Studies of the genus Enchodelus Thorne, 1939 (Nematoda, Nordiidae) from Arctic polar deserts. 1. Species with long odontostyle: E. makarovae sp. n. and E. groenlandicus (Ditlevsen, 1927) Thorne, 1939, with an identification key to the species of the E. macrodorus group Author Elshishka, Milka Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences Author Lazarova, Stela Author Peneva, Vlada K. text ZooKeys 2012 2012-07-30 212 1 23 http://dx.doi.org/10.3897/zookeys.212.3464 journal article http://dx.doi.org/10.3897/zookeys.212.3464 1313-2970-212-1 660A11441BCA4D4B9589189B73CA77D7 FFA71C24FFF6FF9E373D9919FFC7FFFA 577419 Enchodelus groenlandicus (Ditlevsen, 1927) Thorne, 1939 Figs 7 11 Material examined. Ten females collected from Putorana Plateau, Russian Arctic ( Table 1 ). Measurements. See Table 4 . Description. Female . Nematodes of medium to large size, habitus from slightly curved ventrad to open C- shape after fixation. Cuticle with fine, but distinct transverse striations, especially visible at neck and on tail regions; 4-6 µm thick at postlabial region, 3-4 µm at mid-body and 7-8 µm on tail. Lateral chord narrow, 6-9 µm wide or occupying ca 9-13 % of mid body diam. Lip region rounded, offset by a depression, 2.3-3.1 times as wide as high. Amphidial fovea cup-shaped, located at level of labial depression, occupying 65% of lip diam. Cheilostom cylindrical. Odontostyle long, 2-2.5 times longer than lip region diam. or 2.2-2.7% of total body length. Odontophore distinctly flanged, 1.1-1.3 times as long as odontostyle. Guiding ring double, located 1.4-1.6 lip region diam. from anterior end. Pharynx attains full width at 56-64% of its length from anterior end. Pharyngeal characters are presented at Table 3 . Cardia rounded measuring 6-10 x 15-17 µm . Genital system amphidelphic, both branches equally and well developed, anterior 277-370 µm , posterior 287-375 µm long. Ovaries relatively large, 142-303 µm long; oocytes firstly in two or more rows, then in a single row. Anterior and posterior oviduct 119-143 µm (n=9) and 119-153 µm (n=8) long, 1.6-1.9 and 1.6-2.0 times body diam. respectively, consisting of slender part and well developed pars dilatata oviductus . Sphincter distinct. Uterus thick walled, tripartite, consisting of a wider proximal portion with distinct lumen, followed by a narrower median portion (43-115 µm (n=4)) and ending with a well developed spheroid pars dilatata distalis . Vagina extending inwards 42-53 μ m or 53-68 % of body diam., pars proximalis 25-30 µm x 21-22 µm , pars refringens with two trapezoid sclerotisations, with a combined width of 18-18.5μm and length 6-8 μm (n=2) pars distalis 6 µm long (n=2). Vulva a transverse slit, pre-equatorial (40-47%). Eggs observed in eight females, measuring 96 -109 x 43-64 µm , most frequently located in pars dilatata oviductus (n=6), rarely in uterus (n=2). Prerectum 3-4.5 anal diam. long, rectum 0.8-1.0 times anal body width. Tail hemispheroid. Numerous small elongated saccate bodies observed on tail, mostly on ventral side. Hyaline part of tail 8.0-10 µm thick or 25-33 % of total tail length. Male . Unknown Locality and plant associations. Different types of vegetation from a polygonal polar