Salticidae (Arachnida: Araneae) of New Caledonia: Genus Corambis Simon, 1901

The genus Corambis Simon, 1901 includes five species; three of them, C. jacknicholsoni sp. nov., C. logunovi sp. nov. and C. pantherae sp. nov., are described here as new. The female of the C. foeldvarii Szűts, 2002 is described for the first time and a new generic diagnosis is proposed. The distribution and relationships of Corambis are discussed in terms of the geological and bioclimatic history of New Caledonia.


Introduction
New Caledonia (NC) is known for its highly diverse and endemic fauna and is one of the global biodiversity hotspots (Grandcolas et al. 2008;Heads 2010;Wulff et al. 2013). This also applies to spiders. According to WSC (2019), about 300 species are recorded from the archipelago. Given the area of NC (18 576 km 2 ), the number is quite substantial, although it certainly is underestimated, as only a few comprehensive investigations have been carried out there in modern times (Platnick & Forster 1989, 1993Platnick 1993;Raven 1994).

Material and methods
This paper is based on specimens deposited in the collections listed below. The drawings were made using a grid system. The dissected epigynes were digested in 10% KOH, stained in Chlorazol Black E and studied under a transmission microscope. Dimensions (in mm) were measured with MultiScan software. Photographs were taken with a Nikon D5200 camera and a Nikon SMZ1000 stereo microscope, and digitally processed with ZoomBrowser and HeliconFocus software. Scales on figures are in mm.
The actual and predicted distributional maps were generated with DIVA-GIS bio-climatic software. Our model was based on 34 field records and met the requirements of the software (at least 5-10 records; Hernandez et al. 2006). The following environmental variables were used in the analysis: annual mean temperature, mean monthly temperature range, isothermality, temperature seasonality, maximum temperature of warmest month, minimum temperature of coldest month, annual temperature range, mean temperature of wettest quarter, mean temperature of driest quarter, mean temperature of warmest quarter, mean temperature of coldest quarter, annual precipitation, precipitation of wettest month, precipitation of driest month, precipitation seasonality, precipitation of wettest quarter, precipitation of driest quarter, precipitation of warmest quarter and precipitation of coldest quarter. Genus Corambis Simon, 1901Corambis Simon, 1901. -Berland 1924: 247. -Szűts 2002, figs 1-4.

Distribution
All species of Corambis are exclusively distributed in NC and the neighboring Loyalty Islands (Figs 9-10), and are found in different types of forests. The endemic character of the genus is supported by its DIVA-GIS predicted distribution (Fig. 11). This modeling shows that Corambis is limited to NC. (Simon, 1880) Figs 2, 9

Diagnosis
Differs from other species of the genus by its slightly pointed palpal tibial apophysis, posteriorly oriented female copulatory openings and the lateral location of its accessory glands (Fig. 3).  brownish, patellae with dorsal fringe. Other legs light grey, delicate, not distinctive. Epigyne poorly sclerotized, copulatory openings oriented posteriorly. In comparison to other species, insemination ducts wide and longest. Spermathecae two-chambered (Fig. 3H-J

Diagnosis
Differs from other species of the genus by its hook-like embolus (Fig. 4E-F) and the lateral location of ag2 in females (Fig. 5G).

Etymology
This beautiful spider is named for Mr. Jack Nicholson, the great American actor, three times Oscar winner.

Diagnosis
Differs from other species of the genus by its darker coloration, legs with no fringe, longer chelicerae, and much wider and heavier embolus (Fig. 6E-F). Copulatory openings oriented antero-laterally, accessory glands situated posteriorly on spermathecae (Fig. 7G).

Etymology
This species is named for Dr. Dmitri Logunov, a distinctive Russian arachnologist (now at the University of Manchester), a friend of ours. legs dirty light brown, with very strong spines on tibiae and metatarsi. Other legs dirty-orange. Abdomen dirty-orange with distinctive dark spots. Spinnerets grey. Venter light grey, distally darker with two longitudinal lines. Internal genitalia similar to those of C. insignipes, copulatory openings oriented laterally, insemination ducts short, joinings posterior parts of spermathecae. Spermathecae relatively smaller than in C. insignipes, two-chambered ( Fig. 8E-G

Discussion
For a long time the salticids of New Caledonia have been discussed in terms of Gondwanan origin and heritage; however, the timing of NC separation (80 mya), its subsequent submergences and the predicted   age of Salticidae (50 my) make the Gondwanan hypothesis very unlikely. Recent geological studies have revealed that NC was part of the Zealandia land mass, together with New Zealand, Norfolk Island and Lord Howe Island. NC only emerged in the Oligocene, some 37 mya (e.g., Cluzel et al. 2012;Campbell et al. 2012). Under such a scenario the fauna of NC must be much younger than thought before, and its diversity and endemism seem to be the result of 1) later (post-Gondwanan) colonization and dispersal from Australia, and migration between NC, Lord Howe Island and New Zealand, and 2) subsequent radiation in situ. Such a view is strongly supported by the molecular data on the relationships of the Australasian salticid taxa (Maddison et al. 2008;Maddison 2015) and by the case of Trite described earlier (Patoleta & Żabka 2017).
Furthermore, the endemism of Corambis and its relatives (Lystrocteisa, Penionomus, Rhondes, and Rogmocrypta) seems to be the result of quite recent New Caledonian radiation. The timing of this phenomenon is as yet unknown, but judging from the case of Trite and estimates for Penionomus (Bodner & Maddison 2012;Patoleta & Żabka 2017) the radiation may have begun some 10 mya. The problem can be solved by using fresh material and molecular data (molecular clock).