Poltys C.L. Koch

Smith, H. M., 2006, A Revision of the Genus Poltys in Australasia (Araneae: Araneidae), Records of the Australian Museum 58, pp. 43-96 : 46-52

Genus Poltys C.L. Koch

Poltys C.L. Koch, 1843: 97 . Type species Poltys illepidus C.L. Koch by monotypy. Simon, 1885: 448, 1895: 888; Keyserling, 1886: 123; Pocock, 1900: 235; Rainbow, 1909: 230; Roewer, 1942: 904; Bonnet, 1958: 3746; Barrion & Litsinger, 1995: 579; Platnick, 2005.

Pleuromma Doleschall, 1859:44 . Type species Pleuromma moluccum Doleschall. First synonymized by Thorell, 1878: 28.

Cyphagogus Günther, 1862: 2 . Type species Cyphagogus mouhoti Günther. (Preoccupied in Coleoptera ).

Cyphonethis Thorell, 1869: 37 . Replacement name for Cyphagogus . Not recognized by Simon, 1885: 449, who synonymized Cyphagogus with Poltys .

Mastigosoma Ausserer, 1871: 817 . Type species Mastigosoma idae Ausserer. First synonymized by Simon, 1885: 449.

Gerrosoma Bradley, 1876a: 223 . Type species Gerrosoma papense Bradley. First synonymized by Thorell, 1881: 59, but disputed by Simon, 1885: 449.

Rhyncharachne Bradley, 1876b: 240 . Type species Rhyncharachne dromedaria Bradley. First synonymized by Thorell, 1881: 59.

Remarks. The generic synonymies listed above have not been questioned in this work. Only two of the type specimens involved ( P. mouhoti and P. idae ) have been located (see Appendix 1). Although these females share many Poltys characters ( Fig. 244), these taxa cannot be fully evaluated until males are known. Of the others, the original descriptions and figures do not contradict identification with Poltys .

On Poltys illepidus : at least six Poltys species are now known to occur in the area around Bintang, the type locality of P. illepidus (see Appendix 1). Koch’s type specimen, from the collection of Herr Professor Reich of Berlin, has not been located, nor apparently has that of Atea incerta C.L. Koch , described from material in the same box, which is now listed as nomen dubium under Araneus Clerk ( Platnick, 2005) . Even if the Poltys type were found, it might not be possible to identify the species, as the “female” specimen was missing its abdomen.Despite this, the identity of the genus itself is not in doubt. The combination of carapace shape, size and eye arrangement is distinctive. It is hoped that future work on the Asian Poltys species (or rediscovery of the type) will resolve this issue. For the time being, the species referred to as P. illepidus is one of the most common and widespread, has definitely been recorded from the general area of the type locality, and is that which most people associate with the name P. illepidus (e.g., Chrysanthus, 1961; Davies, 1988 [female only]). Continuing this association would therefore seem prudent unless better evidence becomes available.

Diagnosis. Females. All Australian Poltys species are medium to large spiders (carapace length 2.69–8.75) with a distinct eye tubercle and a pear-shaped carapace in dorsal view ( Fig. 35). Viewed laterally, the carapace is doublydomed ( Fig. 33). The median eyes form an anterior quadrangle on the eye tubercle, ALE are a variable distance posterior to these towards the base. The PLE are well separated from the ALE on the outer radius of the anterior carapace ( Fig. 35). In Asia, some species of the P. mouhoti - group have a reduced eye tubercle (as Fig. 244 or shorter), but eye arrangement and carapace shape are still distinctive. Heurodes Keyserling (Australian) and Cyphalonotus Simon (non Australian) are most frequently confused with Poltys but can be separated by the eye positions and genitalia. In Heurodes , the lateral eyes are adjacent (the “normal” araneid arrangement). In Cyphalonotus , the eyes may be slightly separated and are sometimes on an eye tubercle, but both lateral eyes are on, or at the base of, the eye tubercle (rather than the PLE being far away on the carapace). In both genera the epigyne has a bulbous basal part with a thinner extended scape. Micropoltys Kulczyński (northeastern Australia and New Guinea) also have separated lateral eyes but the females are as small as males and have no distinct eye tubercle. Males. Small compared to females (carapace length 0.78– 1.41); the lateral eye separation is distinctive when combined with the absence of secondary sexual characters such as endite teeth and coxal hooks ( Figs 56, 59). The eye tubercle is not always clearly differentiated. Micropoltys is similar in size and appearance, but Micropoltys have a more complex palpal organ with a large TA, plus endite teeth and coxal hooks. Although sometimes misidentified as Poltys , Heurodes and Cyphalonotus males are large (almost the same size as females) and also have endite teeth and coxal hooks. Males and females of Cyphalonotus and Micropoltys are illustrated in Smith (2005); Heurodes is illustrated in Davies (1988).

