Eocyzicus phytophilus, Tippelt & Schwentner, 2018

Tippelt, Lisa & Schwentner, Martin, 2018, Taxonomic assessment of Australian Eocyzicus species (Crustacea: Branchiopoda: Spinicaudata), Zootaxa 4410 (3), pp. 401-452 : 427-430

Eocyzicus phytophilus sp. nov.

( Figs. 13 and 14 )

Eocyzicus lineage Y Schwentner et al., 2014, 2015b

Etymology. The species name is derived from Ancient Greek and translates as "prefer plants" which relates to its occurrence in well vegetated water bodies.

Type locality. Queensland, Bulloo River catchment, swamp near Thargomindah Station , 28°03´12.5´´S, 143°47´11.5´´E.

Type material. Holotype. Male (AM P.89579, GenBank KC583943 ).

Allotype. Female (AM P.89581, GenBank KC583945 ).

Paratypes. 3 males (AM P.89580, GenBank KC583944 ; AM P.89582, GenBank KC583946 ; AM P.89583, GenBank KC583947 ), 1 female (AM P.89584, GenBank KC583948 ), collected by M. Schwentner, S. Richter and B. V. Timms, 26-II-2011.

Further material examined. New South Wales: 3 males (AM P.89568, AM P.89571, AM P.89572) , 3 females (AM P.89569, AM P.89570, AM P.89573) Grassy pool north of Yantabulla , 29°19´04.8´´S, 145°00´31.5´´E, 20-I- 2010 ; 1 female (AM P.89564) Beverly's Pool, Bloodwood Station , 29°32´12.0´´S, 144°51´16.1´´E, 19-II-2010 ; 1 female (AM P.89566) Small lake on east boundary, north site of road, Muella Station , 29°31´38.5´´S, 145°00´43.7´´E, 20-II-2010 ; 1 female (AM P.89565) Small lake on east boundary, south site of road, Muella Station , 29°31´54.1´´S, 145°01´02.4´´E, 20-II-2010 ; South Australia: 1 male (AM P.89574) , 1 female (AM P.89575) Old small dug out 105 km east of Marla , 27°10´00.2´´S, 134°33´07.2´´E, 11-III-2011 ; 1 female (AM P.89577) Vegetated clear water swamp 43 km west of Oodnadatta , 27°20´38.9´´S, 135°08´40.3´´E, 11-III-2011 .

Description. Holotype male ( Fig. 13a, c and d ). Carapace. 2.9 mm high, 4.7 mm long, height/length ratio 0.62; height without "crowded" growth lines 2.7 mm, length without "crowded" growth lines 4.5 mm; shape oval; dorso-posterior corner clearly present; twelve growth lines, of these eleven "non-crowded" and one "crowded"; umbo small, hemispheric, growth lines absent ( Fig. 13a ).

Head. Condyle rounded, section between condyle and external eye contour concave; eye bulge small, compound eye oval; obtuse angle between head and rostrum, anterior margin of rostrum convex; transition between anterior and ventral margin angular ( Fig. 13c ). Antennule with 23 lobules, widely arranged; reaches to 11th antennary segment. Antenna with twelve antennary segments, middle antennary segment anteriorly with four spines.

Thorax. 21 thorax segments, of these 19 "complete" and two "incomplete" ( Fig. 13d ); dorsal spines beginning at 7th thorax segment, 13 thorax segments with dorsal spines; one dorsal spine at each thorax segment, first dorsal spine same size as following one, last dorsal spine smaller than preceding one, last "complete" thorax segment with dorsal spine ( Fig. 13d ).

Telson. 13 telsonic spines, of these three enlarged, telsonic spines end after base of apex; telson symmetric; telsonic filaments situated at fourth telsonic spine. Furca with ten setae, longer than proximal part of furca; small spine before row of spinules present, spinules short ( Fig. 13d ).

Allotype female ( Fig. 13b, e and f ). Carapace. 4.8 mm long, height/length ratio 0.6; height without "crowded" growth lines 2.5 mm; length without "crowded" growth lines 4.1 mm; 13 growth lines, of these eleven "noncrowded" and two "crowded" ( Fig. 13b ).

Head. Section between condyle and external eye contour straight; eye bulge absent, compound eye round ( Fig. 13e ). Antennule with 16 lobules, closely arranged; reaches to fifth antennary segment. Antenna with eleven antennary segments, middle antennary segment anteriorly with five spines.

Thorax. Twelve thorax segments with dorsal spines; last dorsal spine larger than preceding one; last "complete" thorax segment without dorsal spine ( Fig. 13f ).

Telson. 17 telsonic spines, of these two enlarged; telsonic filaments situated between third and fourth telsonic spine. Furca with three setae, shorter than proximal part of furca ( Fig. 13f ).

Ovigerous flagella situated at 9th and 10th thorax segment.

