NEW DATA OF THE SUBTERRANEAN SPECIES NIPHARGUS RHODI

The partially known species Niphargus rhodi S. Karaman, 1950b (Amphipoda, fam. Niphargidae) was described based on one female from the subterranean waters of Rhodos Island ["(spring on the Propheta Mt. (?Elias?)" (? = Profitis Ilias)], and later only mentioned by Pesce & Maggi (1983) for several localities of this island accompanied sometimes with amphipods Bogidiella longiflagellum S. Kar. 1959 or Medigidiella chappuisi (Ruffo, 1952). This species, discovered and collected in numerous localities on Rhodos Island by various scientists, is now redescribed and figured, and its variability and relation to other members of genus Niphargus of Greece and some adjacent regions is discussed.

Despite the fact that the subterranean fauna of the family Niphargidae in Greece was studied since 1934, when S. Karaman described some new taxa [Niphargus adei from Samothrake island and N. graecus from Akrokorinth in continental Greece], this fauna in Greece is still only partially known, and we can expect discovery of other new taxa from this region.
Regarding Rhodos Island (Aegean Sea), S. Karaman described (1950b) new species Niphargus rhodi based on one adult female from spring Nimpha on Mt.Propheta.Pesce & Maggi (1983) mentioned this species from several localities of Rhodos, but without any taxonomical data.
Thanks to the deceased Prof. Dr. Jan Stock from Holland, who sent us the samples of genus Niphargus collected from various subterranean waters of Rhodos Island, Greece, as well as by some samples sent me by Dr. Hans Malicky from Austria and Dr. Giuseppe Pesce from Italy, we have a possibility to redescribe taxonomically partially known species Niphargus rhodi S. Karaman, 1950b, despite the fact that within all numerous samples in hands.not final adult males were found.At the moment, N. rhodi is single Niphargus taxon known from this island.

