Hastospiculum, Skrjabin, 1925

Ferreira-Silva, Cristiana, Alcantara, Edna P., Ávila, Robson W. & Silva, Reinaldo J., 2020, A new species of Hastospiculum Skrjabin (Spirurida: Diplotriaenidae) parasite of Xenodon merremii (Walger in Spix) (Serpentes: Dipsadidae) from Northeastern Brazil, Zootaxa 4878 (2), pp. 362-374 : 371

Key to the species of Hastospiculum

1 Left spicule longer than 1.5 mm .......................................................................... 2

- Left spicule less than 1.5 mm ............................................................................ 6

2 Left spicule longer than 4 mm, 8 pairs of pedunculate papillae (4 pre; 2 para; 2 postcloacal), no conical processes at the tail end......................................................................................... H. varani

- Left spicule 1.5–4 mm, tail end with conical processes........................................................ 3

3 Tail end with 1 conical process with small denticles, left spicule 2.35 mm, 5 pairs of pedunculate papillae (4 pre; 1 postcloacal), 3 pairs of sessile papillae...................................................................... H. setiferum

- Tail end with conical processes without small denticles....................................................... 4

4 Tail end with 1 pair of conical processes................................................................... 5

- Tail end with 2 pairs of conical processes, left spicule 2–3 mm long, 6 pairs of pedunculate papillae (5 pre; 1 postcloacal).......................................................................................... H. macrophallos

5 Left spicule spirally twisted, 1.94–2.27 mm, 8 pairs of pedunculate papillae (5 pre; 3 postcloacal) 1 pair sessile, and tail end with 1 pair of conical processes................................................................... H. spiralis

- Left spicule 1.84–2.2 mm, 7 pairs of pedunculate papillae (4 pre; 3 postcloacal), and tail end with 1 pair of conical processes........................................................................................ H. onchocercum

6 Lips larger, covering nearly the entire cephalic end, left spicule 1.2 mm ............................... H. uncertenum

- Lips not covering the entire cephalic end................................................................... 7

7 Tail end with conical processes.......................................................................... 8

- Tail end without conical processes........................................................................ 9

8 Left spicule 1.1 mm long, 6 pairs of pedunculate papillae (3 pre; 1 para; 2 postcloacal), 1 pair of conical processes...................................................................................................... H. gouldi

- Left spicule 1.3 mm long, 5 pairs of pedunculate papillae (4 pre; 1 postcloacal), 3 papillae adcloacal, 3 sessile pairs on the tail end, tail end with 1 pair of conical processes.................................................... H. venezuelense

9 Caudal alae surrounding the tail and connected............................................................. 10

- Caudal alae not surrounding the tail and unconnected........................................................ 11

10 Left spicule 1.01 mm, 6 pairs of pedunculate papillae (4 pre; 2 postcloacal)............................. H. bipinnatum

- Left spicule less than 1 mm, 6 pairs of pedunculate papillae (4 pre; 1 para; 1 postcloacal), 3 pairs sessile (1 adcloacal; 2 on tail end)....................................................................................... H. cubaense

11 Left spicule longer than 0.9 mm, 5 pairs of pedunculate papillae (3 pre; 1 para; 1 postcloacal)............. H. digiticaudum

- Left spicule 0.7–0.9 mm, 8 pairs of pedunculate papillae (3 pre; 1 para; 4 postcloacal), and 3 sessile papillae....................................................................................... Hastospiculum nordestinum n. sp.