Variability. Males. Carapace. 2.7–4.0 mm high, 4.5–6.4 mm long, height/length ratio 0.59–0.65; height without "crowded" growth lines 2.6–3.7 mm; length without "crowded" growth lines 4.3–6.3 mm; dorso-posterior corner clearly present or nearly absent; 12–20 growth lines, of these 11–18 "non-crowded" and up to five "crowded"; umbo small or large, hemispheric, growth lines present or absent.

Head. Section between condyle and external eye contour concave or straight; eye bulge absent or present, if present small or large, compound eye oval or round; acute or obtuse angle between head and rostrum ( Fig. 14a ). Antennule with 16–23 lobules, closely or widely arranged; reaches to 8th–12th antennary segment ( Fig. 14b ). Antenna with 11–13 antennary segments, middle antennary segment anteriorly with three to six spines.

Thorax. 19–22 thorax segments, of these 19–21 "complete" and up to two "incomplete" ( Fig. 14e ); dorsal spines beginning at 5th–8th thorax segment, 13–16 thorax segments with dorsal spines; first dorsal spine smaller than, same size as or larger than following one, last dorsal spine smaller than or same size as preceding one, last "complete" thorax segment with or without dorsal spine ( Fig. 14e ).

Telson. 13–21 telsonic spines, of these one to four enlarged, telsonic spines end before, at or after base of apex; telsonic filaments situated between second and fifth telsonic spine. Furca with 4–14 setae, as long as or longer than proximal part of furca ( Fig. 14e ).

Variability. Females. Carapace. 2.9–4.5 mm high, 4.7–6.9 mm long, height/length ratio 0.6–0.65; height without "crowded" growth lines 2.5–4.1 mm, length without "crowded" growth lines 4.1–6.5 mm; dorso-posterior corner clearly present or nearly absent; 13–20 growth lines, of these 11–17 "non-crowded" and up to nine crowded"; umbo small or large, growth lines present or absent.

Head. Section between condyle and external eye contour concave or straight; eye bulge absent or present, if present small or large, compound eye oval or round; acute to obtuse angle between head and rostrum, anterior margin of rostrum concave, straight or convex, transition between anterior and ventral margin rounded or angular. Antennule with 12–18 lobules; closely or widely arranged; reaches to 4th –7th antennary segment. Antenna with 10– 13 antennary segments, middle antennary segment anteriorly with four to six spines.

Thorax. 20–22 thorax segments, of these 19–21 "complete" and one or two "incomplete"; dorsal spines beginning at 7th –11th thorax segment, 10–14 thorax segments with dorsal spines; first dorsal spine smaller than or same size as following one; last dorsal spine smaller, same size or larger than preceding one, last "complete" thorax segment with or without dorsal spine.

Telson. 17–22 telsonic spines; of these one to five enlarged, telsonic spines end at or after base of apex; telsonic filaments situated between third and fifth telsonic spine. Furca with three to twelve setae, shorter than, as long as or longer than proximal part of furca.

Differential diagnosis. Eocyzicus phytophilus sp. nov. and its putative sister species E. parvus sp. nov. are morphologically – for example by the total number of growth lines – as well as genetically clearly differentiated ( Tables 1 and 2; Schwentner et al., 2014). Therefore, E. phytophilus sp. nov. can be delimitated as a species following the PSC sensu Wheeler & Platnick (2000), ESC (Wiley & Mayden, 2000) and BSC (Mayr, 1942). Morphologically E. phytophilus sp. nov. resembles most closely Eocyzicus ubiquus sp. nov. They can be distinguished by the length of spinules (long in Eocyzicus ubiquus sp. nov. and short in E. phytophilus sp. nov.), the total number of growth lines on the carapace and the number of telsonic spines ( Tables 1 and 2).

Distribution and ecology. This species occurs in vegetated fresh, clear and turbid water bodies and shows a sympatric distribution with E. ubiquus sp. nov., E. richteri sp. nov., Eocyzicus parvus sp. nov., E. armatus sp. nov., E. parooensis and E. argillaquus and rarely occurs syntopically with the latter.

Figures

FIGURE 13. Eocyzicus phytophilus sp. nov. a, carapace of male holotype (AM P.89579). b, carapace of female allotype (AM P.89581). c, head of male holotype. d, telson of male holotype. e, head of female allotype. f, telson of female allotype. ce = compound eye, co = condylus, ds = dorsal spine, fu = furca, gl = growth lines, is = „incomplete" thorax segments, md = mandible, ro = rostrum, sp = spinules, tf = telsonicfilaments, ts = telsonic spines, um = umbo.

FIGURE 14. Eocyzicus phytophilus sp. nov. male paratype (AM P.89582). a, rostrum (left antenna removed). b, antennule. c, second right clasper, arrow indicates the scales at the tip of the movable finger. d, detail of the tip of the movable finger of second right clasper.e,telson, arrow indicates "incomplete" thorax segment.f, distal part of furca.A1 = antennules, ds = dorsal spine, fu = furca, lp = large palpus, mf = movable finger, ro = rostrum, sc = scales, sp = spinules, tf = telsonic filaments, ts = telsonic spines.