Description (Australian species). Females. Prosoma. Carapace pear-shaped in dorsal view, usually convex at coxa

I ( Fig. 35) (except P. frenchi , Fig. 130), widest between coxae II and III, longer than wide with a distinct eye tubercle anteriorly. In profile, carapace usually highest immediately anterior to fovea, double-domed ( Fig. 69); fovea a deep pit; eye tubercle level to distinctly elevated (occasionally higher than thorax), sometimes with small protrusions above PME ( Fig. 174). Eye tubercle and parts of caput hirsute, posterior carapace more or less glabrous ( Fig. 69). Chilum two slender curved plates ( Fig. 129). Chelicerae robust with three ( P. laciniosus -group) or four (most other groups) promarginal teeth, few to several retromarginal teeth and a varying number of denticles in the cheliceral groove ( Fig. 77). Cheliceral fang well developed, quite long, usually with tips crossed in mouth recess between maxillae. Labium wider than long ( Figs 75, 129), strongly rebordered with white margin. Maxillae robust, with serrula, cupping deeply recessed mouth, medial borders white. Sternum cordate with anterior concavity for labium, tip pointed between coxae IV. Sternum carries sclerotized articulating extensions at bases of posterior legs (and sometimes also leg II, Fig. 129). Eyes. Median eyes in a roughly equilateral quadrangle at or near anterior of eye tubercle, widest at either AME or PME ( Figs 3, 162); AME often partially or wholly directed ventrally ( Fig. 75). ALE on lateral eye tubercle, often partially directed ventrally on small one-sided tubercle; PLE well separated from ALE on lateral anterior carapace, directed posterolaterally. Tapeta in all secondary eyes: PME reduced to a sliver in base of eye-cup, ALE tapetum c. 1 ⁄ 3 in anterodorsal position in cup, PLE c. ¼ in anterior cup. Legs. 1243. Front femora varying in shape from a normal, slightly broadened cylinder ( P. illepidus -group, Fig. 33) to distinctly expanded dorsoventrally, with greatest diameter ½ to 2 ⁄ 3 distance to apex (e.g., Fig. 73); femur III fairly robust but short, femur IV longer and slender; few macrosetae on dorsal and prolateral faces of femora. Apical and lateral patellar macrosetae sometimes modified by flattening ( Figs 37, 123). Anterior tibiae with characteristic shape: in lateral view sinuously curving towards apex ( Fig. 33), with a “D” shape in cross-section, in dorsal view also curving laterally ( Fig. 3); dorsal surface almost flat with regularly spaced short macrosetae, prolaterally with numerous short and long curved erectile macrosetae that continue to the distal metatarsus ( Fig. 73); tibia ventrally smooth and glabrous (this is usually held close against the femur and cephalothorax when in cryptic day-time resting position, Figs 3, 5, 6). Anterior metatarsi gently curved, macrosetal patterns continuing from tarsi but also with paired macrosetae on ventral surface. Tarsi without macrosetae but on legs I and II a prolateral row of slightly stronger setae bear one or more basally notched teeth. One or more nearby hair rows also toothed but these are less specialized. Tarsi III and IV bear similar setae ( Fig. 24, example of notched tooth arrowed). Tarsal claws. Three claws, main claws pectinate with 6–8 teeth. Toothed accessory hairs near claws ( Fig. 22); on retrolateral tarsus IV the accessory hairs are enlarged but untoothed (not examined on legs II and III) ( Fig. 23). Female pedipalps are variable in dimensions, and in development of macrosetae. Abdomen. Certain shapes are characteristic of a particular species group but generally variable within and between species. Often with humps and tubercles and smooth and roughly haired patches. Also often with well-developed small sclerotized plates (“microsigillae”) scattered over the abdomen surface, especially in noblei (7, photo: David Hain); 9, P. frenchi . Arrows point to the anteromedial tip of the abdomen.

