Argiope hoiseni, Tan, 2018

Tan, Ji, 2018, Argiope hoiseni, a new species of the spider genus Argiope (Araneae, Araneidae) from Peninsular Malaysia based on morphology and molecular analyses, Zootaxa 4457 (1), pp. 129-142 : 133-136

Argiope hoiseni new species

Figs. 1–12

Type material. Holotype female (UIR 181014 - AHOI1 ): PENINSULAR MALAYSIA: Selangor, Ulu Yam, near Sungai Tua waterfall (03°19'52.17"N, 101°42'7.16"E), collected 18 October 2014, Tan J. (deposited in the arachnid collection of UTAR Insect Repository (UIR), Kampar , Perak, Malaysia). Paratypes (same locality as holotype): 18 October 2015, Tan J., 3 females (UIR 181015 - AHOI3 , 4 , 5 ) . PENINSULAR MALAYSIA: Perak, Kampar, near Sungai Salu waterfall (04°20'32.86"N, 101°11'31.80"E), 4 August 2015, Tan J., 1 female (UIR 040815 - AHOI2 ) .

Etymology. The species epithet is dedicated to Prof. Emeritus Dr. Yong Hoi Sen for his vast contributions in the fields of arachnology and entomology in Malaysia.

Diagnosis. The relatively small sizes (<8.2 mm body length) of mature female individuals as well as their unique, dull-colored dorsal opisthosoma with two anterolateral humps and multiple horizontally interspersed black spots ( Fig. 4 ) separate this species from all other small-sized and showy Argiope , i.e., A. buehleri , A. bullocki Rainbow 1908 , A. caledonia Levi, 1983 , A. chloreis , A. doboensis , A. kochi Levi, 1983 , A. mascodi Levi, 1983 , A. minuta Karsch, 1879 , A. niasensis , A. ocyaloides L. Koch, 1871 , A. perforata Schenkel, 1963 , A. takum Chrysanthus, 1971 and A. truk Levi, 1983 . In terms of epigynal structure, A. hoiseni bears some resemblance to A. jinghongensis (Figs. 95-107 in Jäger 2012), A. luzona (Figs. 227–231 in Levi 1983), A. pulchella (Figs. 238–247 in Levi 1983), and A. taprobranica (Figs. 222–226 in Levi 1983) of the A. aetherea species group characterized by a relatively narrow epigynal rim and septum that extends into a prominent and protruding posterior plate in ventral view. However, this species but can be differentiated based on (i) the ventrally flat epigynum with a relatively thick rim and (ii) septum that broadens into a posterior plate with rounded edges in ventral view and with a median indentation in posteroventral view ( Fig. 9 ).

Description. Female (holotype; male unknown). PL 3.1, PW 2.8, OL 4.3, OW 4.2. Eye diameters and interdistances: AME 0.14, ALE 0.10, PME 0.18, PLE 0.14, AME-AME 0.13, AME-ALE 0.30, PME-PME 0.20, PME-PLE 0.31, AME-PME 0.31, ALE-PLE 0.01, clypeus AME 0.15, clypeus ALE 0.10. Leg and pedipalps measurement: pedipalps 2.9 (1.0, 0.4, 0.5, -, 1.0), leg I 15.6 (4.1, 1.5, 3.3, 5.5, 1.2), leg II 14.3 (4.1, 1.7, 3.2, 4.1, 1.2), leg III 7.7 (2.8, 0.9, 1.4, 1.8, 0.8), leg IV 13.2 (4.4, 1.3, 2.6, 3.8, 1.1). Leg formula 1243. Chelicerae length 1.1, 3 anterior teeth, 4 posterior teeth; palpal claw with 8 teeth.

Female genitalia ( Figs. 8–12 ): Epigynum wide in ventral view, angular in lateral view, with a wide and relatively thick rim that curves posteriorly. Septum narrow and broadens into a posterior plate with rounded edges in ventral view and with a median indentation in posteroventral view, the continuation of posterior plate extends dorsally and fills the depressions almost completely. Openings more visible in posteroventral and ventrolateral views. Spermathecae elongated oval, somewhat parallel; fertilization ducts folded and originate posteriorly.

Somatic morphology. Carapace brown and thoroughly covered with dense greyish setae, partly radial markings, fovea indistinct. Sternum pale yellow with darker borders, with three pairs of lateral humps and one less conspicuous posterior hump, anterolateral humps dark brown ( Fig 7 ). Labium, maxilla and chelicerae pale brown. Coxae I–II pale brown, partly with small black patches, Coxa III black, coxa IV mostly pale brown. Legs densely hirsute with alternating bands of pale and dark brown, orderly arranged dark spots at base of most leg spines, numerous short spines on proximal segments and long spines at distal segments; spines mostly pale brown with black base or entirely black; ventral black patches on femur and patella I–IV, proximal tibia and distal metatarsus brighter. Dorsal opisthosoma yellowish brown with multiple horizontally interspersed black spots, becoming darker posteriorly, anterolateral humps pale yellow, sigilla black; ventrally strikingly marked with black and white bands and six white spots, surrounded by yellowish white longitudinal bands; spinnerets brown ( Fig. 2 ).

Variation. The body length of all specimens ranges between 5.7 mm and 8.2 mm (n= 5). The examination of other paratypes indicate a color variation between individuals, ranging from brown to yellowish-brown.

Distribution. Known only from type localities of Perak and Selangor, Peninsular Malaysia.

