High Tide or Low Tide ” : Desis bobmarleyi sp . n . , a new spider from coral reefs in Australia ’ s Sunshine State and its relative from Sāmoa ( Araneae , Desidae , Desis )

Spiders of the genus Desis Walckenaer, 1837 (Araneae: Desidae) are water-adapted spiders and live in the intertidal zone on reefs, marine debris and under rocks. Here, we describe a new intertidal species from tropical Queensland and name it after Bob Marley, whose song “High Tide or Low Tide” inspired us as it lives in a “high tide low tide” habitat. We also re-describe a close morphological relative, Desis vorax L. Koch, 1872 from Sāmoa. This species was described some 150 years ago from the Godeffroy Collection which holds the oldest major collection of Australasian and Pacific spiders, now mainly hosted in the Centre of Natural History in Hamburg (CeNak). A third species, Desis hartmeyeri Simon, 1909, was described from juvenile specimens only and is considered a nomen dubium. “None but ourselves can free our minds.” Bob Marley, Redemption Song (1980).


Introduction
When Amalie Dietrich travelled from Europe to Australia in 1863 she not only attempted to collect animals and plants for the museum trade, but also sought independence and liberty.A strong-headed and adventurous women by nature, she seized new opportunities and took risks on a then-unexplored continent to elevate herself from poverty and oppression.Her life story is that of adventure and also life's struggles and how to overcome them (Bischoff 1931).The Godeffroy Collection of arachnids, accumulated by her and other explorers over a decade in Australia and the Pacific before the turn of the 20 th century, is the primary taxonomic reference for spiders of Australasia and remains highly relevant until today (Weidner 1959(Weidner , 1967)).
Reggae legend Bob Marley certainly had a different background but shared with Dietrich and other explorers some character traits: adventurous and resilient at heart, he liberated himself and his peers from poverty and hopelessness.He took to music, not nature, but left traces through songs that teach optimism and independence of the mind, rather than hate and passive endurance.The song 'High Tide or Low Tide' promotes love and friendship through all struggles of life.It is his music that aided a field trip to Port Douglas in coastal Queensland, Australia, to collect spiders with a highly unique biology.
Intertidal spiders of the genus Desis have a remarkable biology in that they are truly marine animals (Mcqueen and McLay 1983;Mcqueen et al. 1983).The known species hide away in barnacle shells, corals or the holdfasts of kelp during high tide where they built air chambers from silk, but are vagrant hunters of other invertebrates during low tide and typically collected from the surface of intertidal rocks, corals, debris or plants (Mcqueen andMcLay 1983, Vink et al. 2017).Some other spider families, such as Paratheuma in the family Dictynidae (Beatty and Berry 1988), share a similar biology but overall this is a rare pattern amongst spiders that are otherwise terrestrial animals.
It is the unique Godeffroy Collection of Australian and Pacific spiders at the Centre of Natural History in Hamburg, which contains almost all of the spiders collected by Amalie Dietrich, and also the first desid to be described from this part of the world.Three species were described in 1872 as part of the first major monograph on Australian spiders "Die Arachniden Australiens" which was compiled for more than a decade by distinguished arachnologists Ludwig Koch and Duke Eduard von Keyserling (Koch andKeyserling 1871-1883).Both arachnologists received the material from the Godeffroy Museum for taxonomic research and the desids were originally collected from Singapore, New Guinea and Sāmoa.Soon after, additional specimens were collected from Australia (Hector 1877, Pocock 1902) but surprisingly little is still known about the distribution and richness of these interesting spiders along the vast coastlines of this continent (ALA 2017;Framenau et al. 2014;Paquin et al. 2010;Whyte and Anderson 2017).Two species are currently known from Australia: Desis hartmeyeri Simon, 1909 from Albany in southwestern Australia and D. kenyonae Pocock, 1902 from south-eastern Australia in Victoria and Tasmania (World Spider Catalog 2017, Framenau et al. 2014).However, at least D. hartmeyeri is an enigmatic species and no faunistic or taxonomic entries were made since the time of the original description (Simon 1909).
The present paper revisits some of the intertidal species of Desis in Australia by re-examination of material of the Godeffroy Collection, but also details the discovery of a new species from Port Douglas near Cairns in Queensland.The new species was identified during a collecting trip along the coastline of Australia's, "Sunshine State" (Fig. 2B).Two adult Desis specimens (Figs 1, 2D) were found on brain coral (Fig. 2C) at extremely low tide on a reef that is at high tide often more than 3 m under water (Fig. 2A).The male of this new Australian species is similar to Desis vorax found in the Collection of CeNak.This species was described as a single specimen from Sāmoa more than 150 years ago but has not been recorded or properly illustrated since.
In this paper we describe Bob Marley's, intertidal spider from Queensland, a species that can live in "High Tide or Low Tide" of extreme habitat, and clarify the status of two other poorly-known species, one from the Godeffroy Collection and a second from south-western Australia, both deposited in CeNak, through detailed re-examinations of the specimens used for the original descriptions.Both species have been preserved for more than a century but not been studied in detail since their discovery.By doing so, we honour those that emancipate themselves from oppression, mental or organisational, and seek freedom and independence.7A, B).Females of Desis bobmarleyi sp.n. share the long convoluted copulatory ducts but have them arranged spherical not longitudinal (Fig. 7D).
Distribution.Known from intertidal zones of the Great Barrier Reef at the north-eastern coast of Queensland: Australia's "Sunshine State".The exact distribution range along the coastline of Australia is still unknown.Harvey 1992) and the four juveniles are deposited at three museums: one in Hamburg, two in Berlin and one in Perth.Simon (1909) did not designate a holotype and all four specimens are treated here as syntypes.The identification of species in morphologically conserved groups of spiders, such as Desidae, inevitably requires adult specimens and D. hartmeyeri cannot be reliably identified based on these specimens and may be synonymous with some of the other Australian species for which adult specimens are available.No additional information on this species -biological, distributional or taxonomic -is available that could elucidate its status.The collection locality is geographically distinct (all other records are from eastern Australia) but many Desis species have wide ranges and the specific habitat is not strongly distinct from any such habitats in south-eastern Australia.The purpose of a species description is to facilitate species identification but this is not possible from the data available and the specific name adds to taxonomic redundancy in this group of spiders.This species is a nomen dubium.
Diagnoses.Males of D. vorax can be separated from other Desis species, including D. bobmarleyi, D. marina and D. kenyonae, by having a slim, triangular conductor plate (CP) and a slender conductor tip (Fig. 7F).
Distribution.Currently known only from Upolu, one of the islands of the Independent State of Sāmoa.The wider distribution of this species is still unknown but it may be more widespread across the islands of Sāmoa.
Remarks.Apparently, this species has not been recollected since its original discovery but may have been overlooked because it is found in habitats that are not usually associated with spiders.