P. illepidus -group and P. frenchi -group ( Fig. 38). The pedicel is situated in the posterior half of the abdomen, so the abdomen is held at a steep angle overhanging the cephalothorax ( Figs 53, 73). Book lung covers yellow with approximately nine main grooves. Spinnerets. Normal araneid conformation ( Coddington, 1989; Scharff & Coddington, 1997; Griswold et al., 1998). ALS: MAP and nubbin medial ( Figs 16, 19); piriform field widely distributed, but a large variation between checked species with approximately 225 spigots counted in the illustrated P. illepidus ( Fig. 17), 95 in P. laciniosus Keyserling ( Fig. 18), and 80 in P. milledgei n.sp. ( Fig. 19). PMS: all spigots on anterior two-thirds of area; mAP + nubbin posterior; aciniform brush relatively sparse, about 14 spigots, grouped in anteromedial corner ( Fig. 20). PLS with basally placed cylindrical spigots, closely grouped triad and approximately 30–40 aciniform spigots ( Fig. 21). Epigyne. Short and broad or a longer triangular or diamond-shaped plate ( Figs 26, 28, 30, 32). Anterior plate rebordered giving a deep rim around the distal margin and laterally to a varying extent ( Figs 46, 195). Most species with a distal bulge at the midline in lateral view ( Figs 54, 191), and/or a pair of secondary bulges ( Figs 47–48) that may appear as lobes ( Fig. 140– 141). Posteriorly with a median plate at least basally, reduced to a ridge of variable height away from the base in species with medium–long epigynes ( Figs 47, 196); broad and fused with, or closely adjacent to, the lateral plates for much of the length in P. columnaris -group ( Fig. 105). Foveal shape diagnostic for most species. Glandular spermathecae lie at the base of epigyne just within the abdomen. Copulatory ducts either lost or appearing as a posterior lobe of the spermathecae in the P. illepidus -group, with only pores leading away from the visible external parts of the epigyne ( Fig. 26). In other groups there are short to medium length copulatory ducts along the lines where posterior lateral plates fuse with the median plate ( Figs 28, 30, 32). Colour. Variable. The only fairly consistent areas of colouration are those that are not involved in cryptic camouflage: most species have at least some black colouration around the secondary eyes, especially on the slightly tubercular lateral eyes; dorsal eye tubercle and adjacent areas of caput usually orange to creamy-yellow, remaining carapace is usually dark in the P. illepidus -group and P. laciniosus , paler in others; caput hairs always pale, usually appear whitish at least in alcohol specimens; ventral femora of P. illepidus -group usually dark with a deep blue refractive shine. The femora of other species groups are pale or yellow–orange contrasting with one or more dark bands, where the blue shine may again be apparent. Green pigments occur in some specimens both on the abdomen and on the legs, most commonly in tropical species but also as paler bluey-green lichen-like patches in southern species. Green pigments quickly break down in alcohol.

