Prochristianella scholzi, 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 : 14-17

Prochristianella scholzi n. sp.

( Figs 9 & 10 )

Material examined: 35 whole-mounts.

Type-host: Taeniura lymma 1 (sensu Naylor et al. 2012) ( Rajiformes : Dasyatidae ) (KA-416).

Additional host: T. lymma (BO-80, BO-86).

Type-locality: Kunak, Sabah, Malaysia.

Additional localities: Semporna, Sabah, Malaysia; and Tanjung Batu, East Kalimantan, Indonesia.

Site of infection: Spiral intestine.

Deposited specimens: Holotype ( MZUM No 2012.01). Paratypes in ( MZUM Nos 2012.02–03; MZB Nos Ca 165–167; LRP Nos 7829–7834; SAM Nos AHC 35395–35399; and USNPC No 105183).

Etymology: This species is dedicated to Dr. Tomáš Scholz, who has contributed previously to trypanorhynch systematics.

Description: Cestodes small; mature specimens 3.6–6.0 (4.9 ± 0.8; n = 10) mm long with 7–9 (8 ± 1; n = 15) segments; gravid specimens 6.5 (n = 2) mm long with 9 (n = 2) segments. Scolex acraspedote, 950–1,465 (1,240 ± 153; n = 13) long ( Fig. 9 A, D); maximum width at pars bothrialis, 280–330 (306 ± 18; n = 8) wide; pars bothrialis 150–220 (180 ± 21; n = 13) long; two sub-circular bothria, 175–200 (188 ± 10; n = 7) long, 205–240 (219 ± 10; n = 11) wide, with thick, free margins, notched posteriorly, V-shaped ridge present in some specimens ( Fig. 9 A); pars vaginalis 450–920 (716 ± 138; n = 13) long; Pintner’s cells present in mid-line ( Fig. 9 D); tentacle sheaths sinuous to almost straight, strongly coiled if contracted; transverse striations present in pars vaginalis ( Fig. 9 A, D); pars bulbosa 470–590 (520 ± 38; n = 13) long, 165–225 (194 ± 18; n = 13) wide; prebulbar organs present; bulbs elongate, thick-walled, 455–570 (506 ± 38; n = 11) long, 60–80 (70 ± 5; n = 11) wide ( Fig. 9 A, C, D), extend into pars proliferans in some specimens; bulb width: length ratio 1.0: 6.3–9.3 (7.4 ± 0.9; n = 11); retractor muscle inserts at base of bulb; gland-cells present, few, very small ( Fig. 9 C, D), surrounding retractor muscle to mid-bulbar region, in some specimens into anterior third of bulb; scolex ratio (pars bothrialis: pars vaginalis: pars bulbosa) 1.0: 2.6–5.5: 2.4–3.7 (1.0: 4.0 ± 0.8: 2.9 ± 0.4; n = 13). Pars postbulbosa very short, up to 35 (9 ± 12; n = 15) long.

Fully everted tentacles 450–610 (536 ± 56; n = 9) long, with prominent basal swelling; diameter 24–25 (25 ± 1; n = 3) at base, 33–38 (35 ± 2; n = 4) at basal swelling, 25–28 (27 ± 1; n = 4) in metabasal region, 25–26 (25 ± 1; n = 3) distally. Metabasal armature heteroacanthous, heteromorphous; hooks hollow; hook rows consist of 10 hooks in posterior metabasal region ( Fig. 9 E), decrease to 9 hooks per principle row anteriorly; rows start on antibothrial surface of tentacle, terminate on bothrial surface ( Fig. 10 B, C); distinct space between hooks 1 and 1’ ( Fig. 10 C); first four rows of principle rows with two smaller hooks posterior to hooks 1(1’) ( Fig. 10 C); hooks 1(1’) uncinate, with elongate base, 11–14 (13 ± 1; n = 6) long, base 7–10 (8 ± 1; n = 6) long; hooks 2(2’) larger, falcate, with narrower base, 12–15 (14 ± 1; n = 7) long, base 4–6 (5 ± 1; n = 4) long; hooks 3(3’) slightly smaller, falcate, 12–15 (13 ± 1; n = 9) long, base 4–6 (4 ± 1; n = 9) long; hooks 4(4’) smaller, falcate, 8–10 (9 ± 1; n = 5) long, base 3–4 (3 ± 1; n = 5) long; hooks 5(5’) larger, falcate, 12–16 (14 ± 1; n = 6) long, base 4 (n = 6) long; hooks 6(6’) smaller, spiniform, 5–6 (5 ± 1; n = 6) long, base 2–3 (3; n = 6) long; hooks 7(7’) smaller, spiniform, 4–5 (4; n = 4) long, base 2 (n = 4) long; hooks 8(8’) spiniform, 4–5 (4 ± 1; n = 3) long, base 2 (n = 3) long; hooks 9(9’) slightly smaller, spiniform, 3–4 (4 ± 1; n = 2) long, base 2 (n = 2) long; hooks 10(10’) slightly smaller, spiniform, 3 (n = 2) long, base 2 (n = 2) long.

