A new species of Trite Simon, 1885 (Araneae: Salticidae) from New Zealand, with remarks on Trite relationships and radiation

A species known from earlier behavioural studies as “Holoplatys sp.”, is described as Trite pollardi sp. nov. Within the genus Trite, two species groups are distinguished: the planiceps-group (found in New Caledonia, New Zealand, Lord Howe Island and Norfolk Island) and the incognita-group (limited to New Zealand). The three alternative scenarios of the Trite origin, relationships and radiation in New Zealand, New Caledonia and Lord Howe Island are discussed. Three species are considered to be excluded from Trite.

A spider known as ''Holoplatys sp.'' was subjected to behavioural studies (Jackson & Harding, 1982), but its biology raised some doubts about its generic placement. Instead of being a typical tree trunk and bark dweller (see Żabka, 1991b), ''Holoplatys sp.'' was found in a variety of microhabitats, including vegetation, mainly New Zealand flax (Phorbium tenax: family Asphodelaceae). During MŻ's research in New Zealand in 2000 the opportunity was taken to clarify the case. As suspected, the species was not Holoplatys, but belonged in the genus Trite-well known from New Zealand and other island groups in South West Pacific (Table 1). Further studies revealed many other undescribed species of Trite and inspired us to investigate the genus' origin and relationships.

MATERIAL & METHODS
The specimens for study came from the following collections: Auckland Museum Entomology Collection-AMNZ; Canterbury Museum, Christchurch-CMNZ; Entomology Research Museum, Lincoln-LUNZ; Museum of New Zealand, Wellington-MONZ; New Zealand Arthropod Collection, Auckland-NZAC; Otago Museum, Dunedin-OMNZ. The examination methods were as described by Żabka (1991a). The drawings were made using a grid system. The photographs were taken with Nikon D5200 camera and Nikon SMZ1000 stereomicroscope, and were digitally processed with ZoomBrowser and HeliconFocus software. The actual and predicted distributional maps were generated with DIVA-GIS bio-climatic software using BIOCLIM application (Nix, 1986;Busby, 1991). Our model has been produced with 12 field records and met the requirements for 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, max temperature of warmest month, min temperature of coldest month, temperature annual 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, precipitation of coldest quarter.
The origin and relationships of Trite, were considered in the light of the available morphological and molecular data (Maddison, Bodner & Needham, 2008;Bodner & Maddison, 2012;Maddison, 2015).
The electronic version of this article in Portable Document Format (PDF) will represent a published work according to the International Commission on Zoological Nomenclature (ICZN), and hence the new names contained in the electronic version are effectively published under that Code from the electronic edition alone. This published work and the nomenclatural acts it contains have been registered in ZooBank, the online registration system for the ICZN. The ZooBank LSIDs (Life Science Identifiers) can be resolved and the associated information viewed through any standard web browser by appending the LSID to the prefix http://zoobank.org/. The LSID for this publication is: urn:lsid:zoobank.org:pub:EC2FDD31-400F-4221-A96C-D48E1BDB684A. The online version of this work is archived and available from the following digital repositories: PeerJ, PubMed Central and CLOCKSS.