Males. Many features are like juvenile females at a similar stage of development (2–4 moults). In somatic characters, early maturing males can be quite different from late maturing males of the same species (e.g., as shown Figs 203–206). Prosoma. Carapace. Mostly pear-shaped in dorsal view, widest between coxae II and III, longer than wide with a poorly to well-defined eye tubercle anteriorly ( Figs 58, 98), sometimes with small protrusions above PME ( Fig. 198). In profile ( Fig. 56) carapace more-or-less level or highest at eye tubercle. Chelicerae similarly proportioned to female. Cheliceral fangs short to medium. Labium and maxillae similar to female with white or pale edges, endite tooth absent ( Fig. 59). Sternum similar shape to that of female but reinforced by sclerotization that continues around between coxal bases to meet similar continuations from areas dorsal to the coxal bases. Eyes. As female but ocular area more compact and eyes relatively larger ( Fig. 59) and rather variable in relative sizes. Legs. 1243. No coxal hooks. Femora almost straight in most species, slightly broadened in P. columnaris -group ( Figs 95, 100); macrosetae as female. Patellar macrosetae as female. Anterior tibiae almost straight ( Fig. 56); dorsal macrosetae may be flattened as on patellae ( Fig. 99); prolaterally with a few macrosetae. Larger males, which have been through more moults, have a few more macrosetae ( Fig. 207), but juvenile females are developing mature female-like legs with more macrosetae by this stage. Metatarsi also with only a few macrosetae. Abdomen. Book lung covers smooth. Abdominal shape similar to females of similar size, i.e. some differentiation of shapes developing but still basically ovoid ( Figs 199, 202). Palpal organ. A more or less full complement of typical araneid sclerites is present in most species but some structures (especially TA where present) are rather simplified. Expanded views of the Australian species groups are shown in Figs 25, 27, 29, 31. Of the tegular sclerites, all species have a long slender MA with a broad base ( Figs 70, 208); a conductor is present that is reduced in the P. columnaris -group but is sturdy in others ( Figs 118, 218); and a third sclerite is labelled here as a paramedian apophysis (PM). This is closely associated with the base of the MA and is possibly a separated section of that sclerite. The PM is well developed in P. frenchi and P. laciniosus -groups ( Figs 125, 219), is smaller in the P. illepidus -group ( Fig. 70) and extremely small or absent in P. columnaris -group (a small sclerotized patch with label “PM?” on Fig. 27). This sclerite appears to be homologous between these Poltys species-groups, but is not necessarily homologous to the PM of other taxa (see Scharff & Coddington, 1997, for a discussion). In the embolic division all taxa have a radix; a stipes and distal haematodocha is definitely present in P. illepidus and P. frenchi , probably also in other species ( Figs 25, 29, 67); a long, narrow TA that widens to a lamina distally is present in P. illepidus - group and P. frenchi -group ( Figs 25, 29, 126), is shorter but broad in P. columnaris -group ( Figs 27, 118) but absent in P. laciniosus -group ( Figs 31, 218); the embolus varies between a short, stout rod in P. columnaris -group ( Fig. 118) to a long, wire-like, grooved structure in P. laciniosus -group ( Fig. 218). The paracymbium is a well-developed hook ( Fig. 25). Femoral tubercles are absent. Macrosetae are absent from the palpal patella. • Colour. Less variable than females. Most species have at least some black colouration around the secondary eyes. Prosoma and legs mostly pale olive/ brown, usually with black markings in centre of carapace and orange or yellow on the dorsal eye tubercle. Distal metatarsi and tarsi usually pale with dark rings. Larger males usually more strongly coloured than smaller specimens. Abdomens a pattern of brown/grey and black on white.

Biology. Most observations have been carried out on the P. laciniosus -group; a more detailed account will be provided separately (Smith, unpublished data). Except for adult males, all Australian species of Poltys make a web at night, which is usually ingested around dawn. The sticky spirals and radii are closely placed ( Figs 10, 12). Moths are a major prey item, but other insects are also taken. The spiders seem to prefer openings in the vegetation, which may form natural flight corridors for moths and other prey. Webs have been recorded at heights between 0.2 m to around 4 m from the ground. The daylight hours are spent resting in a cryptic position on a nearby twig, tree-trunk, in low herbage ( Figs 1–2, 3–9) or in a curled leaf ( Robinson et al., 1974). Dead twigs are preferred, especially by southern Australian species, but tropical species are more frequently associated with living vegetation. Egg sacs are laid on twigs or leaves ( Figs 10 (arrowed), 13–15).

Distribution. Poltys species are found from equatorial western and southern Africa through southern Asia and south to mainland Australia, north to Japan and on at least some southern Pacific islands. Within Australia half of the species are only present in the far north. No Poltys have been recorded from either Tasmania or New Zealand.

Relationships. Within the Araneidae , Poltys appears to be a rather uniquely derived taxon with no close sister groups yet identified. Data from a study using the araneid matrix developed by Scharff & Coddington (1997) suggest that Poltys is most likely placed in the basal araneines and may be related to some or all of the taxa from Scharff & Coddington’s “ Hypsosinga clade” ( Smith, 2005). As reported, however, by Scharff & Coddington and corroborated by another study based on this data set, some elements in the basal Araneidae are rather labile, especially when additional taxa are added ( Kuntner, 2002). In particular, there is some equivocal evidence with respect to the relationships between argiopines and the basal araneines. For instance, the apparently distinctive character seen on femur IV of Poltys elevatus Thorell ( Fig. 243) is also present in Caerostris Thorell ( Grasshoff, 1984) , which is an “argiopoid” genus; Scharff & Coddington commented that the “argiopine clade” genera frequently appeared in the basal “araneines” in their data set; Smith (2005) found that Arachnura Vinson and Witica O.P.-Cambridge frequently moved into this area. The placement of Poltys in the basal araneines should therefore be considered provisional.