Eurycercus longirostris Hann, 1982 , p. 587 Elías-Gutiérrez et al. 1997 , p. 65 Bekker et al. 2010 , p. 2501 Eurycercus vernalis Hann, 1982 , p. 595 A revision of the subgenus Eurycercus (Eurycercus) Baird, 1843 emend. nov. (Cladocera: Eurycercidae) in the Holarctic with the description of a new species from Alaska Bekker, Eugeniya I. Kotov, Alexey A. Taylor, Derek J. Zootaxa 2012 2012-02-24 3206 1 1 40 3D3K6 Hann, 1982 Hann 1982 [151,586,1837,1863] Branchiopoda Eurycercidae Eurycercus Animalia Diplostraca 18 19 Arthropoda species longirostris   Figs 6–7      Eurycercus longirostris Hann, 1982, p. 587–595, Figs 1–25;  Elías-Gutiérrez et al.1997, p. 65, 67–68, Figs. 9–13;  Bekker et al.2010, p. 2501, Fig. 12.     Eurycercus vernalis Hann, 1982, p. 595–596.   Type locality."Big TurkeyLake, Lagrange Co" ( Hann 1982), Indiana, U.S.A.Approximate geographic coordinates: 41.59, -85.19.   Holotype.A parthenogenetic female, 1.44 mm, in alcohol, USNM 181893.    Paratypes.A parthenogenetic female on a slide in glycerine jelly, USNM 181895. Two parthenogenetic females in alcohol, and one parthenogenetic female in glycerine jelly on a slide, NHM 1980.371, 1980.372. A parthenogenetic female in alcohol, and one parthenogenetic female in glycerine jelly on a slide, CMNC-1981-217. An ephippial female in glycerine jelly, USNM 181896. “In addition, one exuviamounted in polyvinyl lactophenol on a slide has been deposited in each of the three museums listed above. All other specimens are in the author's collection” ( Hann 1982).    Allotype.A mature male in glycerine jelly, USNM 181894.  Material examined here:   Canada. British Columbia. MoreiLake, coll. in  02.07.2005by M. Belyaeva& S. Ishida, DJT 3-618( 59.955, -132.024).   Manitoba. Fish House Pond, Boatdoek at Delta Marsh Field Station, coll. in  19.09.1982by M. M. Boucherle, DGF 6770(49.97, -98.29); Weir Channel, Churchill, coll. in  16.08.2006by M. Eíias-Gutiérrez, AAK M-0898 and AAK M-0891 ( 58.672, -94.161).   Newfoundland and Labrador. Ocean Pond, coll. in  03.07.2005by L.J. Hovind& M. Faustova, AAK M-0487 ( 47.4442, -53.4118).   Nova Scotia.A lake, west side of Hgy.349,  0.5 milesN of Williamswood/ Harrietsfieldboundary, coll. in  31.10.1984by D. G. Frey, DGF 7328(44.55, -63.64).   Ontario.Pond  3 milesE Manitoba/  Ontarioborder, on Trans-Canada Hwy, coll. in  29.08.1974by D. G. Frey, DGF 3660(49.73, -95.11); Pond on Opeongo Road, Algonquin Park, coll. in  08.10.1982by S & F, DGF 6446(45.56, -78.6); Sydenham Lake, Sydenham, coll. in  11.10.1982by S & F, DGF 6490( 44.4226, - 76.5559).   Yukon. SquangaLake, coll in  02.07.2005by M. Belyaeva& S. Ishida, DJT 3-624, DJT 3-625and AAK M-0477 ( 60.4478, -133.603).    U.S.A. Alaska. Birch Lale, Anchorage, coll.  8.08.2011by D. J. Taylor, A. A. Kotov, M. Ballinger& A. Medeiros, DJT20_2011_ Ancourage_04 ( 61,14558, -149,9384).   California.CPR Pond2, coll. in  01.05.2001by E. Gallo, AAK 2007-319; Lower Twin Lakein Robinson, Creek Valley, coll. in  12.09.1965by D. G. Frey, DGF 1726( 40.5066, -121.3639).   Colorado. Ponded Brookletnear Upper Red Rock Lake, coll. in  02.09.1975by D. G. Frey, DGF 1704( 40.0816, -105.5412).   Connecticut. BeachPond, coll. in  14.06.2004by D. J. Taylor& A. A. Kotov, AAK 2005-234( 41.5837, -71.7222).   Indiana. HammondLake, coll. in  29.10.2006by S. Ishida& K. Kim, AAK M-1124 ( 41.3647, -85.6775);  OliverLake, coll. in  25.11.1966by D. G. Frey, DGF 2342( 41.5724, -85.4051); Silver Lake, coll. in 29.10.2006by S. Ishida & K. Kim, AAK M-1128 (41.08, -85.9).   