Cheiracanthium insigne

Dankittipakul, Pakawin & Beccaloni, Janet, 2012, Validation and new synonymies proposed for Cheiracanthium species from South and Southeast Asia (Araneae, Clubionidae), Zootaxa 3510, pp. 77-86 : 78-81

Cheiracanthium insigne O. P.– Cambridge, 1874

Figs 1–9

Cheiracanthium insigne O. P.– Cambridge, 1874: 408, plate 52, fig. 32; description of male and female. Gravely, 1931: 266, figs 17L– M. Tikader & Biswas, 1981: 70, fig. 122. Chen & Zhang, 1991: 252, figs 264.1–4. Majumder & Tikader, 1991: 60, figs 113–116. Song, Zhu & Chen, 1999: 413, figs 243K–L.

Eutittha gracilipes Thorell, 1895: 47 ; description of male. New Synonymy

Type material. Syntype of C. insigne : 3, INDIA, Assam: no date, leg. E.W.P. Cambridge ( NHML, examined). Original label presumably lost, type accompanied by a label written by museum curator Reginald Innes Pocock: / 1898.3.20.30.; Cheiracanthium insigne ; Cambr.; Assam.; E.W.P.C./.

Holotype of E. gracilipes : 3, MYANMAR, Bago Division: Tharrawaddy, leg. E. Oates, no date ( NHML). Original label: / Eutittha ; gracilipes Thor. ; Tharrawaddy, Burma; Oates/.

New material. THAILAND, Pathum Thani Province: 1♂, Klong 9, mango orchard, 20 December 2005, leg. W. Vungsilabutr ( EZTH, ENT –117). Samut Songkhram Province: 3♂, Bangkontee District, mango orchard, 17 November 1999, leg. W. Vungsilabutr ( EZTH, ENT –118). Bangkok Province: 1♂, Bangkhen District, mango orchard, no date, leg. W. Vungsilabutr ( EZTH, ENT –119).

Remarks. Thorell (1895: 47) gave a formal description of a single male spider collected from Tharrawaddy followed by the description of a single female from Rangoon ( Thorell 1895: 48) as E. gracilipes in his Descriptive Catalogue of the Spiders of Burma. No significant differences were detected between the male types of C. insigne and that of E. gracilipes Thorell, 1895 . Therefore, we propose a formal synonymy, Eutittha gracilipes as a junior synonym of C. insigne O. P.– Cambridge, 1874. Our study of the types and additional material indicates that all males of this species ( Figs 1, 3–7 ) have narrow and very long tegular flanges that are semi-transparent, extending prolaterally and posteriorly; the ribbon-shaped embolus is elongated and runs along the margin of the tegular flange; the tegular apophysis is absent; the baso-retrolateral spur on the cymbium is short and triangular.

As for the female of E. gracilipes, Thorell provided the following remark ‘Si propriae speciei est haec femina, E. truncata appelletur’ (‘If this female is a species of its own, then it should be called E. truncata ’). Thus, Thorell was not convinced that both specimens belong together in the same species, but he had considered the possibility and therefore added this particular remark. Unlike the male of E. gracilipes , the female type does not resemble that of C. insigne . Consequently, it cannot be synonymized with latter species. It was considered a separated species from E. gracilipes and the name truncata is proposed (see below). According to the ICZN (2000) article 12.1 the name E. truncata is available as it satisfies the requirements: it has been accompanied by a description.

The identity of the C. insigne females is problematic. O. P.–Cambridge mentioned in the species description that ‘the genital aperture is small and of a narrow transverse kidney-shape’. He also provided an illustration of the epigynal area of the female syntype ( O. P.– Cambridge 1874; fig. 32b). This illustration together with an original description is the only reliable source of information on the female. Later, Gravely (1931; fig. 17M) provided an illustration of the epigyne of C. insigne , which is quite similar to that of E. truncata , but it bears little resemblance to that of C.insigne made by O. P.–Cambridge. Gravely (1931: 266) stated that ‘the only female [of Eutittha ] in the collection is the one lent by the British Museum from Rangoon’ so the female syntype of C. insigne was apparently not available at the time he received material from the NHML. It comes as no surprise when Gravely ‘find no satisfactory distinction between E. gracilipes from Burma and C. insigne from India [on the basis of the male palpal morphology. See also Gravely 1931: fig. 17L]’ and ‘all should be united into a single species’. The illustration of female C. insigne in Gravely’s work was undoubtedly based on the type of E. truncata from Rangoon on an assumption that E. truncata is a true conspecific female of C. insigne , being unaware of the significant differences between the female genitalia of these two species. The result of incorrect matching of the conspecific sexes is very obvious: although males of C. insigne were subsequently collected and illustrated several times, no record of a female was documented i.e., Tikader & Biswas (1981; male only), Chen & Zhang (1991; male only), Majumder & Tikader (1991; male only), Song, Zhu & Chen (1999; male only). O. P.–Cambridge clearly mentioned that the type series of C. insigne was made from the Bombay Collection presented to the museum by Major J. Hobson and from the Ceylon Collection by G. H. K. Thwaites, whose collections provided ‘many adult examples of both sexes’. Although the original description does not specify the number of specimens examined, it implies there was a good type series present. Unfortunately, only a single male labelled C. insigne remains in NHML. We were unable to locate the female syntype in the collection of NHML and it is presumably lost (see discussion below). The male is accompanied by a label written by Reginald Innes Pocock, who wrote many other type labels in the NHML’s collections ( Figs 2 vs. 8). The label does not provide any indication of the type status. This renders the taxonomic status of the designated female C. insigne even more doubtful. Correct identification can be made only after adults of both sexes are collected at the same time from the type localities, particularly from Sri Lanka and India.

Diagnosis. Cheiracanthium insigne is a distinctive species not likely to be confused with any other. Both the unique prolaterally curved and anteriorly extended tegular flange ( Figs 3 , 6–7 , TF) and the exceptionally elongate, semi-transparent posterior flange on the tegulum ( Figs 4–5 , TF) are diagnostic. Although a projecting cymbial spur on the baso-retrolateral side of the cymbium of C. insigne is relatively small in comparison to other males of Cheiracanthium , it is represented by a short triangular projection pointing posteriorly. The presence of a cymbial spur is one of a few synapomorphies of the genus ( Deeleman-Reinhold 2001; Lotz 2007a). It is crucial in distinguishing between Southeast Asian eutichurines. Deeleman-Reinhold (2001) separated males of Cheiracanthium from those of Calamoneta Deeleman-Reinhold, 2001 by the lack of a cymbial spur in the latter genus. Cheiracanthium is distinguishable from that of Calamopus Deeleman-Reinhold, 2001 in the possession of a cymbial spur that is pointing posteriorly, whereas the spur is flexed at base and pointing in anterior direction in Calamopus species.

Distribution. India, Sri Lanka, Burma, Thailand ( Fig. 18 ).

Figures

FIGURE 18. Records of C. insigne O. P. – Cambridge, 1874.

FIGURES 1 – 4. Cheiracanthium insigne O. P. – Cambridge, 1874, male syntype (1, 3 – 4). 1 Habitus, dorsal. 2 Label accompanying type. 3 – 4 Left male palp (3 ventral, 4 retrolateral).

FIGURES 5 – 9. Cheiracanthium insigne O. P. – Cambridge, 1874 (male holotype of Eutittha gracilipes Thorell, 1895 deposited at NHML). 5 – 7 Left male palp (5 retrolateral, 6 ventral, 7 prolateral). 8 Label accompanying type. 9 Original label of Thorell.