Prochristianella cairae Schaeffner & Beveridge, 2012, n. sp.
Creators: name: Schaeffner, Bjoern C.
name: Beveridge, Ian
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Platyhelminthes
Cestoda
Trypanorhyncha
Eutetrarhynchidae
Prochristianella
Prochristianella cairae

description: Prochristianella cairae n. sp.
(Figs 1–3)
Material examined: 29 whole-mounts, 1 specimen used for SEM, tentacles detached from 1 specimen. Type-host: Chiloscyllium punctatum Müller & Henle, Brownbanded bambooshark (Orectolobiformes: Hemiscylliidae) (BO-53, BO-68, BO-295).
Additional hosts: Chiloscyllium indicum (Gmelin), Slender bambooshark (Orectolobiformes: Hemiscylliidae) (BO-482).
Type-locality: Mukah, Sarawak, Malaysia.
Site of infection: Spiral intestine.
Deposited specimens: Holotype (MZUM No 2012.09). Paratypes (MZUM Nos 2012.10–12; USNPC No 105180; LRP Nos 7838–7842; and SAM Nos AHC 35403–35407).
Etymology: This species is dedicated to Dr. Janine N. Caira. It represents the only species of Prochristianella for which microtriches could be observed.
Description: Cestodes small, euapolytic, 4.4–6.7 (5.6 ± 0.8; n = 12) mm long, with 8–9 (8; n = 7) segments (Fig. 1 A). Scolex acraspedote, 530–1,020 (690 ± 140; n = 12) long, almost uniform in width; pars bothrialis 140–200 (180 ± 20; n = 12) long; two oval bothria, with free margins, with V-shaped ridge (Fig. 3 A); proximal bothrial surface covered with serrate spathulate spinitriches (Fig. 3 D); pars vaginalis 310–740 (440 ± 120; n = 12) long; pars vaginalis and pars bulbosa covered in serrate spathulate spinitriches extending posteriorly to level of pars postbulbosa (Figs. 1 C, 3A, E); tentacle sheaths sinuous to almost straight (Fig. 1 A, C); pars bulbosa 220–330 (250 ± 40; n = 12) long, 110–190 (150 ± 30; n = 12) wide; prebulbar organs present; bulbs short, ovoid, 190–310 (230 ± 40; n = 12) long, 30–60 (50 ± 10; n = 12) in diameter (Fig. 1 B, C); bulb width: length ratio 1.0: 3.5–7.8 (5.4 ± 1.2; n = 12); retractor muscle originates at base of bulb; gland-cells inside bulbs present, few in number, in posteriormost part of bulb (Fig. 1 B, C); scolex ratio (pars bothrialis: pars vaginalis: pars bulbosa) 1.0: 1.6–4.1: 1.0–2.4 (1.0: 2.5 ± 0.7: 1.4 ± 0.4; n = 12). Pars postbulbosa short, 40–120 (70 ± 30; n = 7) long (Fig. 1 C).
Everted tentacles 600–650 (620 ± 30; n = 3) long; tentacle diameter 20 (n = 2) at base, 30–36 (34 ± 2; n = 5) at basal swelling, 18–23 (21 ± 2; n = 7) in metabasal region, 13–18 (16 ± 2; n = 4) distally. Armature heteroacanthous, heteromorphous; hooks solid (Figs. 2 A–D, 3C). Metabasal armature arranged in ascending half rows; hook rows begin on antibothrial surface of tentacle, terminate on bothrial surface (Fig.2 A, B), without prominent space between hook files 1 and 1’ on antibothrial surface of tentacle (Fig. 2 A); half spirals with 9 hooks, decreasing to 8 anteriorly (Figs. 2 B, 3B); hooks 1(1’) uncinate, 4–5 (4; n = 10) long, base 3 (3; n = 10) long; hooks 2(2’) uncinate, slightly larger, with shorter base, 4–5 (5; n = 10) long, base 2–3 (2; n = 10) long, becoming more falcate distally; hooks 3(3’) uncinate, slightly larger, 5–6 (5; n = 7) long, base 2–3 (3; n = 7) long, becoming more falcate distally; hooks 4(4’) falcate, with short base, largest hooks of principle rows, 5–6 (6; n = 10) long, base 2 (2; n = 10) long; hooks 5(5’) falcate, smaller, 3 (3; n = 4) long, base 1 (1; n = 4) long; hooks 6(6’)–9(9’) uncinate, smaller, inconspicuous, 1–2 (1; n = 15) long, base 1 (1; n = 15) long.