Maine. Meddybemps Lake, Hgy.119,  Moosehorn Wildlife Refuge, coll. in  09.11.1984by G. Frey, DGF 7346(45.07, -67.37);  SebagoLake, coll. in  11.08.1966by D. G. Freyand 09.1981 by D. B. Berner, DGF 1911, DGF 1874and AAK 1999-103 ( 43.778, - 70.518).   Massachusetts. Pequot Pond, coll. in  26.06.2004by A. A. Kotov& W. Piel, AAK M-0076 (42.18, - 72.692).   Michigan. Douglas Lake, MarlBay, coll. in  29.07.1961by D. G. Frey, DGF 0295(45.58, -84.69);  HamiltonLake, coll. in  07.07.1966by D. G. Frey, DGF 1857( 45.7551, -87.7854);  TwinLake, coll. in  31.01.1975by D. G. Frey, DGF 0303( 43.3676, -86.1716).   Minnesota. Newton Lakein BWCA near  Ely, coll. in  08.08.1979by D. G. Frey, DGF 5250( 47.9768, -91.7273).   Mississippi. Pearl RiverSystem, Chien's Sta. 3, 1.2 milesSW of jct. 411 on State Road12 near  McCool, coll. in  09.05.1974by D. G. Frey, DGF 3413(33.21; -89.36); Roadsideditch, Hwy39W, ca.  4 milesS of Indianola , coll. in  13.03.1978by D. G. Frey, DGF 4583(33.5, -90.6).   New Hampshire. Otter Pondnear  SunapeeLake, coll. in  24.06.2004by W. Pill& A. A. Kotov, AAK 2005-255( 43.4303, -72.0587);  Sunapee Lakeat  Brich Point, coll. in  24.06.2004by W. Piel& A. A. Kotov, AAK 2005-264- 265(43.3756, -72.07).   New York. Fishpondnear Atlanticcity  Reservoir, coll. in  01.05.1995by H. Segers, AAK 1998-014(39.44, -74.55); Lake Erie, coll. in 25.06.2006by L. Hovind, AAK M-0272 ( 42.8503, -78.8742);  Pond3,  Brigantine National Wildlife Refuge, coll. in  08.05.1995by H. Segers, AAK 1998-016(39.4, -74.4); Round Pond,  Long Island, coll. in  12.06.2004by D. J. Taylor& A. A. Kotov, AAK 2005-223( 40.9857, -72.2914).   North Carolina. Lake Carolina, coll. in  07.06.2005by L.J. Hovind, DJT 20-129( 35.475, -79.075);  PagesLake, coll. in  18.08.1958by P. Patterson, DGF 0050( 35.1379, -79.4304);  Panther Lake,  02.03.1979by D. G. Frey, DGF 3759( 35.5678, -78.6955).   Pennsylvania. Swingle Road Pond, coll. in  11.06.2004by D. J. Taylor& A. A. Kotov, DJT 20-004( 41.4154, -75.3162);  Swingle Road Pond, coll. in 06.2004 by D. J. Taylor& A. A. Kotov, AAK 2005-219( 41.4154, -75.3162).   Rhode Island. Bowdish Reservoir, coll. in  14.06.2004by D. J. Taylor& A. A. Kotov, AAK 2005-236and DJT 20-037 ( 41.9242, -71.7826).   Tennessee. Poolbetween road and Reelfoot Lake,  1 mileN of Dods, Tennessie Nat. Wildlife Ref. , coll. in  11.10.1974by D. G. Frey, DGF 3427(36.4, -89.4).   Vermont. CrystalLake, coll. in  26.03.1975by D. G. Frey, DGF 2600( 44.7338, -72.1539).   Washington. Green Lake, Seattle, coll. in  22.10.1983by D. G. Frey, DGF 6695( 47.6784, -122.3381);  Slough, upper end of  Lake Quinault, Rain Forest Camp, Olympic Peninsula, coll. in  27.06.1978by D. G. Frey, DGF 4895(47.49, -123.85).   Wisconsin. FoxLake, coll. in  23.06.1956by D. G. Frey, DGF 0248( 43.5822, -88.919).   Mexico. State of   Mexico. Lake La Luna, in the crater of the volcano  Nevadode Toluca, coll. in  04.06.1994by M. Elías-Gutiérrez, AAK 2002-106 ( 19.1036, -99.7556).    Diagnosis.Parthenogenetic female.Dorsal head pores on a bubble-like projection located immediately on head shield. In anterior view, body wide, not compressed laterally, median dorsal keel absent. Rostrum relatively long. Ocellus of moderate size. Lateral head pore circular. Labrum with a moderate median keel, with broadly rounded apex, reaching distal end of antenna I length. Postabdomen with sub-parallel dorsal and ventral margins, preanal teeth pointed. Spines at base of pre-claw portion predominantly single. Antenna I with antennular sensory