Ero natashae, Sherwood & Henrard & Peters & Price & Hall & White & Grignet & Wilkins, 2024

Sherwood, Danniella, Henrard, Arnaud, Peters, Martina, Price, Benjamin W., Hall, Andie C., White, Oliver W., Grignet, Virginie & Wilkins, Vicky, 2024, Two new sympatric species of the pirate spider genus Ero C. L. Koch, 1836 from the cloud forest of Saint Helena Island, South Atlantic Ocean (Araneae: Mimetidae), European Journal of Taxonomy 921, pp. 76-97 : 89-94

Ero natashae sp. nov.

urn:lsid:zoobank.org:act:DC475BB8-DEBF-41C2-AC9F-9476840FB9B5

Figs 10–13

Ero aphana – Unzicker 1977: 127–129 (misidentification).

Diagnosis

Ero natashae sp. nov. can be distinguished from the male of E. lizae sp. nov. by smaller abdominal tubercles ( Figs 10A–D ) and by the shape of palpal structure, namely: 1) retrolateral cymbial process hooked, thinner and more developed conductor (retrolateral cymbial process non-hooked and conductor wider and less developed in E. lizae ), and 2) lower dorsal triangular extension of paracymbium much smaller (lower dorsal triangular extension significantly larger in E. lizae ). Ero natashae sp. nov. can be differentiated from E. aphana by the blunt hooked retrolateral cymbial process (retrolateral cymbial process more prominently hooked in E. aphana ), and the different shape of the paracymbium and conductor (cf. Figs 10E–F , 11 , 13A–B ). Females can be distinguished from both species by its epigyne ( Figs 12 , 13C–D ) with narrow copulatory openings and a strongly protruding anteromedian plate medially crossed by a thin septum (copulatory openings wider and anteromedian plate slightly protruding and not medially crossed by a thin septum in E. aphana and E. lizae ). Both sexes appear to be smaller in body size and have comparatively longer legs than E. lizae , which serve as secondary taxonomic characteristics that may further separate them, also possibly indicating E. natashae inhabits darker habitats.

Etymology

The specific epithet is a matronym honouring the Saint Helenian conservationist Natasha Stevens ( Saint Helena National Trust) who has spent many years studying and conserving the invertebrates of Saint Helena, and who provided great help and kindness to the senior author during her expedition to the island.

Material examined

Holotype

UNITED KINGDOM – Saint Helena, Ascencion and Tristan da Cunha • ♂; High Central Ridge , Mt Actaeon, Saint Helena; alt. 792–822 m; 11 Dec. 1965; P.L.G. Benoit, P. Basilewsky and N. Leleup leg.; BE_RMCA_ARA.Ara.129326.

Paratypes

UNITED KINGDOM – Saint Helena, Ascencion and Tristan da Cunha • 1 ♂, 1 ♀; High Central Ridge, Cabbage Tree Road , Saint Helena; alt. 701–822 m; 6 Feb. 1967; J. Decelle and N. Leleup leg.; in rotten trunk; BE_RMCA_ARA.Ara.133379 • 1 ♂, 1 imm.; same collection data as for preceding; Mar. 1967; BE_RMCA_ARA.Ara.133305 • 1 ♂; SW of Thompsons Wood , Saint Helena; alt. 518–548 m; 23 Nov. 1965; P.L.G. Benoit, P. Basilewsky and N. Leleup leg.; BE_RMCA_ARA.Ara.129109 • 1 ♂; High Peak, Saint Helena; 15°58′ S, 5°42′ W; alt. 731–792 m; Mar. 1967; J. Decelle and N. Leleup leg.; BE_RMCA_ARA.Ara.133333 .

Description

Male holotype

MEASUREMENTS. Total length including chelicerae: 2.92. Carapace: 1.48 long, 1.28 wide. Ocular tubercle: 0.26 long, 0.70 wide. PLE distinctly projecting over the outer edge of carapace, ALE distinctly projecting over the front of ocular tubercle. Chelicerae with 7 peg teeth. Stridulatory ridges absent. Opisthosoma: 1.45 long, 1.26 wide.

LEGS (femur + patella + tibia + metatarsus + tarsus). I 11.81 (3.59 + 0.80 + 3.56 + 2.56 + 1.30), II 7.49 (2.34 + 0.55 + 2.00 + 1.56 + 1.04), III 4.83 (1.66 + 0.50 + 1.15 + 0.85 + 0.67), IV 6.09 (2.21 + 0.53 + 1.56 + 1.13 + 0.66). Metatarsus I with 5 strong spines.

OPISTHOSOMA. With two pairs of tubercles, anterior pair smaller than posterior pair ( Fig. 10 A–D ).