Discussion
Biology of Desis bobmarleyi sp.n.
The first specimens were recorded in northern Queensland in the 1970s and early 1980s from specimens that were active during the day amongst intertidal rocks that were exposed only at low tide.Further observations were made on flat reefs and in a lagoon where the spiders were found under loose live and dead corals (Acropora sp.).A thin film of silk was noted in the concavity of the underside of the coral and these may have been remains of the silken retreats during high tide.The spiders were within 20 m of the shoreline and the area would be flooded up to 3 m during high tide.Recently, Mr Paul Hoye, then of the Cairns Municipal Council, brought to our attention a population at Port Douglas north of Cairns.The spiders were found on an inshore reef, about 600 m from shore.Mr Hoye noted that he was only able to find the spiders because the tide was exceptionally low.By searching at such a low tide, two of the authors (RJR, BB) were able to confirm the sighting and take a male and female that were active at a very low tide on 11 January 2009 at night at 2am.

The Godeffroy Collection of spiders
Historical taxonomic collections provide the reference and context for current biodiversity studies, in particular if they are rich in type specimens.The Godeffroy Collection of arachnids at the CeNak is an important historical source and comprises several hundred type specimens of arachnids from all over the world, including more than 450 types from Australia and the Pacific Islands (Weidner 1959).It is the legacy of Amalie Dietrich, an emancipated woman of remarkable independence, that has been preserved for more than 150 years, although many other adventurers and explorers have contributed to this collection.Compiled on behalf of Johann Cesar VI Godeffroy for his private Museum Godeffroy in Hamburg from 1861 to 1885, this is arguably the oldest major collection of arachnids from Australia and still one of the primary taxonomic resources for their study in this region.The current study is another example, amongst others (e.g.Baehr et al. 2017), that highlights the essential character of this collection for present-day taxonomy.

Towards a stable taxonomy for Desis species
There is currently no taxonomic revision for the worldwide-distributed spiders of the genus Desis, which are found on the reefs along many coastlines around the world.
All species within this genus that are known from both sexes share a similar morphology of the male and female genitalia but are also very conserved at the somatic level and appear to be closely related at the morphological level.
The similarities between most described species and the relatively low species numbers (13 species are currently recognised worldwide) may be caused by the specifics of the marine habitat that allows for dispersal across wide distances, but may also indicate ecological constrains that lead to morphological similarity.At least some species appear to have wide ranges and may disperse across wide distances within the aquatic habitat, such as Desis marina (Vink et al. 2017).Some species may be global tramps that have a very wide distribution but, due to their unique biology, often go unnoticed.Others are clearly habitat specialists that may be more tightly restricted but their biology is still poorly known, e.g.Desis kenyonae (Hickman 1967) that has been collected from seaweed in south-eastern Australia and may be restricted to the cool waters near the Bass Strait and Tasmania.
A detailed molecular analysis of all Desis species, including more detailed analyses of spatial distributions and molecular data, is suggested here to test for dispersal capacities, species boundaries beyond morphology, and ecological speciation scenarios rather than vicariance that is generally evoked as a cause for speciation scenarios in terrestrial spiders.In this context, we also notice that the SEM image of Desis formidabilis (Griswold et al. 2005) (Fig. 7G) from South Africa shows a very similar pedipalp structure to Desis bobmarleyi sp.n. from Queensland and Desis vorax from Sāmoa, although there are notable small differences in pedipalp spination and the shape of the CP and MA.These species are closely-related at the morphological level but genetic analyses may show a very different pattern of divergence across the Indian Ocean.Overall, the current study is an essential prerequisite towards a comprehensive taxonomic treatment of Desis at both, the species-and genus level because it illustrates morphological key characters and type specimens, eliminates some of the taxonomic difficulties arising from old descriptions, and adds some basic biological information on the Australian and Pacific fauna.