seta arising somewhat basally to middle. Denticles in rows encircling antennular surface relatively large. On antenna II, spine situated on proximal segment of exopod equal to or somewhat shorter than second segment. Limb I IDL with a strong hook-like seta, the smallest IDL seta especially fine and short. IDL with about 4–11 distal spinules, 3–15 proximal spinules, 1–11 marginal spinules and 0–12 basal spinules. Eight setae in filter plate II, 9 setae in filter plate III; 9 setae in filter plate IV, 8 setae in filter plate V.   Short redescription.Parthenogenetic female.In lateral view body sub-ovoid in larger females ( Fig. 6A), maximum height of the body in its middle portion (BH/BL= 0.57–0.59). Dorsal margin interrupted only by a bubble-like head pore. In anterior view, body wide, not compressed laterally, maximum width of body at level of mandibular articulation. Median dorsal keel is absent. A single midgut loop, posterior intestinal caecum present. Few eggs in the brood pouch.  Headlarge, with well expressed, relatively long rostrum ( Fig. 6B). The anterior portion of headshield (= portion anterior to level of mandibular articulation) more than two times lager than posterior one, broadly rounded, with slightly projected rostral region ( Fig. 6C). A single major “head pore” as a ringed, sub-oval field of special cuticle located on a dorsal bubble. A small, circular lateral pore located at either side of major pore, closer to it ( Fig. 6D). Labrum fleshy body, with a medium-size median keel, terminating in a broadly rounded apex ( Fig. 6B) and with paired lateral horn-like projections ( Fig. 6E).  Valvesgenerally ovoid (VL/BL= 0.78–0.87), armature of posterior valve margin as in previous species ( Fig. 6F–H).  Postabdomenlarge (PL/BL= 0.41–0.44), relatively broad ( PH/PL= 0.48–0.56), with sub-parallel dorsal and ventral margins ( Fig. 6I). Distal anal embayment shallow. Armature of the preanal margin as a series of preanal teeth (NT=87–98); distalmost tip somewhat larger than others; small gap lacking any teeth at base of postabdominal setae; teeth in middle of preanal margin with sharp tips. Distalmost postanal teeth long, clustered; teeth at base of pre-claw portion mainly single ( Fig. 6J, arrows). Postabdominal setae as in previous species. Postabdominal claw relatively robust (CL/PL= 0.22–0.24); basal spines, first (distal) long (DS/CL= 0.30–0.47), second (basal) short (BS/CL= 0.13–0.22; BS/DS = 0.38–0.44).  Antenna I( Fig. 6K) relatively short (AL/BL = 0.10–0.11; AL/DA=2.86–3.42), triangular in cross section; protruding beyond tip of rostrum. Antennular sensory seta relatively short (about third of antenna I length), arising basally to antenna I middle. Nine bisegmented aesthetascs, with pointed teeth around them. Numerous short rows of relatively large denticles encircling antennular surface.  Antenna IIrelatively short; spine situated on proximal segment of exopod somewhat shorter than or equal to length of second segment ( Fig. 6L). Setae 0-0-3/1-1-3; spines 1-0-1/0-0-1.  Thoracic limbs( Fig. 7A–L) basically similar with those in  E. macracanthus, some differences described below. Limb I with IDL with a strong hook-like seta ( Fig. 7A–D), but not so large as in  E. macracanthus. In contrast to the latter, the smallest seta of IDL stronger in  E. longirostris. IDL with long distal spinules (4–11), long proximal spinules (3–15), short marginal spinules (1–11) and short basal spinules (0–12). On exopodite III seta 7 short, eight soft setae on inner limb portion ( Fig. 7G). On exopodite IV seta 1 relatively long ( Fig. 7I). On exopodite V setae 5–7 increasing in size distally ( Fig. 7J). Filter plate of gnathobase III, IV with 9 setae, and limb V with 8 setae.  