Bianor

• 1. Introduction

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  George and Elizabeth Peckham named Bianor in 1886, reaching back to ancient myth for the label. The name honored a figure also known as Ocnus. These are jumping spiders, small visual hunters that track and pounce rather than spin webs and wait. The Peckhams presumably found something in them worth a classical reference. What makes Bianor distinctive? How far across the globe has the genus managed to spread? And what happened when a researcher returned to the group more than a century later and reconstructed its boundaries from scratch?

• 2. Built for Recognition

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  Males of Bianor announce themselves instantly. The femora, patellae, and tibiae of the first pair of legs are swollen, far more robust than the segments that follow. The body as a whole is compact, shiny, and robust. Females carry orange legs where the males have enlarged ones.

  In size, these spiders typically reach 3 to 4 mm, though the full range across the genus runs from 2 to 7 mm. The carapace sits moderately high, flat on top, with very steep sides. The thorax slopes steadily toward the posterior margin. Dark brown covers the surface, with white hairs scattered across the posterior and lateral portions. In shape, the carapace is a little longer than wide, with rounded sides contracted equally at front and back. Its width never exceeds the breadth of the dorsal row of eyes.

  Below sits an oval abdomen, pale brown and narrower than the carapace, coming to a slight point at the rear. Some individuals carry two or three pairs of large circular tufts of light-colored hairs on the abdomen's surface. The legs are sturdy without being long, with all four pairs running to roughly equal lengths. Ventral spines line the tibiae and metatarsi of the first leg pair, with a few more appearing elsewhere. Color and pattern vary noticeably from one species to the next, a diversity that becomes apparent once the full geographic spread of the genus is laid out.

• 3. Range and Reach

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  The genus has a noted northerly distribution, concentrated in South and Southeast Asia. Species are recorded from India and Sri Lanka in the south, through China and Japan, and across the island chains to Indonesia. Some species extend into Africa. Others are found in Oceania. Two species, Bianor biocellosus and Bianor fasciatus, are known only from Brazil, making South America the genus's most distant outpost.

  Collectors find these spiders living actively among plants. Some specimens were collected near the base of plants at ground level. Others turned up in the canopy of tall trees. That vertical span, from soil surface to the upper canopy, gives the genus access to a wide band of plant-based habitats.

  Bianor simplex, first described by Blackwall in 1865, lives in Cape Verde. Bianor vitiensis was described from Fiji in 1996 by Berry, Beatty, and Proszynski. Bianor compactus, named by Urquhart in 1885, is found in New Zealand. Those island records, in the Atlantic and the South Pacific, mark the furthest confirmed edges of the genus's range.

• 4. A Genus Redrawn

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  Logunov's 2001 revision of Bianor reorganized the genus completely. A new genus, Sibianor, was established during that work to accommodate species that no longer fit within the revised definition of Bianor. Species previously grouped with Bianor were moved into Sibianor.

  Logunov also formally named several new species in that revision. Bianor kovaczi was placed in Ivory Coast, Ethiopia, and Botswana. Bianor murphyi was anchored to Kenya. Bianor punjabicus covered Afghanistan, Pakistan, and India. Bianor senegalensis was assigned to Senegal. Bianor wunderlichi was described from the Canary Islands and the Azores. The type species, Bianor maculatus, had first been described by Keyserling in 1883. As of the most recent count, the genus holds 27 recognized species.

  Two of those, Bianor paulyi and Bianor eximius, were named as recently as 2009. Paulyi came from Madagascar and the Comoros; eximius was found in Zimbabwe, Mozambique, and South Africa. Those additions, coming eight years after Logunov's revision, suggest that the tally of 27 species will not hold unchanged indefinitely.