segunda-feira, 28 de novembro de 2011

Goodbye Azores part 2: spiders, what else?

After the first seven months in the Azores my job was little more than fieldwork logistical tasks. After the sorting of samples belonging to the BALA II project commenced, I was finally getting in touch with the native fauna on the microscope, and soon realized that the diversity was so small that nearly all Azorean endemics and native spider species could be easily recognized and distinguished from each other.
In the field, it is similarly easy to distinguish the few Azorean endemics. At canopy level (bear in mind that I only refer to samples made in native laurel forest) you find Savigniorrhipis acoreensis (Linyphiidae), Rugathodes acoreensis (Theridiidae), Sancus acoreensis (Tetragnathidae), Gibbaranea occidentalis (Araneidae), Lasaeola oceanica (Theriidae) and Acorigone acoreensis (Linyphiidae), all of them, even the tiny ones, being sufficiently different to be distinguished in the field. Just above ground level in exposed areas, you can find the nursery webs of Pisaura acoreensis, the largest endemic spider of the archipelago, especially between July and September. At ground level, several cryptic endemic species are not so easily found, like the erigonines Porrhomma borgesi, Walckenaeria grandis or Minicia floresensis, the later of which can also be found at canopy level sometimes. The small jumping spider Neon acoreensis was caught only twice bye me by direct hand sampling near the ground level.
At soil level in shady places you can also find the delicate sheet-webs of the linyphiine spider Leptyphantes acoreensis. All the mentioned spiders were supposed to be spread throughout the entire archipelago, and that sticks at the truth for all but one.
Other endemics are single-island endemics, and of these there aren’t much. Aditionally, I investigated some of them in collaboration with other specialists and at least one of them seems to be a synonymy with a species present in the Mediterranean. Other of these single-island endemics are subject to a somewhat suspicious view, being described in the basis of very small morphological differences by an author widely known for being a careless “splitter” and others remain unquestioned like Meioneta depigmentata (Linyphiidae) from Flores, Acorigone acoreensis (Linyphiidae) from São Jorge or Turinyphia cavernicola from Terceira (Linyphiidae).
Now, the new stuff:
Since these are all unpublished species, I will not write relevant information regarding their habitat and location. Please understand this.

A new species, sister of Savigniorrhipis acoreensis, was found present in one island only. Incorrectly identified material was present from previous works. This new species, more than morphologically, is ecologically separated from S. acoreensis, because it is present at ground level, while the latter is present at canopy level. This finding   provides a new look on the genus Savigniorrhipis, and hopefully it will either be validated or synonymised, but with a better analysis that that provided in its original description. Here it is the new species, it has a name, but I can’t reveal it by now as this would unmask the location of this tiny erigonine spider (on the bottom, the previously known endemic species S. acoreensis, both are females):

Also in the family Linyphiidae, one endemic species is now separated into 3 different species, one in each group of islands. The scientific work regarding these 3 species will take some time to be prepared and by now I can’t even confirm their genus with certainty.

These last fellas will be one of the major concerns regarding manuscripts in the next months for me. For these spiders I need the help on a more experienced arachnologist. When that publication sees the light of day, I will post here some further info on these little guys.

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