Remarks on relationships and radiation
Of the 18 nominal species of Trite (World Spider Catalog, 2017) (Table 1), three are non congeneric, two of them T. ignipilosa and T. rapaensis requires type material and their generic placement will be decided in separate paper, while ''T. auricoma'' and related (undescribed) species are another example of intense radiation in New Zealand; for all of them a new genus should be established. Others occur in New Zealand (5 spp.), New Caledonia (5 spp.), Lord Howe Island (2 spp.) and on smaller island groups (Żabka, 1988;Berry, Beatty & Prószyński, 1997;Patoleta, 2002;Patoleta, 2014;Richardson, 2016). According to molecular data, the genus Trite is part of the Australasian Astioida clade and Vicirini tribe, the latter being dominated by Australian and New Caledonian genera (Maddison, Bodner & Needham, 2008;Maddison, 2015). The whole Astioida clade arose ∼30 MYA, while the genus Trite is ∼10 MYA (T. pennata from New Caledonia and T. planiceps Simon, 1899 from New Zealand) ( Fig. 1) (Bodner & Maddison, 2012;Zhang & Maddison, 2013). The analysis of genitalic structures in Trite allowed us to distinguish two species groups .
In the planiceps-group  the male palpal tegulum is narrow, about the width of the cymbium, without or with a small tegular lobe. The female epigyne  is not especially elongate, and without a caudal lobe. The internal genitalia are close to the epigastric furrow, the insemination ducts distinctive and spermathecae ovoid or pear-shaped. The group is found in New Caledonia, New Zealand, Lord Howe Island and Norfolk Island.
In the incognita-group (Figs. 5 and 9) the tegulum is robust (trapezoid), wider than the cymbium and with a distinctive lobe (tl). The epigyne is elongate, with a caudal lobe (cl). The internal genitalia are distant from the epigastric furrow, spermathecae are large and pear-shaped and insemination ducts are almost missing. Particular species within the group differ in tiny details proving they are the result of a very recent radiation. We consider this pattern more derived. The group is limited to New Zealand (Fig. 10).
To discuss the history of Trite, it is necessary to consider geological and climatic circumstances for the area of Trite occurrence.
Until quite recently, the nature of New Zealand and New Caledonia was often discussed in terms of Gondwanan heritage, but geological data show much greater complexity and are only partly supportive of this view. After separation from Gondwana (∼85 MYA), both island groups (New Zealand and New Caledonia) were part of the Zealandia land mass (e.g., Cluzel et al., 2012;Campbell et al., 2012). Since the late Cretaceous, New Caledonia has experienced many episodes of subduction and submergence and emerged only in post-Eocene, 37 MYA (Cluzel et al., 2012). The fate of New Zealand was even more dramatic (Campbell et al., 2012;Sharma & Wheeler, 2013). The interactions between the Pacific and Australian plates (30 MYA) initiated multiple submergences of large parts (but possibly not all) of New Zealand (Mildenhall et al., 2014). Over the last 5 MY, the events intensified (Cox & Findlay, 1995;Batt et al., 2000), resulting in the uplift of the Southern Alps and severe Pleistocene climate changes. All these circumstances might have caused multiple extinctions and stimulated speciation and local radiations. Given the timing proposed by Bodner & Maddison (2012), the salticid fauna of both island groups should be considered as the result of (1) colonisations from other sources, mainly from Australia over the last 30 MY and (2) local radiation.
Lord Howe Island is located on the submerged Lord Howe Rise (Mortimer et al., 2017), which links the island to New Caledonia. The present Lord Howe Island is dated as 7 MYA-old enough to develop some endemic species, but too young and small (18.576 km 2 ) to expect a high diversity of biota and higher-level endemic taxa (genera). The Lord Howe Island salticids probably derived from Australian and New Caledonia ancestors, which reached the islands by dispersal.    The above circumstances allow us to propose three alternative scenarios for Trite radiation.
1. New Caledonia as the origin for Trite: strongly supported by the presence of planiceps-group of species, but, first of all, by several related astioid genera (Corambis Simon, 1901, Penionomus Simon, 1903, Rhondes Simon, 1901, Lystrocteisa Simon, 1884, Rogmocrypta Simon, 1900, all endemic for New Caledonia with relatives (sister genera?) in Australia (Patoleta, 2002;Patoleta, 2017;Bodner & Maddison, 2012). Under this scenario the first New Caledonia Astoida arrived from Australia some 30 MYA. The genus Trite appeared ∼10 MYA, radiated within the planiceps-group and spread to New Zealand (T. planiceps, T. pennata). The species in Lord Howe Island, Norfolk or other islands would be the result of dispersal and radiation in situ.
2. New Zealand as the origin: supported by far the largest number of species in both groups and the incognita-group being limited to New Zealand. However, the lack of ancestral (related) genera makes this scenario less likely. The diversity within the incognitagroup suggests recent local radiation within the last 5 MY. Such a possibility is also supported by New Zealand Lycosidae (Vink & Paterson, 2003) and Thomisidae (Sirvid et al., 2013).
3. Australia as the source of Trite ancestors: supported by the similarities in genitalic structures between the planiceps-group and some Australian genera (Pungalina Richardson, 2013) (Richardson, 2013;Richardson, 2016).
Diagnosis. Differs from other species of Trite by the following combination of characters: body flat (Holoplatys-like), lighter abdominal colour pattern, palpal organ with a distinctive tegular lobe, cymbium with protuberance, epigyne caudal lobe with median incision, copulatory openings accompanied by sclerotized crevice, fertilization ducts narrow, close to the epigastric fold.
Biology. The species is usually found on New Zealand flax (Fig. 13) and tussock grass, but also occasionally under rocks, in crevices of driftwood and under manuka bark (Leptospermum scoparium: family Myrtaceae). Trite pollardi has large repertoire mating behaviours (Jackson & Harding, 1982). Distribution (Fig. 14). The species has been recorded all over the North and South Islands of New Zealand.

Abbreviations AEW
Anterior eye width ag Accessory gland AME Anterior