Ephippial female, male.See Hann (1982).  Length.1.17–2.00 mm in our material.   Comments. Hann (1982)described two species,  E. longirostrisand  E. vernalis, and concluded that there are no evident morphological differences between them. Only ontogenetic changes were found to be different, as revealed by a statistical analysis of the instar variability. Unfortunately, such ontogenetic differences are difficult to interpret and diagnose. We concluded that the patterns of instar variability found by Hann (1982)lack discreteness when more populations are examined ( Bekker 2011). So, we believe that absence of any diagnostic traits of Hann's (1982)two taxa is due to their synonymy.   FIGURE 6.  Eurycercus longirostris, parthenogenetic female from CPR WDS, California, U.S.A. (A, C, D, F, G, H, K, L); Oliver Lake, Indiana, U.S.A. (B, E, I); Lake La Luna, in the crater of the volcano Nevado de Toluca, State of Mexico, Mexico (J). A, lateral view. B, head. C, head shield. D, head pores. E, labrum, ventral view. F, setae at anterior portion of valves. G, setae at postero-ventral portion of valve. H, armature of valve posterior margin. I, postabdomen. J, its distal portion. K, antenna I. L, antenna II. Scale bar denotes 1 mm (A); 0.1 mm (B-I).   FIGURE 7.  Eurycercus longirostris, limbs of parthenogenetic female from CPR WDS, California, USA (A–C, E–K); Lake La Luna, in the crater of the volcano Nevado de Toluca, State of Mexico, Mexico (D, L). A, limb I. B, its distal portion. C–D, inner distal lobe. E, limb II. F, distal armature of its gnathobase. G, limb III. H, its inner-distal portion. I, limb IV. J, limb V. K, distal armature of its gnathobase. L, limb VI. Scale bar denotes 0.1 mm. We found a small divergence of COIsequences among populations from distant points of the USA, including Indiana(the typelocality of  E. longirostris) and North Carolina(the typelocality of  E. vernalis). We found a separate sub-clade in Rhode Islandand Newfoundland, but its separation from  E. longirostriscould not be associated with Hann's (1982)separation of  E. longirostrisand  E. vernalis. Note that the opinion of Hann (1982)is influenced by Frey's (1982b)idea that populations of cladocerans in southern and northern regions of North America become reproductively isolated as their timing of gamogenesis diverges (in autumn in the North and in spring in the South), which leads to speciation. It is presently unclear if there are good examples of this mode of speciation in cladocera. Geographic clades are commonly found in cladocerans, but these are often West-East, not South-North ( Taylor et al.1998). For genetically differentiated northsouth species, it is unclear if differences in the timing of reproduction are a cause or an effect of speciation (Constanzo & Taylor 2010). Case 24.2.1 of ICZN (2000) proposed that "When the precedence between names or nomenclatural acts cannot be objectively determined, the precedence is fixed by the action of the first author citing in a published work those names or acts and selecting from them; this author is termed the "First Reviser"”. We followed this code, and  Eurycercus vernalis Hann, 1982is found by us to be a junior synonym of  E. longirostris Hann, 1982.   