Description

Description (Fig. 1) Based on 10 male and 12 female specimens from Charadrius dubius, Weymouth, Dorset, England (BMNH 1936.8.17.124 - 140). General. Trunk elliptical, almost ovoid, narrowing posteriorly. Transverse vessels of lacunar system form dense reticulum of large polygons. Proboscis cylindrical, situated at angle to axis of trunk. Proboscis armament consists of 19 - 20 longitudinal rows of 13 - 14 (12) hooks; first 8 (9) hooks longest, next 2 smaller and last 3 hooks smallest; all hooks with posteriorly directed roots. Neck short (partly or completely withdrawn in some specimens), trapezoidal. Proboscis receptacle doublewalled. Lemnisci band-shaped (bifurcate in single specimen), longer than proboscis receptacle. Male. Trunk 2.4 - 5.2 long, 1.0 - 1.64 wide. Proboscis (completely everted in only 2 specimens) 0.56 - 0.62 long, 0.16 wide. Length of first 8 hooks – blade 32 - 42 µm, root 32 - 44 µm; length of next 2 hooks – blade 29 µm, root 25 - 32 µm; length of last 3 hooks – 25 - 27 (29) µm, root 13 - 22 µm. Neck (in 2 specimens) c. 0.1 long. Proboscis receptacle 0.70 - 0.95 long and 0.16 - 0.25 wide. Lemnisci 1.0 - 2.6 long, 0.09 - 0.15 wide. Testes oval to spherical, 0.30 - 0.80 long, 0.23 - 0.41 wide, situated in tandem and slightly overlapping one another, in middle region of trunk. Cement glands 6 in number, of different lengths, 0.30 - 0.95 long, situated immediately posterior to hind testis. Duct of cement glands 0.35 - 0.65 long. Genital bursa (everted in single specimen) 0.25 long, 0.30 wide. Female. Trunk 2.64 - 7.0 long, 1.21 - 2.9 wide. Proboscis (completely everted in only 2 specimens) 0.66 - 0.7 long, 0.17 - 0.19 wide. Length of first 8 (9) hooks – blade 37 - 44 (49) µm, root 34 - 54 µm; length of next 2 hooks – blade 34 - 39 µm, root 27 - 39 µm; length of last 3 hooks blade – 17 - 29 µm, root 15 - 27 µm. Neck 0.15 - 0.17 long. Proboscis receptacle 0.72 - 1.1 long, 0.24 - 0.27 wide. Lemnisci 1.0 - 1.9 long, 0.1 - 0.13 wide. Female genital tract c. 1.2 - 1.45 long. Vagina provided with 2 sphincters. Genital pore slightly subterminal, at 0.06 - 0.12 from posterior end of trunk. Fully-developed eggs were observed in 4 specimens (5.1 - 7.0 long). Eggs elongate-oval, shuttle-shaped, with polar prolongations, 91 - 134 (135) × 25 - 42 µm. Additional data. (based on 2 male specimens from C. hiaticula, BMNH 1928.2.17.91). Trunk 4.0 - 4.7 in length, 1.4 - 1.55 wide. Proboscis 0.48 - 0.5 long. Proboscis armament consists of 20 longitudinal rows of 11 - 12 hooks in each row. Measurements and morphology of hooks are similar to material from Dorset. Neck very short (40 - 63 µm long). Testes spherical, 0.60 - 0.65 long, 0.75 - 0.87 wide. Cement glands 0.55 - 1.0 long.

Common Names

Taxonomic Hierarchy

Kingdom: Animalia

Phylum: Acanthocephala

Class: Palaeacanthocephala

Order: Polymorphida

Family: Plagiorhynchidae

Genus: Plagiorhynchus

Species: Plagiorhynchus crassicollis (Villot, 1875)