Hadzinia ferrani, sp. n. (Opiliones: Nemastomatidae), a highly specialized troglobiotic harvestman from Slovenia
Author
Novak, Tone
Department of Biology, Faculty of Natural Sciences and Mathematics, University of Maribor, Koroška 160, SI- 2000 Maribor, Slovenia. E-mail: tone. novak @ uni-mb. si
Author
Kozel, Peter
Karst Research Institute IZRK ZRC SAZU, Titov trg 2, SI- 6230 Postojna, Slovenia. E-mail: peter. kozel @ zrc-sazu. si
text
Zootaxa
2014
2014-07-24
3841
1
135
145
journal article
5417
10.11646/zootaxa.3841.1.8
8679cc28-c25c-442f-a18c-76dc15c78b0f
1175-5326
4928308
4323F034-7650-480C-8744-6ADF5CA24437
Hadzinia
Šilhavý, 1966
Diagnosis
. Genus of very small (below
1.5 mm
), long-legged (leg II up to 23-times the length of body) troglobiotic
Nemastomatidae
, characterized by distinctive male genital morphology. Ocular tubercle low or absent, eyes reduced. Male cheliceral apophysis and cheliceral gland openings absent. Pedipalps very long, 5.2−5.7-times as long as body, tarsus proximally conspicuously bent to ventral side. Truncus thin, base bifurcated. Glans truncated cone-like to elongate barrel-like shaped, slightly wider than truncus. Glans terminally truncated, with two lateral humps encompassing furrow and subapically emerged stylus on the ventral side in the middle of furrow, pointed in dorsal and ventral view. According to present knowledge, of scattered distribution in the central and western Dinaric region. Currently two described species (but compare
Karaman 2013
).
Karaman (2013)
suggests that the unusual distribution of
Hadzinia
and
Nemaspela
could indicate their relict status as elements of the paleo-European mainland fauna. This is justified, but the distinctive genital morphologies indicate that these two lineages most probably evolved from various ancestors which independently colonized the subterranean environment. While
Nemaspela
seems to be a subterranean offshoot of the
Giljarovia
ancestor (
Martens 2006
),
Hadzinia
may have originated from the same ancestor as
Pyza
or
Vestiferum
.
It should be noted that
Nemaspela femorecurvata
Martens, 2006
and
N. ladae
Karaman, 2013
have been the only species in the genus missing the male cheliceral apophysis, which is also missing in
Hadzinia
.
Dunlop & Mitov (2009)
argue that the shape of the male cheliceral apophysis, viewed in isolation, is insufficient to identify the genus, since a few nemastomatid genera may evince a similar shape. Furthermore, its absence in highly adapted troglobionts is
per se
not a useful characteristic for identification, since it may be just one convergence in a series of several adaptations to subterranean habitats. Therefore, genital morphology is of greatest importance in considering relationships between the studied taxa, as has been established for other opilionid groups (
Derkarabetian
et al.
2010
). In this way, the external similarities between particular
Hadzinia
and
Nemaspela
species
imply either general adaptive convergence to the hypogean habitat, or convergence triggered either by living in similar habitats or by preying on comparable prey. All this additionally supports Karaman’s opinion that in these genera we are investigating a special case of evolution within paleo-European mainland fauna with respect to Balkans-Caucasus opilionid congeners. Phylogenetic investigation could contribute much to clarifying the relationships among the alleged taxa.