desert on Plateau Putorana, Russian Arctic ( Table 1 ). Remarks. The data on Enchodelus groenlandicus geographical distribution, i.e . the original description from Disko Island, Greenland ( Ditlevsen 1927 ) and recent reports from Spain, Albania and Iran ( Guerrero et al. 2008 , Andrassy 2009b , Pedram et al. 2011 ) indicate a disjunctive type of range. It occurs at high altitudes 950 m to 2450 m a.s.l in Southern Europe and Iran, and at high latitudes in the polar region (Putorana Plateau and Greenland), Guerrero et al. (2008) hypothesize that such a distribution pattern might stem from quaternary glacial events. The specimens examined generally agree well with data reported for this species, although some differences occurred: the Arctic population has somewhat shorter odontostyles (43-47 vs 44-53 µm ) and a more anterior position of the vulva (40-46 vs 41.5-49.4%, see Table. 4 for details); Iranian specimens had shorter female tails (19-24 vs 28-33 μ m and c' = 0.4-0.6 vs 0.5-0.7). We consider the morphometric differences as representing intraspecific variation . Figure 7. Enchodelus groenlandicus . A-D Female A Neck region B Anterior genital branch C, D Entire body. Scale bars: A, B 50 µm ; C, D 500 µm . Figure 8. Enchodelus groenlandicus . A-F Female A, C Vulval region and uterus B Vulval region D Anterior region, lateral view E Amphidial fovea F Anterior region, ventral view. Scale bars: A-F 50 µm . Figure 9. Enchodelus groenlandicus . A-E Female A-E Tail ends. Scale bars: A-E 50 µm . Figure 10. Enchodelus groenlandicus . A-K Female : A, B Anterior region C, D Amphideal fovea E Entire body F-H Tail ends I Subterminal caudal pores indicated by arrows J Tail with saccate bodies K Tail in ventral view, anus marked by an arrow. Scale bars: A-D, F-K 50 µm ; E 1 mm. Figure 11. Enchodelus groenlandicus . A-E Female : A Pharyngeal bulb B Pars dilatata distalis uteri (arrows) C Vulval region in subventral view D, E Vulval region in lateral view. Scale bars: A-E 50 µm . Table 4. Morphometrics for females of Enchodelus groenlandicus (Ditlevsen, 1927) Thorne, 1939. All measurements, unless indicated otherwise, are in µm (and in the form: mean +/- SD (range).

Characters	Russia - Putorana Plateau		Greenland	Spain	Albania	Iran
-	Present study		Ditlevsen 1927	Guerrero et al. 2008	Andrassy 2009	Pedram et al. 2011
-	DB1	DB, GC, C	-	-	-	-
n	7	3	1*	14	2	4
L (mm)	1.94 +/- 0.16(1.8-2.16)	1.77, 1.70, 1.92	2.5	1.78 +/- 0.15(1.57-2.07)	1.54-1.68	1.86 +/- 0.09(1.76-1.97)
a	24.4 +/- 1.8(21.7-25.9)	24.3, 25.9,	25	23.4 +/- 1.6(21.3-25.3)	22-23	23.0 +/- 2.5(20.3-26.0)
b	5.3 +/- 0.3(5-5.6)	4.6, 4.7, 4.8	6	5.1 +/- 0.3(4.5-5.5)	4.0-4.6	5.0 +/- 0.2(4.6-5.1)
c	64.9 +/- 4.9(59.9-70.8)	61.5, 52.4, 62.1	50	67.5 +/- 9.2(53-83)	40-46	85.5 +/- 14.0(73-104)
c'	0.6 +/- 0.1(0.5-0.7)	0.6, 0.7, 0.7	0.7	0.7 +/- 0.1(0.6-0.8)	0.7-0.8	0.5 +/- 0.1(0.4-0.6)
V %	42.4 +/- 1.8(40-44)	46, 43, 42	43	44.2 +/- 1.9(41.6-49.4)	44-45	42.5 +/- 1.0(41.5-44.0)
Lip region width	19.8 +/- 0.8(19-20.5)	21, 21, 19	20	20.5 +/- 0.9(19-22)	19-20	22.5 +/- 0.5(21-23)
Odontostyle	46.7 +/- 0.4(46-47)	47, 44, 43	48-49	49.3 +/- 2.3(44-53)	50-51	48.5 +/- 0.5(48-49)
Odontophore	49 +/- 0.2(48.7-49)	50, 48, 55	49	50.4 +/- 2.9(45-55)	52-54	52 +/- 1(51-53)
