A new member of the genus Niphargus Schiödte , 1849 ( Amphioda Gammaridea , fam . Niphargidae ) from Crete Island , Greece ( Contribution to the knowledge of the Amphipoda 293 )

From the subterranean waters of Pyrgos, Crete island, Greece, is described and figured one new species of the family Niphargidae (Amphipoda Gammaridea), Niphargus lakusici, sp. nov., and its taxonomical position regarding other species of this genus known from Greece is discussed, and the list of known Niphargus species from Greece is given.


Introduction
Based on its specific geological history, geographical position, climate, scarcity of water and various ecological conditions, the fauna of the subterranean waters in Greece is very rich, but only partially known, despite numerous investigations provided by various scientists or scientific expeditions during last two century.Within these various investigations, numerous members of Crustacea Amphipoda have been discovered and described from the epigean and subterranean waters (caves, wells, springs, etc.)

by various
During our recent study of the subterranean amphipods from Greece, we described and figured here a new species of genus Niphargus from Crete Island, Niphargus lakusici, sp.nov.

Material and Methods
The collected material was preserved in the 70% ethanol.The specimens were dissected using a WILD M20 microscope and drawn using camera lucida attachment.All appendages were temporarily submersed in the mixture of glycerin and water for study and drawing.Later, all appendages have been transferred to Liquid of Faure on permanent slides.The body-length of examined specimens were measured by tracing individual's mid-trunk lengths (from tip of head to end of telson) using camera lucida.All illustrations were inked manually.
All studies in this work are based on the classic morphological, ecological and zoogeographical studies.
Mouthparts well developed.Labrum is broader than long, with nearly straight distal margin (fig.3A).
Labium is broader than long, with broad entire outer lobes and small but well developed inner lobes (fig.3B).
Maxilliped: inner plate short, not reaching distal outer tip of palpus article 1 and provided with 2-3 distal spines mixed with single setae longer than spines (fig.1G); outer plate reaching nearly half of palpus article 2 and provided with nearly 15 marginal spines and spine-like setae (fig.1G); palpus article 3 along outer margin with one distal bunch of setae; palpus article 4 at outer margin with one median plumose seta, at inner margin with 2 distal setae near basis of the nail (fig.1G).
Gnathopods 1 and 2 are nearly of the same size, much larger than corresponding coxa (fig.2A, C).Gnathopod 1: article 2 along anterior margin with 2 long proximal and 2-3 short distal setae, along posterior margin with several long setae (fig.2A); article 3 at posterior margin with one seta; article 5 much shorter that propodus (ratio: 35:75), along posterior margin with one distal bunch of setae.Propodus almost ovoid, much broader than long (ratio: 75:50), along posterior margin with 3 transverse rows of several setae only (fig.2C).Palm slightly convex, inclined nearly half of propodus-length, defined on outer face by one corner S-spine accompanied laterally by one strong L-spine, on inner face by one short subcorner R-spine (fig.2B), M-setae absent.Dactylus reaching posterior margin of propodus, along outer margin with one median seta, along inner margin with 4 short setae (fig.2A).
Gnathopod 2: article 2 along anterior margin with 3 short setae in distal part only, along posterior margin with a row of long setae (fig.2C).Article 3 at posterior margin with one seta; article 5 remarkably shorter than propodus (ratio: 45:67), along anterior margin with one distal seta only.Propodus nearly trapezoid, slightly longer than broad (ratio: 67:56), along posterior margin with 6 transverse rows of setae (fig.2C).Palm slightly convex, inclined slightly over half of propodus-length, defined on outer face by one corner S-spine accompanied laterally by one short L-spine, on inner face by one short R-spine, facial Msetae not observed (fig.2D).Dactylus reaching posterior margin of propodus, along outer margin with one median seta, along inner margin with 4 short setae (fig.2C).
Uropod 3 is not elongated: peduncle is longer than broad (ratio: 49:21), with single distal spines; inner ramus scale-like, much shorter than peduncle and provided with 2 distal spines (fig.3 I).Outer ramus 2-articulated: first article along outer margin provided with 4 groups of short spines, along inner (mesial) margin provided with 6 groups of spines (the longest spines almost reaching diameter of article itself), plumose setae are not observed; second article is much shorter than first article (ratio: 24:147), with 3 distal short setae only (fig. 3 I).
Telson longer than broad (ratio: 90:77), deeply incised; each lobe provided with 4 distal spines, one spine at inner (mesial) margin and with 0-1 spine along outer margin (fig.1H); a pair of unequal plumose setae appear near the middle of each lobe (on right lobe one plumose seta is missing).
Maxilla 1: inner plate with 2 setae, outer plate and palpus like these in holotype.Maxilliped: inner plate reaching mesial tip of palpus article 1 and provided with 2 spines and 3 setae; outer plate reaching half of palpus article 2 outer tip; and provided with 12 distomesial spines; palpus article 3 at outer margin with one distal bunch of setae; article 4 (dactylus) at inner margin with 2 setae near basis of the nail.
Coxa 1 with slightly concave ventral margin.Gnathopods 1-2 like these in holotype, propodus of gnathopod 1 along posterior margin with 3 transverse rows of small number of setae each; propodus of gnathopod 2 along posterior margin with 5 transverse rows of only several setae each; M-setae are not observed.
Article 2 of pereopods 5-7 with ventroposterior small lobe.Dactylus of pereopods 3-7 relatively slender, with one spine-like setae along inner margin near basis of the nail.
Uropods 1-3 like these in holotype, plumose setae along mesial margin of outer ramus are not observed.
Telson distinctly longer than broad, exceeding peduncle of uropod 3, deeply incised nearly 4/5 of telson-length; each lobe is provided with 4 distal spines, one distomesial spine; along outer margin of only left lobe appear one distomarginal spine; a pair of unequal plumose setae appears near the middle of each lobe.
The presence of subequal propodus of gnathopods 1 and 2 and short uropod 3 in males were observed in some taxa of Niphargus jovanovici-group, but telson of N. lakusici is without long plumose setae usually present in N. jovanovici-group.
Derivatio nominis: This species is dedicated to deceased botanist Prof. Dr. Radomir Lakušić from Sarajevo, Bosnia & Herzegovina, for his excellent studies of the flora and vegetation of Balkan peninsula.