Distribution.It is a remarkable fact that the southernmost populations of  E. longirostrisoccur in Central Mexico ( Elías-Gutiérrez et al.1997, 2008) which is the southernmost portion of the Nearctic, while in nearby Neotropical Mexico, Belizeand Guatemala( Elías-Gutiérrez et al.2006, 2008), Central America and the West Indies ( Frey 1982a)  E. longirostrisis almost certainly absent. There is a big gap in the distribution of  Eurycercussouth to Central Mexico until Columbia (see Aranguren et al.2010; Bekker et al.2010). So, the taxa of  Eurycercusmight be subdivided into the Nearctic and the Neotropical. We know that  E. longirostris s.str.is widely distributed through whole U.S.A.and southern Canada( Hann & Karrow 1984; Chengalath 1987; Lemke & Benke 2004) and present even in Churchill ( Manitoba, Canada) ( Jeffery 2011) and the YukonTerritories (our data). But more Canadian populations need to be studied to further assess species diversity. At least, the molecular data suggests a more complicated situation (see two clades in the COIchapter in this article).   Ecology.It is widely distributed in water bodies of different types. We found that two "species" according to Hann (1982)appear to belong to a sole taxon. The range of thermal preferences of  E. longirostrisis quite wide as evidenced by a record from subarctic Churchill. CMN 19 20 USNM 181895, NHM 1980.371, 1980.372, USNM 181896 1 1 paratype [201,870,475,500] USNM 19 20 USNM 181894 1 allotype 2005-02-07 DJT Morei & M. Belyaeva & S. Ishida Canada 59.955 British Columbia 62 -132.024 19 20 DJT 3-618 1 British Columbia 1982-09-19 2006-08-16 1982-09-19 DGF M. M. Boucherle & Weir Channel & Churchill & Eiias-Gutierrez Canada Fish House Pond 58.672 Delta Marsh Field Station 62 -94.161 Boat 19 20 DGF 6770 1 Manitoba 2005-03-07 Ocean Pond & L. J. Hovind & M. Faustova Canada 47.4442 Newfoundland and Labrador 6 -53.4118 19 20 1 Newfoundland and Labrador 1984-10-31 DGF D. G. Frey Canada Harrietsfield Hgy. 19 20 DGF 7328 1 Nova Scotia [394,778,727,752] Canada 3 miles E Manitoba 19 20 1 Ontario 1974-08-29 1982-11-10 1974-08-29 DGF Trans-Canada Hwy & D. G. Frey & Algonquin Park Canada Pond on Opeongo Road 44.4226 Sydenham 6 -76.5559 Sydenham Lake 19 20 DGF 3660, DGF 6446, DGF 6490 1 Ontario 2005-02-07 DJT Squanga & M. Belyaeva & S. Ishida Canada 60.4478 Yukon 27 -133.603 19 20 DJT 3-624, DJT 3-625 1 Yukon 2011-08-08 DJT Anchorage & D. J. Taylor & A. A. Kotov & M. Ballinger & Medeiros & Ancourage United States of America 61.14558 Birch Lale 2 -149.9384 19 20 DJT20 1 Alaska 2001-01-05 AAK E. Gallo United States of America Lower Twin Lake Pond 19 20 AAK 2007-319 1 California 1965-12-09 DGF Creek Valley & Frey United States of America 40.5066 6 -121.3639 19 20 DGF 1726 1 California [405,774,1015,1040] Ponded Brooklet United States of America Colorado 19 20 1 Colorado 1975-02-09 DGF Frey United States of America 40.0816 6 -105.5412 19 20 DGF 1704 1 Colorado 2004-06-14 AAK Beach & D. J. Taylor & A. A. Kotov United States of America 41.5837 Connecticut 6 -71.7222 19 20 AAK 2005-234 1 Connecticut 2006-10-29 Hammond & S. Ishida & K. Kim United States of America 41.3647 Indiana 6 -85.6775 19 20 1 Indiana [484,1358,1124,1148] 1966-11-25 DGF Oliver & Frey United States of America 41.5724 6 -85.4051 19 20 DGF 2342 1 Indiana Hgy. United States of America Meddybemps Lake 19 20 1 Maine [206,1185,1196,1220] 1984-09-11 DGF Moosehorn Wildlife Refuge & Frey United States of America 19 20 DGF 7346 1 Maine 1966-11-08 DGF Sebago & D. G. Frey & Berner United States of America 43.778 68 -70.518 19 20 DGF 1911, DGF 1874 