Epacanthion

Guilherme, Betânia Cristina, Silva, Maria Cristina Da & Esteves, André Morgado, 2009, Description of a new species of Epacanthion (Thoracostomopsidae, Nematoda) from Brazil and a modified key for species identification *, Zootaxa 2096, pp. 99-108 : 105-106

Key to species of Epacanthion

1 Spicules without gubernaculum.................................................................................................................................... 2

- Spicules with gubernaculum......................................................................................................................................... 3

2 Spicules long (more 100 µm), one pre-anal supplement ................................................................... E. agubernaculus

- Spicules short (less 100µm), without pre-anal supplement ............................................................................... E. oliffi

3 Spicules short, 2-5 or fewer anal diameters long.......................................................................................................... 4

- Spicules long, 3 or more anal diameters long............................................................................................................. 14

4 Pre-anal supplement present ......................................................................................................................................... 5

- Pre-anal supplement absent ........................................................................................................................................ 12

5 Nine to 14 small, setose pre-anal supplements ............................................................................................................. 6

- Only one pre-anal supplement ...................................................................................................................................... 7

6 Distance between tips of apical teeth about equal to length of mandibular columns, which are short, stout and paral- lel....................................................................................................................................................... E. multipapilatum

- Mandible with tips of apical teeth much closer together than length of mandibular columns, which are slender and diverge at apex ................................................................................................................................................. E. oweni

7 Distance between tip of apical mandibular hooks either clearly much greater or much less than length of mandibular columns ......................................................................................................................................................................... 8

- Distance between apical mandibular hooks apparently about same as length of mandibular columns ......................... ........................................................................................................................................................... E. brevispiculum

8 Distance between tip apical mandibular hooks much greater than length of mandibular columns.............................. 9

- Distance between apical mandibular hooks much less than length of mandibular columns ...................................... 10

9 Spicules 1–2 anal diameters (59 µm), gubernaculum a triangular plate, dorsal onchia much smaller than other two, 12 pairs of cervical setae in male, 4 in female ............................................................................................ E. mawsoni

- Spicules 0–75 anal diameters (34 µm), gubernaculum reduced, onchia apparently unequal, male with 12 cervical setae (female unknown) ........................................................................................................................... E. pellucidum

10 Spicules 2–5 anal diameters (80 µm), gubernaculum present (37 µm) lip not striated..................... E. microdentatum

- Spicules 1 anal diameter (90 µm), lip flaps striated ................................................................................................... 11

11 Small species (1.5–2.0 mm long), male head hirsute, cephalic setae maximum length 30 µm, inserted above cephalic arch, posterior rim of cephalic capsule crenelated (indistinct) ................................................................... E. galeatum

- Larger species (2.2–2.9 mm long), male head hirsute, cephalic setae maximum length 50 µm, longer than head diameter, inserted just below cephalic arch, posterior rim of cephalic capsule not crenelated ............ E. exploratoris

12 Male head hirsute with many subcephalic and cervical setae .......................................................... E. enoploidiforme

- Male head not hirsute.................................................................................................................................................. 13

13 Mandibles very long and slender, mandibular columns about twice as long as distance between apical teeth ............. ..................................................................................................................................................... E. gorgonocephalum

- Mandibles not long and slender, distance between mandibular teeth less, or only slightly longer (1.2x), than mandibular columns...................................................................................................................................... E. georgei

14 Tail long, 4 or more anal diameters, spicules of equal length, may be annulated ...................................................... 15

- Tail short, only 3 anal diameters, spicules always annulated, may be of unequal length........................................... 18

15 Spicules>200 µm (3–3. 5 anal diameters), always annulated.................................................................................... 16

- Spicules 130–175 µm (3–3. 5 anal diameters) long, not annulated............................................................................ 19

16 Larger species, males and females more than 4 mm long, α value 27–34, onchia nearly reaching cephalic arch, inner cephalic setae long, 40 µm.......................................................................................................................................... 17

- Smaller species, 2.9–3.1 mm long, α value 117–19, onchia small, not reaching cephalic arch, inner cephalic setae very short, 28 µm ....................................................................................................................................... E. durapelle

17 Tail setae numerous (>10 setae)................................................................................................................. E. buetschlii

- Tail setae sparse(only two medial setae)................................................................................................... E. stekhoveni

18 Spicules of unequal ......................................................................................................................................... E. nadjae

- Spicules equal in length ............................................................................................................................... E. saveljevi

19 Head blunt anteriorly, mandibular columns parallel, diverging strongly at apex, male supplement 90 µm in front of anus ................................................................................................................................................... E. brevispiculosum

- Head pointed anteriorly, mandibular columns parallel, male supplement 132–158 µm in front of anus....................... ............................................................................................................................................................... E. polysetosum