Natural history. Specimens were found near rivers in disturbed forests. Adult females built tiny webs (~ 20– 30 cm in diameter) with linear-type stabilimenta at elevations of at least two meters above ground- a phenomenon not generally observed in other Argiope species. Webs were generally built close (<3 cm) to a vertical plane e.g. tree trunk (n= 1) or sign board (n= 4). Egg sacs conical with a somewhat hexagonal base. Younger females appeared to display more vibrant yellow color that likely fades with age. Males not observed. The breeding season of the species is likely between August to January when rain is abundant in the peninsula.

Genetic Analyses. The 16S, COI, COII and H3A DNA markers were successfully amplified and sequenced for all specimens ( Table 1). Similar results were obtained for the nuclear 18S marker with the exception of Argiope pulchella APUL1 which failed to yield any DNA amplification. The final DNA alignment lengths of the 16S, COI, COII, H3A and 18S markers were 461 bp, 521 bp, 414 bp, 336 bp and 874 bp, respectively. The data partitions and substitution models used for phylogenetic inference are summarized in Table 2. The 16S+COI+COII+H3A+18S phylogenetic tree ( Fig. 13 ) best represented the phylogeny of Argiope and is discussed here. Also included is the COI+COII+H3A tree ( Fig. 14 ) which incorporated relevant DNA sequences from GenBank ( Table 1). Other trees (16S, COI, COII, COI+COII and 16S+COI+COII+H3A etc.) are available upon request. All phylogenetic trees displayed similar topology– a clear delineation between Argiopinae and the outgroups of Cyrtophora and Gasteracantha .

Based on the 16S+COI+COII+H3A+18S tree ( Fig. 13 ), Argiopinae was inferred to be monophyletic (BS 97 %, PP 1.00) with Neogea nocticolor sister to all remaining taxa. Gea spinipes was shown to be paraphyletic with respect to Argiope (BS 65 %, PP 0.95). This phenomenon was observed in all concatenated datasets used in this study, although the precise evolutionary lineage of the species was unresolved.

Argiope aemula was sister to the remaining Argiope species which were divided into two major clades A and B (BS 73 %, PP 0.70). Clade A (BS 73 %, PP 0.70) was comprised of subclades A1 ( A. hoiseni , A. pulchella , A. versicolor and A. jinghongensis ) (BS 83 %, PP 0.96) and A2 ( A. dang , A. mangal and A. modesta ) (BS 92 %, PP 1.00). Argiope hoiseni and A. pulchella APUL1 were inferred to be sister to each other (BS 99 %, PP 1.00), and all A. hoiseni specimens were monophyletic (ML = 99.6 %; BI = 1.00). Genetic variation was apparent in A. hoiseni despite specimens being mostly collected from the state of Selangor, Peninsular Malaysia. Clade B (BS 51 %, PP 0.68) which consists of A. chloreis , A. reinwardti and A. doleschalli was poorly resolved.

The COI+COII+H3A phylogenetic tree ( Fig. 14 ) incorporated Argiope GenBank DNA sequences from Southeast Asia. The topology of the inferred tree was similar to that of the previous tree but with generally lower nodal supports. Notable differences include: (i) A. doleschalli as the basal group of the Argiope ingroup and (ii) the clustering of A. aemula , A. catenulata , A. chloreis and Gea spinipes in a poorly supported clade. It is worth mentioning that the COII tree (available upon request) suggested some genetic relation between A. hoiseni and an A. luzona (GenBank accession GU353224 ) from the Philippines.

The uncorrected “p” distance (%) between selected, representative samples of selected Arigope species based on the 16S+COI+COII+H3A dataset is summarized in Table 3. All values of genetic distance used hereafter are based on this dataset unless stated otherwise. A genetic distance (GD) of 5.22–5.97 % was recorded between A. hoiseni and A. pulchella . The genetic difference between A. hoiseni and A. jinghongensis was 4.87–5.91 %. The intraspecific variation between A. hoiseni specimens collected in the present study was 0.87–3.59 %.

Figures

FIGURE 13. Bayesian tree based on the concatenated 16S+COI+COII+H3A+18S dataset of samples used in this study. Numeric values at nodes arranged in an order of Ultrafast ML bootstrap support ǀ Bayesian posterior probability. Abbreviations: CB, Cambodia; ID, Indonesia; MY, Malaysia; SG, Singapore.

FIGURE 14. Bayesian tree based on the concatenated COI+COII+H3A dataset including GenBank sequences. Numeric values at nodes arranged in an order of Ultrafast ML bootstrap support ǀ Bayesian posterior probability. Abbreviations: CB, Cambodia; ID, Indonesia; MY, Malaysia; SG, Singapore.

FIGURES 1–5. Argiope hoiseni n. sp. 1, Dorsal view of holotype female (UIR181018-AHOI1) and linear-type web stabilimentum. 2, Ventral view. 3, Egg sac. 4, Gravid female (paratype UIR081216-AHOI4) in resting position. 5, Young female cleaning its fangs (paratype UIR040815-AHOI2).

FIGURES 6–12. Argiope hoiseni n. sp., female. 6, Dorsal habitus. 7, Ventral habitus. 8, Epigynum, ventral view. 9, Posteroventral view. 10, Lateral view. 11, Posterior view showing copulatory openings (arrows). 12, Dorsal view. Abbreviations: FD, fertilization duct. Scale bars, 6–7, 1mm; 8–12, 0.1mm.