Advances in the systematics of the spider genus <i>Troglohyphantes</i> (Araneae, Linyphiidae)

<p>With 128 described species and five subspecies, the spider genus <i>Troglohyphantes</i> (Araneae, Linyphiidae) is a remarkable example of species diversification in the subterranean environment. In this paper, we conducted a systematic revision of the <i>Troglohyphantes</i> species of the Italian Alps, with a special focus on the <i>Lucifuga</i> complex, including the description of two new species (<i>T. lucifer</i> sp. nov. and <i>T. apenninicus</i> n. sp.). In addition, we provided new diagnostic drawings of the holotype of <i>T. henroti</i> (<i>Henroti</i> complex) and established three new synonymies within the genus. The molecular analysis of the animal DNA barcode confirms the validity of this method of identification of the Alpine <i>Troglohyphantes</i> and provides additional support for the morphology based species complexes. Finally, we revised the known distribution range of additional <i>Troglohyphantes</i> species, as well as other poorly known alpine cave-dwelling spiders.</p> <p><i>Troglohyphantes lucifer</i><a href="http://www.zoobank.org/urn:lsid:zoobank.org:act:AB4B644A-D18A-4EB7-99E7-B5117AED5389" target="_blank">http://www.zoobank.org/urn:lsid:zoobank.org:act:AB4B644A-D18A-4EB7-99E7-B5117AED5389</a></p> <p><i>Troglohyphantes apenninicus</i><a href="http://www.zoobank.org/urn:lsid:zoobank.org:act:3C86E78E-7145-4F0C-803E-2A909201579C" target="_blank">http://www.zoobank.org/urn:lsid:zoobank.org:act:3C86E78E-7145-4F0C-803E-2A909201579C</a></p

The maximum strength of different types of (mainly spider) silks.

<p>The maximum strength of different types of (mainly spider) silks.</p

FESEM characterization of the silk stalk at different magnifications.

<p>FESEM characterization of the silk stalk at different magnifications.</p

FESEM characterization of the stalk cut with FIB: (a, b, c) at an eye angle of 52°, (d) from the top.

<p>FESEM characterization of the stalk cut with FIB: (a, b, c) at an eye angle of 52°, (d) from the top.</p

Egg sac of the spider <i>Meta menardi.</i>

<p>Photo by Francesco Tomasinelli (2009).</p

Distinction of the stalk types: cable-like (Group A) (a) and ropey-like (Group B) (b).

<p>Distinction of the stalk types: cable-like (Group A) (a) and ropey-like (Group B) (b).</p

The maximum toughness of different types of (mainly spider) silks.

<p>The maximum toughness of different types of (mainly spider) silks.</p

FESEM image of the spinnerets of <i>Meta menardi</i> (1. Anterior lateral; 2. Posterior median; 3. Posterior lateral).

<p>FESEM image of the spinnerets of <i>Meta menardi</i> (1. Anterior lateral; 2. Posterior median; 3. Posterior lateral).</p

The measured stress of each stalk, in ascending order.

<p>The measured stress of each stalk, in ascending order.</p

The maximum strain of different types of (mainly spider) silks, showing the record for egg sac silk stalks observed in our experiments.

<p>The maximum strain of different types of (mainly spider) silks, showing the record for egg sac silk stalks observed in our experiments.</p