PALP. Embolus emergent proximally, twisted distally, conductor distally rounded, cymbium with retrolateral process (RP), paracymbium with two dorsal extensions and one ventral blade (VB), upper dorsal extension (UE) with apex somewhat triangular, lower dorsal extension (LE) rounded, ventral blade longer than lower dorsal extension and shorter than upper dorsal extension, apex somewhat triangular ( Figs 10E–F , 11 , 13A–B ).

COLOUR (in alcohol; Figs 10A–D ). Carapace brown, with brown markings on lateral and posterior edges, brown blotches forming broken line medially behind ocular tubercle, and single, broken longitudinal brown line extending entire length of carapace medially; legs annulated; opisthosoma brown with black and cream blotches in posterior half.

Female paratype (BE_ RMCA _ARA.Ara.133379)

MEASUREMENTS. Total length including chelicerae: 3.05. Carapace: 1.72 long, 1.35 wide. Ocular tubercle: 0.30 long, 0.73 wide. PLE distinctly projecting over the outer edge of carapace, ALE distinctly projecting over the ocular tubercle. Chelicerae with 7 peg teeth. Stridulatory ridges absent. Opisthosoma: 2.32 long, 1.87 wide.

LEGS (femur + patella + tibia + metatarsus + tarsus). I 10.17 (3.62 + 0.75 + 2.34 + 2.41 + 1.05), II 7.40 (2.14 + 0.65 + 2.03 + 1.56 + 1.02), III 3.59 (0.85 + 0.56 + 1.21 + 0.54 + 0.43), IV 4.75 (1.58 + 0.59 + 1.53 + 0.72 + 0.33). Metatarsus I with 5 strong spines.

OPISTHOSOMA. With two pairs of tubercles, anterior pair smaller than posterior pair ( Fig. 10D ).

EPIGYNE AND VULVA. Epigyne with very small septum, outer edges of septum weakly sclerotised, curved in anterior two thirds, copulatory openings circular, vulva with two globular spermathecal receptacles ( Figs 12 , 13C–D ).

COLOUR (in alcohol; Fig. 10D ). Carapace brown, with brown markings on lateral and posterior edges, brown blotches forming broken line medially behind ocular tubercle, and single, broken longitudinal brown line extending entire length of carapace medially; legs annulated; opisthosoma brown with black and cream blotches in posterior half.

Distribution

Known only from the Peaks National Park, and southwest of Thompson's Wood, Saint Helena (see Fig. 9D–E ).

Remarks

Ero natashae sp. nov. is sympatric with E. lizae sp. nov. (see above) but is easily distinguished by the absence of large spike-like tubercles and by divergent genital organ morphology. Unlike the latter species, it has never been photographed, and no new specimens have been recorded since 1977. Further fieldwork is required to ascertain the population status of this species, and its habitat preference. Unfortunately, it was impossible to sequence this species molecularly within the timeframe and funding of the present work, especially as no fresh material was available.

Figures

Fig. 10. Ero natashae sp. nov. A–C, E–F. Holotype, ♂ (BE_RMCA_ARA.Ara.129326). D. Paratype, ♀ (BE_RMCA_ARA.Ara.133379). A. Habitus, dorsal view. B. Habitus, lateral view. C. Habitus, posterior view. D. Habitus, lateral view. E. Palp, anterior view. F. Palp, showing the detail of cymbial basolateral extensions, retro-ventral view. Abbreviations: see Material and methods. Scale bars: A–B, D = 1 mm; C = 0.5 mm; E–F = 0.1 mm.

Fig. 11. Ero natashae sp. nov., holotype, ♂ (BE_RMCA_ARA.Ara.129326), palp. A. Prolateral view. B. Idem, slightly dorsal. C. Dorsal view. D. Retrolateral view. E. Idem, slightly ventral. F. Ventral view. Scale bars = 0.2 mm.

Fig. 12. Ero natashae sp. nov., paratype, ♀ (BE_RMCA_ARA.Ara.133379), genitalia. A. Epigyne, ventral view. B. Idem, anterior view. C. Vulva, dorsal view. D. Idem, slightly lateral. Abbreviations: see Material and methods. Scale bars = 0.1 mm.

Fig. 13. Ero natashae sp. nov., genitalia illustrations. A. Holotype, ♂ (BE_RMCA_ARA.Ara.129326), palp, retrolateral view. B. Idem, ventral view. C. Paratype, ♀ (BE_RMCA_ARA.Ara.133379), epigyne, ventral view. D. Vulva, dorsal view. Abbreviations: see Material and methods. Scale bars: A–B = 0.2 mm; C–D = 0.1 mm.

Fig. 9. A–C. Ero lizae sp. nov., non-type, ♀ in vivo. D. Panorama of Peaks showing cloud forest habitat. E. Ground-view from type locality.