Spear	95.6 +/- 0.3(95-96)	97.5, 93, 98	98	100 +/- 4.1(94-108)	102-106	102.5 +/- 1.0(101-103)
Anterior end to guiding ring	30.4 +/- 1.9(29-33)	30, 28, 30	29	32.8 +/- 2.4(27-37)	-	-
Neck length	376.6 +/- 12.4(361-398)	389, 361, 398	417	354 +/- 24.0(322-401)	-	377.5 +/- 19.0(350-392)
Width at pharynx base	68.5 +/- 3.9(65-75)	69, 60, 62	-	66.0 +/- 9.0(49-75)	-	78.5 +/- 5.0(75-82)
Width at mid body	79.5 +/- 4.1(75.5-83)	73, 66, 68	100	76.1 +/- 5.5(67-87)	77-80	82.0 +/- 9.5(68-89)
Prerectum length	185.6 +/- 10.6(178-193)	187,-, 213	50	186 +/- 36(116-252)	-	203.0 +/- 19.5(176-223)
Rectum length	42.1 +/- 2.5(39-44.5)	38, 46, 42	-	42.1 +/- 7.3(27-52)	-	-
Tail	29.9 +/- 1.7(28-32)	29, 33, 31	31	26.8 +/- 4.2(22-37)	28-30	22.0 +/- 2.5(19-24)

*followed by Guerrero et al. 2008 Identification key to species belonging to Enchodelus macrodorus group

1	Odontostyle ≤ 36 µm ; uterus bipartite (♀ L=1.85 mm, a=20, b=5.1, c=58, c' =0.76, V=53%, Odontostyle=36 μm ; ♂ unknown) (India)	Enchodelus distinctus (Ahmad & Jairajpuri, 1980)
-	Odontostyle ≥37 µm ; uterus tripartite	2
2	Lip region separated by constriction	3
-	Lip region separated by depression	4
3	Body long (>1.6 mm) (♀ L=1.8-2.38 mm, a=21-34, b=4.8-6.1, c=54-92, c' =0.6-0.9, V=44-50%, Odontostyle=38-45 µm ; ♂ L=1.66-2.21mm a=24.4-32.7, b=5.1-5.9, c=53.2-68, c' =0.7-0.8, Odontostyle=27.5-40 µm , Spicules= 56-70 µm ) (Romania, Spain)	Enchodelus saxifragae (Popovici, 1995)
-	Body short (<1.6 mm) (♀ L=1.21-1.56 mm, a=20-25.5, b=3.0-5.0, c=60.5-92.5, c' =0.5-0.7, V=44-49%, Odontostyle=40-45 μm ; ♂ L=1.31-1.53 mm, a=22.5-28, b=4.3-5.1, c=49-71.5, c' =0.5-0.9, Odontostyle=39-44 μm , Spicules=49-61 μm ) (Iran)	Enchodelus babakicus (Pedram et al., 2009)
4	Uterus short (1-2 times corresponding body diam.) (♀ L=1.38-1.92 mm, a=19-32, b=4.0-6.2, c=55-91, c' =0.5-0.7, V=37-47%, Odontostyle=37-44 μm ; ♂L=0.94-2.16 mm, a=19-39, b=3.6-6.0, c=41-100, c' =0.6-0.9, Odontostyle=24-33 µm , Spicules=46-70 µm ) (Holarctic region)	Enchodelus macrodorus (de Man, 1880) Thorne, 1939)
-	Uterus long(> 2 times corresponding body diam.)	5
5	Body length <1.3 mm; (♀ L=0.94-1.29 mm, a=19-28, b=3.5-5.6, c=47-73, c' =0.5-1.0, V=43-55%, Odontostyle=37-45 μm ; ♂ L=1.24-1.28 mm, a=26-37, b=4.6-4.8, c=52-54, c' =0.7-0.8, Odontostyle=38-40 μm , Spicules = 45-50 μm ) (India, Korea)	Enchodelus microdoroides (Baqri & Jairajpuri, 1974)
-	Body length>1.5 mm	6
6	Dorsal cell mass near cardia present. (♀ L=1.59-1.87 mm, a=21.1-28.6, b=4.3-5.3, c=55.3-87.5, c' =0.5-0.7, V=41.7-49.7%, Odontostyle=39.5-47 μm ) (Romania)	Enchodelus carpaticus (Ciobanu et al., 2010)
-	Dorsal cell mass near cardia absent	7
7	Lip region narrow <18 µm , males present (♀ L=1.57-2 mm, a=21.6-33.1, b=4.4-5.7, c=45.8-70.3, c' =0.6-0.9, V=45-51%, Odontostyle=38-43 µm ; ♂ L=1.49-1.79 mm, a=19.6-29.8, b=4.4-5.4, c=46.4-58.9, c' =0.7-0.8, Odontostyle=39-44.5 µm , Spicules=65-74 μm ) (Russia - Severnaya Zemlya Archipelago)	Enchodelus makarovae sp. n.
-	Lip region wide,> 19 μm , males absent (♀ L=1.54-2.5 mm, a=20.3-25.9, b=4.0-6.0, c=40-104, c' =0.4-0.8, V=40-49%, Odontostyle=43-51 μm ) (Greenland, Spain, Albania, Iran, Russia - Putorana Plateau)	Enchodelus groenlandicus (Ditlevsen, 1927)
-