Figure 18 ). Sternum ( Fig. 18B View Figure 18 ) with three pairs of sigilla; posterior pairs rounded, situated near lateral margin.

Chelicera: Rastellum usually present; cheliceral furrow with several prominent promarginal teeth and several small granules basomesally; intercheliceral tumescence absent.

Pedipalp ( Fig. 18C, D View Figure 18 ): Male tibia uniformly setose, without patch of spinules on retrolateral face, and without asetose ventral depression; tarsus (cymbium) short and terminally blunt, without medial constriction (in lateral view); with simple pyriform bulb and tapering embolus; embolus not reflexed.

Legs: Male tibia I ( Fig. 18F View Figure 18 ) without ventral spur; metatarsus I not incrassate; scopula usually present on all tarsi of males; tarsi flexuous and without spines; tarsus I not inflated; three claws, lateral claws each with two short rows of teeth; medial claw small and without ventral teeth.

Abdomen: Longer than wide. Two pairs of spinnerets; posterior median spinnerets unsegmented and separated by about diameter of spinneret; posterior lateral spinnerets three-segmented, apical segment elongate, digitiform.

Female genitalia ( Fig. 18G View Figure 18 ): One pair of spermathecae of lobate spermathecae.

Remarks: Although considered a member of the Anaminae based on morphological criteria ( Raven, 1985b), alternative phylogenetic positions for Stanwellia have since been proposed. In a cladistic treatment based on morphological characters, Goloboff (1995) found Stanwellia to group with Acanthogonatus , Pycnothele , Rachias and Stenoterommata from South America and Hermacha from South Africa. This alternative placement for Stanwellia with Acanthogonatus and Stenoterommata was also recovered by Bond et al. (2012) and Leavitt et al. (2015). Bond et al. (2012) found these three genera to be sister to Fufius , a result that was also recovered in our analysis, albeit with weak support ( Fig. 2 View Figure 2 ). Wheeler et al. (2017) recovered a Stanwellia + Acanthogonatus clade as sister to all other Nemesiidae , while Leavitt et al. (2015) found the Stanwellia , Acanthogonatus , Stenoterommata clade to be sister to Pionothele , with Fufius sister to Brachythele Ausserer, 1871 , from Europe. Our analyses consistently failed to recover Stanwellia as part of the Anamini ( Fig. 3 View Figure 3 ). In the three gene analysis ( Fig. 2 View Figure 2 ), it formed a group with Acanthogonatus and Stenoterommata , similar to the results of Bond et al. (2012) and Leavitt et al. (2015), and Raven (1985b) also inferred a sister-group relationship between Stanwellia and Acanthogonatus . If a close relationship between Stanwellia , Acanthogonatus , Stenoterommata and Pycnothele is maintained, as proposed by Goloboff (1995), the subfamily-group name Pycnothelinae Chamberlin, 1917 is available for this clade ( Chamberlin, 1917).

The New Zealand specimens of Stanwellia used in this study nested within the Australian clade ( Fig. 3 View Figure 3 ), rendering Stanwellia as the only nemesiid genus that occurs in both Australia and New Zealand. The New Zealand species were previously included in the endemic genus Aparua (e.g. Todd, 1945; Forster & Wilton, 1968) until Main (1983) treated the latter as a junior synonym of Stanwellia .

Included species: Australian species: Stanwellia annulipes (C.L. Koch, 1842) ; S. grisea (Hogg, 1901) (= Aname arborea Hogg, 1901 ; A. pellucida Hogg, 1901 ; I. gregori Hogg, 1901 ; Chenistonia major Hogg, 1901 ; A. butleri Rainbow & Pulleine, 1918 ); S. hoggi (Rainbow, 1914) (= S. decora Rainbow & Pulleine, 1918 ; Aname decora Rainbow & Pulleine, 1918 ); S. inornata Main, 1972 ; S. minor (Kulczynski, 1908) ; S. nebulosa ( Rainbow & Pulleine, 1918) (= Aname confusa Rainbow & Pulleine, 1918 ); S. occidentalis Main, 1972 ; S. pexa (Hickman, 1930) .

New Zealand species: S. bipectinata ( Todd, 1945) ; S. hapua ( Forster, 1968) ; S. hollowayi ( Forster, 1968) ; S. houhora ( Forster, 1968) ; S. kaituna ( Forster, 1968) ; S. media ( Forster, 1968) ; S. puna ( Forster, 1968) ; S. regia ( Forster, 1968) ; S. taranga ( Forster, 1968) ; S. tuna ( Forster, 1968) .

PROBLEMATIC ANAMINE TAXA AND AVENUES FOR FUTURE RESEARCH

While our taxon sampling of Australasian Anaminae (sensu Raven, 1985b) is relatively broad, at least at the generic level, there are some taxa that require further research to test their systematic placement and answer lingering questions regarding their relationships. For example, the monophyly of the genus Namea could not be confirmed with our dataset, and the morphological features of some species preclude a straightforward diagnosis ( Raven, 1984a). In particular, two species from south-eastern Queensland, N. callemonda and N. dahmsi , lack the laterally originating embolus that occurs in other species of the genus ( Raven, 1984a) and in all other taxa assigned by Main (1985a) to the Teylini . Raven (1984a) and Main (1985a) highlighted the anomalous morphology of both of these species and suggested that they might be better placed in a new genus. We recommend that sequence data be used to elucidate their relationships more effectively, and that a variety of Namea species will help to test the monophyly of this morphologically diverse assemblage of taxa. Similarly, females have not yet been attributed to any of the species of Hesperonatalius ( Castalanelli et al., 2017) , and males of Kwonkan turrigera are currently unknown, although our analysis hypothesizes that they will possess a field of spinules on the retrolateral face of the pedipalpal tibia, similar to other species of Kwonkan .

Finally, the phylogenetic placement of the genus Stanwellia can now only be more fully resolved using multi-gene molecular datasets from a broad range of nemesiid taxa. While the analyses undertaken thus far suggests a close relationship with the South American genera Acanthogonatus and Stenoterommata , and possibly also Fufius and Pionothele ( Bond et al., 2012; Leavitt et al., 2015), samples of many other taxa are required to adequately test these hypotheses. Such research will also help determine the monophyly and limits of the Nemesiidae , which may be at best paraphyletic, or at worst polyphyletic.