Prochristianella cairae, Schaeffner, Bjoern C. & Beveridge, Ian, 2012

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, Zootaxa 3505, pp. 1-25 : 3-7

publication ID	https://doi.org/ 10.5281/zenodo.208605
publication LSID	lsid:zoobank.org:pub:E1B0DD55-07DC-4994-9327-62EF0E0107A1
DOI	https://doi.org/10.5281/zenodo.6166961
persistent identifier	https://treatment.plazi.org/id/F20B094A-FFDE-4179-37C9-241DFB6FFB1A
treatment provided by	Plazi
scientific name	Prochristianella cairae
status	sp. nov.

Treatment

Prochristianella cairae View in CoL n. sp.

( Figs 1–3 View FIGURE 1 View FIGURE 2 View FIGURE 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 View FIGURE 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 View FIGURE 3 A); proximal bothrial surface covered with serrate spathulate spinitriches ( Fig. 3 View FIGURE 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 View FIGURE 1 C, 3A, E); tentacle sheaths sinuous to almost straight ( Fig. 1 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 2 A, B), without prominent space between hook files 1 and 1’ on antibothrial surface of tentacle ( Fig. 2 View FIGURE 2 A); half spirals with 9 hooks, decreasing to 8 anteriorly ( Figs. 2 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 1 D); genital pores alternate irregularly, in posterior half of segment ( Fig. 1 View FIGURE 1 D); cirrus sac ovoid, thick-walled, 70–125 (90 ± 21; n = 5) long, 80–138 (108 ± 20; n = 5) wide ( Fig. 1 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 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 View FIGURE 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 .