Siconema

Luc, Pham Van, 2012, Two new species of Siconema (Drilonematoidea: Ungellidae) parasitic in earthworms in Vietnam, and systematic relationships as inferred from ribosomal sequence data, Zootaxa 3344, pp. 47-59 : 56-57

Key to females of the species of Siconema

1 Swelling at posterior followed by long, thin, conical part of tail (caudal organs distanced from tail extremity)............. 2

- Swelling at posterior followed by broadly conical part or short spike (caudal organs situated closely to tail extremity)..... 13

2 Head hook blades widely spaced......................................................................... 3

- Head hook blades situated closely to each other.............................................................. 4

3 Eggs prolate-ovoid, not protruding on poles, av. 70 x 32 µm in size, stoma reduced................................................................................................... S. neozelandicum Yeates & Spiridonov, 1996

- Eggs with knobs on both poles, 58 x 26 µm in size, stoma a protruding tube 2 µm high............. S. diducuncinum sp. n.

4 Ovary convoluted.....................................................................................5

- Ovary straight........................................................................................6

5 Body 1–2.8 mm long, slim except of swelling, eggshells thick with double corona and no caps..... S. siamense Timm, 1966

- Body 370–750 µm long, bloated, eggshells with single cup..................... S. baviense Spiridonov & Ivanova, 1998

6 Eggs 52– 53 x 31–33 µm in size, eggshells longitudinally wrinkled, margin of only pole marked by groove, caudal organs covered by hairs 30 µm long.......................................... S. lignophilae Spiridonov & Danilova, 1986

- Caudal organs not covered by hairs, eggs of different size and coat pattern........................................ 7

7 Body dramatically narrowing just posterior to caudal organs.................................................... 8

- Body gradually tapers posterior to caudal organs............................................................ 11

8 Body 1.3 mm long or shorter............................................................................ 9

- Body 1.8 mm or longer................................................................................ 10

9 Body 580–790 mµ long, caudal organs ca. 45 x 30 µm in size, hooks 7– 8 x 5–6 µm, pharynx 92–14 µm long, eggs moderately tuberculate with two tuberculate caps..................................... S. tonkinense Spiridonov & Ivanova, 1998

- Body 690–1230 µm long, caudal organs 42– 72 x 28–42 µm in size, hooks 10– 11 x 6–8 µm, pharynx 135–150 µm long, eggshells moderately mamillate with two tuberculate caps.................. S. hatayense Ivanova & Pham Van Luc, 1997

10 Body 1800–2400 µm long, eggshells av. 70 x 40 µm in size and 6–7 µm thick with rod-like ornamentation............................................................................................ S. ovicoronatum Timm, 1966

- Body 2.3–3.2 mm long, eggshells 54– 73 x 29–32 µm and 5 µm thick, with two polar caps.......... S. sinense Timm, 1966

11 Eggshells lemon-shaped, smooth, 50 x 28 µm in size................................... S. limonovatum Timm, 1966

- Eggshells ovoid, ornamented........................................................................... 12

12 Eggshells 52– 55 x 27–30 µm in size, surface papillate, single cap bearing ring-shaped structures, caudal organs 150 x 100 µm....................................................................... S bahli Spiridonov & Danilova, 1986

- Eggshells 50– 56 x 27–32 µm in size, surface cristate (covered by ridges), single cap tuberculate, caudal organs 100 x 80 µm................................................................... S. annamense Spiridonov & Danilova, 1986

13 Caudal organs broadly elliptical or circular................................................................ 14

- Caudal organ narrowly elliptical........................................................................ 24

14 Ovary tip at mid-body or at vulva........................................................................ 15

- Ovary tip in post-vulval region or near tail extremity......................................................... 16

15 Body 760–1340 µm long, eggshells 57– 62 x 31–35 µm in size, strongly echinate, no caps.... S. aculeatum Spiridonov, 1993

- Body 1700–2380 µm long, eggshells 62– 68 x 23–25 µm in size, finely mamillate with two polar knobs........................................................................................... S. aequicrassum Spiridonov, 1993

16 Ovary tip in post-vulval region.......................................................................... 17

- Ovary tip near tail extremity............................................................................ 23

17 Anus and rectum well developed, hooks displaced ventrally, eggshells 45– 52 x 20–25 µm in size, thinly mamillate, with two knob-like caps, occasionally one of the caudal organs reduced lacking spongy tissue.... S. inaequicrassum Spiridonov, 1993

- Anus and rectum poorly developed or absent, hooks displaced dorsally or apical, eggs of different size and coat pattern... 18

18 Hook blades fused on nearly whole length, eggshells 61– 62 x 28–30 µm in size with widely set acute pyramid-shaped spikes and two tuberculate caps................................. S. ovispicatum Spiridonov, Ivanova & Pham Van Luc, 2007

- Hook blades separated................................................................................. 19

19 Eggshells with polar differentiation...................................................................... 20

- Eggshells without polar differentiation.................................................................... 21

20 Eggshells 46– 49 x 24–26 µm in size, echinate, with a single, poorly differentiated cap................................................................................................. S. duplicoeca Spiridonov & Danilova, 1986

- Eggshells heavily mammilate, 56– 59 x 31–36 µm in size, with 2 convex, tuberculate caps.......................................................................................... S. laticaudatum Ivanova & Pham Van Luc, 1997

21 Eggshells 5 µm thick, with irregular hexagonal pattern and no polar differentiation, caudal organs 105 x 74 µm in size..................................................................................... S. ovicostatum Timm, 1966

- Eggshells thinner, with different ornamentation and polar differentiation, caudal organs of different size................ 22

22 Eggshells narrowly elliptical (52– 64 x 19–23 µm in size), moderately mamillate, caudal organs 80 x 38 µm in size....................................................................................... .. S. saccaturum Timm, 1966

- Eggshells av. 54 x 20 µm in size, narrowly rounded at ends, finely punctated, caudal organs 64 x 44 µm in size............................................................................................. S. micrurum Timm, 1966

23 Ovary convoluted, eggshells truncate-ovoid, 56– 61 x 31–34 µm in size, surface uneven, knobby, weakly tuberculate, 2 flat, tuberculate caps, caudal organs 150–193 x 114–125 µm in size................................. S. ovicallosum sp. n.

- Ovary slightly winding but making no loops, eggshells ovoid, 55– 60 x 27–29 µm in size, surface with rod-like pattern with delicate coating, 2 caps from flattened knobs, caudal organs 55–90 µm in diameter............ S. laotense Spiridonov, 1993

24 Eggshells without polar differentiation.................................................................... 25

– Eggshells with two polar caps, finely mamillate............................ S. mucrorimae Ivanova & Spiridonov, 1987

25 Ovary tip near tail extremity, eggshells av. 51 x 27 µm in size and 4 µm thick, heavily mamillate..................................................................................................... S ovimamillatum Timm, 1966

- Ovary tip near anterior end of caudal organs, eggs of different size and coat pattern................................ 26

26 Body ca. 2 µm long, pharynx 160–208 µm, hooks 12 x 11 µm in size, eggshells av. 58 x 34 µm in size, bearing irregular hexagonal pattern.................................................................. S. turgidum Timm, 1966

- Body 1.1–1.5 mm long, pharynx 80–100 µm long, hooks 9 x 8 µm in size, eggshells narrowly rounded at ends, av. 52 x 20 µm in size, finely mamillate.......................................................... S. micronchium Timm, 1966