Characteristic basal armature present (Figs. 2 D, 3B), with enlarged hooks posterior to basal swelling; hooks at very base of tentacle uncinate, 3–4 (4; n = 3) long, base 3–4 (3; n = 3) long; hooks posterior to basal swelling larger, falcate, 5–6 (5; n = 3) long, base 1 (1; n = 3) long (Fig. 3 B). Basal swelling prominent, with 6–10 (8 ± 1; n = 7) hook rows; hooks showing transition into ‘V’-formations towards bothrial surface; transition from uncinate to falcate with recurved tips towards bothrial surface; largest hooks on bothrial surfaces falcate with recurved tips, 3–4 (3; n = 3) long, base 1–2 (2; n = 3) long (Fig. 2 D).
Segments acraspedote; mature segments longer than wide, 900–1,970 (1,290 ± 280; n = 12) long, 180–370 (260 ± 60; n = 12) wide (Fig. 1 D); genital pores alternate irregularly, in posterior half of segment (Fig. 1 D); cirrus sac ovoid, thick-walled, 70–125 (90 ± 21; n = 5) long, 80–138 (108 ± 20; n = 5) wide (Fig. 1 D); cirrus unarmed; internal and external seminal vesicles absent. Testes in single layer, in two longitudinal columns, 43–57 (49 ± 5; n = 7) in number, 32–45 (38 ± 4; n = 7) preporal, 10–13 (11 ± 1; n = 7) postporal, 55–70 (63 ± 6; n = 12) long, 30–38 (34 ± 3; n = 12) wide, exclusively preovarian, absent in region of cirrus sac (Fig. 1 D). Vagina enters genital atrium from posterior aspect; seminal receptacle sub-circular, c. 18 (n = 1) in diameter; ovary bilobed in dorso-ventral view; ovarian lobes elliptic, 125–178 (152 ± 21; n = 6) long, 43–65 (53 ± 9; n = 6) wide (Fig. 1 D); Mehlis’ gland posterior to ovarian isthmus, 38–45 (43 ± 4; n = 3) in diameter; vitelline follicles circumcortical, 23–30 (28 ± 2; n = 15) in diameter; uterus median, tubular, extending to anteriormost part of segment (Fig. 1 D); uterine pore not observed.
Gravid segments longer than wide, 1,460–2,370 (1,860 ± 310; n = 6) long, 300–520 (450 ± 90; n = 6) wide (Fig. 1 E); uterus saccate; eggs round, thin-shelled, non-operculate, non-embryonated, 26–33 (28 ± 2; n = 31) in diameter; surface with hair-like structures.
Remarks: This species belongs within the genus Prochristianella, since it possesses a slender, acraspedote scolex with two oval bothria, prebulbar organs and gland-cells within the elongate bulbs, retractor muscles inserting at the base of each bulb, a typical heteroacanthous armature with hooks of each principle row increasing and then decreasing in size towards the bothrial surface, and a basal swelling with a distinctive basal armature. However, the present specimens differ from other species of Prochristianella in having hooks 1 and 1’ of the metabasal armature not being widely separated. The most obvious morphological feature of P. c a i r a e n. sp. are the enlarged microtriches covering the scolex, reaching from the distal bothrial surfaces posterior to the level of the pars postbulbosa. The microthrix shape resembles that of serrate spathulate spinitriches (sensu Chervy 2009). Of all currently known species of Prochristianella, four taxa show prominent and microscopically visible microtriches on the scolex, namely P. clarkeae, P. h i s p i d a, P. multidum and P. thalassia. The species described here differs from all of them by possessing more segments, hooks in the principle rows of the metabasal armature being dissimilar in number and a different arrangement of hooks on the basal swelling of each tentacle. Prochristianella cairae n. sp. also possesses a scolex much larger than those of P. clarkeae, P. h i s p i d a and P. multidum. Moreover, the bulbs of P. cairae n. sp. are smaller and narrower than those of P. clarkeae and P. thalassia and testes are more numerous than those of P. multidum and P. thalassia. Specimens of this species were obtained from a single locality in Malaysian Borneo from the spiral intestines of two species of Chiloscyllium Müller & Henle. We therefore consider this species to be highly host specific, only infecting bamboosharks of the family Hemiscylliidae.
description: Published as part of Schaeffner, Bjoern C. & Beveridge, Ian, 2012, Prochristianella Dollfus, 1946 (Trypanorhyncha: Eutetrarhynchidae) from elasmobranchs off Borneo and Australia, including new records and the description of four new species, pp. 1-25 in Zootaxa 3505 on pages 3-7, DOI: 10.5281/zenodo.208605