1 Maine 2004-06-26 Pequot Pond & A. A. Kotov & W. Piel United States of America Massachusetts 19 20 1 Massachusetts [251,1344,1304,1328] 1961-07-29 DGF Marl & D. G. Frey United States of America Douglas Lake 19 20 DGF 0295 1 Michigan 1966-07-07 DGF Hamilton & Frey United States of America 45.7551 6 -87.7854 19 20 DGF 1857 1 Michigan 1975-01-31 DGF Twin & Frey United States of America 43.3676 6 -86.1716 19 20 DGF 0303 1 Michigan [609,1067,1376,1400] United States of America Newton Lake 19 20 1 Minnesota 1979-08-08 DGF Ely & Frey United States of America 47.9768 6 -91.7273 19 20 DGF 5250 1 Minnesota State Road United States of America Pearl River 19 20 1 Mississippi 1974-09-05 DGF McCool & D. G. Frey & Roadside & Hwy United States of America 4 miles S of Indianola 19 20 DGF 3413 1 Mississippi [507,1172,1484,1508] 1978-03-13 DGF Frey United States of America 19 20 DGF 4583 1 Mississippi Otter Pond United States of America New Hampshire 19 20 1 New Hampshire [278,1432,1520,1544] 2004-06-24 AAK Sunapee & Pill & A. A. Kotov United States of America 43.4303 6 -72.0587 19 20 AAK 2005-255 1 New Hampshire [151,336,1556,1580] United States of America Sunapee Lake 19 20 1 New Hampshire [343,1432,1556,1580] 2004-06-24 AAK Brich Point & Piel & A. A. Kotov United States of America 19 20 AAK 2005-264, 265 1 New Hampshire [151,576,1592,1616] Fishpond & Atlantic United States of America New York 19 20 1 New York [583,1431,1592,1616] 1995-01-05 AAK Reservoir & Segers United States of America 19 20 AAK 1998-014 1 New York [1053,1131,1628,1652] United States of America Pond 19 20 1 New York 1995-08-05 AAK Brigantine National Wildlife Refuge & H. Segers & Round Pond United States of America 19 20 AAK 1998-016 1 New York 2004-12-06 AAK D. J. Taylor & A. A. Kotov United States of America 40.9857 Long Island 6 -72.2914 19 20 AAK 2005-223 1 Long Island 2005-07-06 DJT Lake Carolina & L. J. Hovind United States of America 35.475 North Carolina 71 -79.075 19 20 DJT 20-129 1 North Carolina 1958-08-18 DGF Pages & Patterson United States of America 35.1379 6 -79.4304 19 20 DGF 0050 1 Lake Carolina [515,1327,1772,1796] 1979-02-03 DGF D. G. Frey United States of America 35.5678 Panther Lake 6 -78.6955 19 20 DGF 3759 1 Lake Carolina 2004-11-06 DJT Swingle Road Pond & D. J. Taylor & A. A. Kotov United States of America 41.4154 Pennsylvania 6 -75.3162 19 20 DJT 20-004 1 Pennsylvania [151,1353,1844,1868] AAK Swingle Road Pond & D. J. Taylor & Kotov United States of America 41.4154 6 -75.3162 19 20 AAK 2005-219 1 Pennsylvania 2004-06-14 AAK Bowdish Reservoir & D. J. Taylor & A. A. Kotov United States of America 41.9242 Rhode Island 6 -71.7826 19 20 AAK 2005-236 1 Rhode Island United States of America Pool Tennessie Nat. Wildlife Ref. Reelfoot Lake 19 20 1 Tennessee [201,855,1952,1977] 1974-11-10 DGF Frey United States of America 19 20 DGF 3427 1 Tennessee 1975-03-26 DGF Crystal & D. G. Frey United States of America 44.7338 Vermont 6 -72.1539 19 20 DGF 2600 1 Vermont 1983-10-22 DGF Seattle & D. G. Frey United States of America 20 21 47.6784 Green Lake 6 -122.3381 19 20 DGF 6695 1 Washington [472,713,151,175] United States of America Slough 20 21 1 Washington 1978-06-27 DGF Camp & Olympic Peninsula & D. G. Frey United States of America Rain Forest Lake Quinault 20 21 DGF 4895 1 Washington 1956-06-23 DGF Fox & D. G. Frey United States of America 43.5822 Wisconsin 40 -88.919 20 21 DGF 0248 1 Wisconsin 1994-04-06 Nevado & M. Elias-Gutierrez Mexico 19.1036 Lake La Luna 7 -99.7556 Nevado de Toluca 20 21 1