MATERIAL AND METHODS
The studied 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 glycerine 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.Some morphological terminology and setae formulae follow G. Karaman's terminology (Karaman, G., 1969;2012c) regarding the last mandibular palpus article [A= setae on outer face; B= setae on inner face; D= lateral marginal setae; E= distal long setae] and propodus of gnathopods 1 and 2 [S= corner spine; L= lateral slender serrate L-spines; M= facial M-setae; R= subcorner R-spine on inner face].Terms "setae" and "spines" are used based on its shape, not origin.The study was provided using morphological, ecological and zoogeographical data.
Maxilla 1: inner plate with 2 unequal setae, outer plate with 7 spines [6 spines with one lateral tooth, one spine with 3 small lateral teeth] palpus 2articulated, not reaching distal tip of outer plate spines and provided with 6 distal setae (fig.3A).
Gnathopods 1 and 2 of moderate size.Gnathopod 1: article 2 along both margins with long setae; article 3 at posterior margin with one bunch of setae (fig.2A).Article 5 is shorter than propodus (ratio: 36:47), along anterior margin with one distal bunch of setae (fig.2A).Propodus trapezoid, nearly as large as corresponding coxa, slightly longer than broad (ratio: 87:80), along posterior margin with 7 transverse rows of setae (fig.2B); palm inclined slightly less than half of propodus-length, convex, defined on outer face by one corner S-spine accompanied laterally by 2 L-spines and 4 long facial M-setae (fig.2C), on inner face by one subcorner R-spine.Dactylus reaching posterior margin of propodus, along outer margin with 5 median setae, along inner margin with 5 short setae (fig.2B).Gnathopod 2 remarkably larger than gnathopod 1 and corresponding coxa 2 (fig.2D); article 2 along anterior margin with row of shorter setae, along posterior margin with row of long proximal setae and short distal setae; article 3 at posterior margin with one bunch of setae; article 5 shorter than propodus (ratio: 48:60), along anterior margin with distal bunch of setae.Propodus trapezoid, remarkably larger than that of gnathopod 1, poorly longer than broad (ratio: 112:106), along posterior margin with 11 transverse rows of setae (fig.2E); palm slightly convex, inclined nearly half of propodus-length, defined on outer face by one corner S-spine accompanied laterally by 2 L-spines (close to Sspine) and 3 long facial M-setae, on inner face by one subcorner R-spine (fig.2F).Dactylus reaching posterior margin of propodus, along outer margin with 5 median setae, along inner margin with 5 short setae (fig.2E).
Pereopod 4: article 2 pilosity is similar to that of pereopod 3; articles 4-6 of unequal length (ratio: 55:34:43); article 4 at anterior margin with 3 single slender spines, along posterior margin with 5 single or paired setae (the longest setae reaching diameter of article itself); article 5 at posterior margin with single spines and setae; article 6 along posterior margin with 4 groups of short spines (fig.3D).Dactylus short and strong, at inner margin with one spine near basis of the nail, along outer margin with one median plumose seta; nail slightly shorter than pedestal (ratio: 25:35) (fig.3E).
Pereopods 5-7 are moderately slender.Pereopod 5 is remarkably shorter than pereopods 6 and 7, with article 2 longer than broad (ratio: 72:46), along anterior margin with 9 groups of setae, along posterior convex margin with nearly 10 seta of unequal length (fig.4A), ventroposterior lobe not fully developed, distoanterior corner is not produced.Articles 4-6 of unequal length (ratio: 45:51:57); article 4 at anterior margin with row of short setae, along posterior margin with one median and one distal spine; articles 5 and 6 along both margins with groups of spines and single short setae.Article 2 is longer than article 6 (ratio:72:57).Dactylus is short and strong, much shorter than article 6 (ratio: 18:57), at inner margin with one strong spine, along outer margin with one median plumose seta; nail is shorter than pedestal (ratio: 22:40) (fig.4B).
Uropod 1: peduncle with dorsoexternal row of strong spines and dorsointernal row of spine-like setae (except distal spine) (fig.5E).Outer ramus as long as inner ramus but shorter than peduncle (fig.5E), along lateral margins appear 3 pairs of spines accompanied by 2 bunches of simple setae, at the tip are attached 4-5 unequal distal spines.Inner ramus along margins with 3 spines and one bunch of simple setae, at tip appear 4-5 short spines.
Uropod 2: both rami of the same length, bearing several lateral and distal spines, setae are absent (fig.5D).
Telson slightly longer than broad (ratio: 75:66), rather gaping, incised nearly ¾ of telson-length; each lobe with 3-4 distal and one outer marginal spine (fig. 1 I); a pair of short plumose setae appear at outer margin near the middle of each lobe.
Head and antennae 1-2 like these in female.Antenna 1 hardly exceeding half of the body, consisting of 21 articles (most of them with one aesthetasc); accessory flagellum short, 2-articulated.Flagellum of antenna 2 longer than last peduncular article and consisting of 7 articles.
Maxilla 1 inner plate with 2 setae, outer plate with 7 spines (6 with one lateral tooth, one spine with 3-4 lateral teeth); palpus not reaching distal tip of outer plate spines and bearing 5-6 setae.Maxilla 2 with subequal both lobes bearing marginal setae only.Maxilliped inner plate reaching outer tip of palpus article 1, bearing 5 pointed teeth, outer plate with 9-10 spines; palpus article 3 along outer margin with 1-2 median and one distal group of setae, article 4 at inner margin with 2 setae near basis of the nail.
Uropod 1: peduncle longer than rami, with dorsoexternal row of spines and dorsointernal row of spine-like setae (except distal spine), distal tubercle absent (fig.5 I); rami of equal length, bearing several lateral and 5 distal spines; outer ramus with one median group of simple setae only (fig. 5 I).
Uropod 3 like that in female: peduncle short, with several distal spines; inner ramus short, scale-like, with one distal spine and seta (fig.7C); outer ramus 2-articulated: first article long, along outer margin with 5 bunches of short spines, along inner (=mesial) margin with 6 bunches of short spines mixed often with one longer plumose seta (fig.7C); distal article much shorter than first one (ratio: 34:142), provided with several short simple setae along both margins.
Telson slightly longer than broad (ratio: 88:78), incised slightly over 2/3 of telson-length; each lobe is provided with 3 distal spines and 0-1 spine at mesial margin (fig.7D); a pair of unequal plumose setae is attached near the external side of each lobe.
probably with the similar shortened second article of uropod 3 outer ramus and equal rami of uropod 1.Among known Niphargus species from Greece, provided with a row of setae along outer margin of gnathopods 1-2 dactylus, there are several taxa with uropod 1 rami of equal length (N.rhodi, N. lindbergi, N. lourensis, N. impexus, N. koukourasi).
N. impexus G. Karaman 2016a, described from Creta Island is rather similar to N. rhodi, but females of N. impexus differ from these of N. rhodi by higher number of setae on maxilla 1 inner plate, by low number of spines on maxilliped inner plate as well as by long uropod 3 outer ramus article 2 in all males, etc.
N. koukourasi, Ntakis et al. 1915, described from Springs of Louros River, Vouliasta, Ioannina (continental Greece) differs from N. rhodi by highly spiniferous telson provided with facial spines, by higher number of setae on maxilla 1 inner plate, etc.
Niphargus lourensis Fiser et al. 2006, described from Spring of Louros River, Vouliasta, Ionannina, continental Greece, differs by shorter and more spiniferous outer ramus of uropod 3 having very short distal article, by telson with long distal spines only, etc.
The recently discovery of numerous Niphargus taxa by various scientists in Turkey [Niphargus anatolicus S. Karaman, 1950a from Emirgan, N of Istanbul; N. religious G. Karaman 2012a from Uragavaz Gecidi, Ballidag (Kastamonu), 1350 m. a.s.l., etc.], from Iran [Niphargus hakani Esmaeili-Rineh et al. 2017 from Kheder-Goli spring, Razan city, Hamedan Province, etc.], and Iraq [Niphargus nadarini iraquensis G. Karaman, 2012b from Haditha (El Hadithah), etc.] show the large distribution of genus Niphargus in entire SE Europe, Asia Minor and Near East, and the further investigations of this genus in these regions will help to understand the real taxonomical position of taxa from Greece and adjacent regions.

CONCLUSIONS
Niphargus rhodi S. Karaman, 1950, known from Rhodos island (Greece) only, is redescribed and figured based on numerous localities from Rhodos island (adult females up to 7.5 mm and non quite adult males of up to 5.8 mm.).The males in hands are similar to females, including uropods and gnathopods.Within nearly 15 known Niphargus taxa from Greece, N. rhodi is well distinguished by various taxonomical characters (uropods 1-3, telson, gnathopods, mouthparts, etc).The exact position of N. rhodi within genus Niphargus is not possible to determine without knowledge of final adult males.