Characteristic basal armature present ( Fig. 10 A–C); first rows of hooks enlarged on bothrial surface, falcate, 13–14 (14; n = 2) long, base 4–6 (5 ± 1; n = 2) long; basal hooks on antibothrial surface smaller, uncinate, 6–9 (7 ± 1; n = 3) long, base 4–5 (4 ± 1; n = 3) long; next 4–5 rows of hooks spiniform, bases reduced, 6–9 (7 ± 1; n = 8) long; basal swelling with 5 rows of hooks; increasing in size towards enlarged billhook on bothrial surface ( Fig. 10 A, B); billhooks form single file ( Fig. 10 B), largest billhooks in second and third row on basal swelling, 7 (n = 2) long, base 3 (n = 2) long, height 8 (n = 2); hooks on antibothrial surface spiniform, become falcate to almost uncinate anteriorly ( Fig. 10 C); transition to metabasal armature occurs at about hook row 17 ( Fig. 10 A, B).

Segments acraspedote; first segments wider than long; first mature segments elongate, 170–320 (247 ± 51; n = 8) long, 110–205 (147 ± 37; n = 8) wide ( Fig. 9 A); late mature segments 985–2,020 (1,381 ± 336; n = 8) long, 130–230 (174 ± 38; n = 8) wide ( Fig. 9 B); genital pores unilateral, in posterior half of segment ( Fig. 9 A, B); cirrus sac oval to sub-circular, thick-walled, 68–105 (86 ± 13; n = 6) long, 70–100 (88 ± 12; n = 6) wide; internal and external vesicles absent; cirrus unarmed. Testes arranged in two columns, anterior to ovary, in intervascular space, 53–71 (62 ± 5; n = 14) in number, 41–57 (48 ± 5; n = 14) anterior to genital pore, 12–18 (15 ± 2; n = 14) posterior to genital pore, 48–63 (52 ± 4; n = 17) long, 33–39 (35 ± 2; n = 17) wide ( Fig. 9 B). Vagina thin-walled, enters genital atrium from posterior aspect; seminal receptacle c. 20 (n = 2) in diameter; ovary at posterior extremity of segment, bilobed in dorso-ventral view; ovarian lobes elongate, 183–258 (207 ± 26; n = 8) long, 29–40 (33 ± 4; n = 8) wide ( Fig. 9 B); Mehlis’ gland present between ovarian lobes, 25–38 (30 ± 6; n = 4) in diameter; vitelline follicles circumcortical, 20–23 (21 ± 1; n = 10) long, 13–15 (14 ± 1; n = 10) wide; uterus tubular, median, extends to anterior extremity of segment; uterine pore not observed.

Gravid segments 1,655–1,980 (1,845 ± 169; n = 3) long, 175–305 (227 ± 69; n = 3) wide; uterus extends to anteriormost extremity; cirrus sac sub-circular, 118 (n = 1) long, 108 (n = 1) wide; ovarian lobes 155–160 (158 ± 4; n = 2) long, 36–38 (37 ± 1; n = 2) wide; vitelline follicles 30–38 (35 ± 2; n = 10) long, 25–30 (27 ± 2; n = 10) wide.

Remarks: The present specimens are allocated to the genus Prochristianella , since they possess the typical, generic characteristics. The most significant features of this species are the smooth scolex, thick-walled bulbs with very few, tiny gland-cells, unilateral genital pores and a tentacular armature with enlarged basal hooks, rows of billhooks on the basal swelling and 10 hooks per half spiral row, decreasing in number to 9 hooks per row further anteriorly. The principle hook rows in the metabasal region have small hooks 4(4’), as described above for P. kostadinovae , which represents the most similar species within the genus. Prochristianella scholzi n. sp. differs from P. kostadinovae in its possession of enlarged basal hooks, two additional hooks posterior to hooks 1(1’) in the most proximal part of the metabasal armature, smaller hooks 1(1’)–6(6’), hooks 2(2’) and 3(3’) without a recurved tip, a much wider basal swelling than the remainder of the tentacle and a transition into the metabasal armature at about hook row 17. Moreover, P. scholzi n. sp. has smaller bothria, Mehlis’gland and vitelline follicles, but much more elongated ovarian lobes. Prochristianella scholzi n. sp. is described from stingrays of the genus Taeniura Müller & Henle from three localities in Sabah (Malaysian Borneo) and East Kalimantan (Indonesian Borneo).

Figures

FIGURE 9. Prochristianella scholzi n. sp. from Taeniura lymma 1 (sensu Naylor et al. 2012). A. Partial specimen. B. Mature segment. C. Bulb. D. Scolex. E. Outlines of metabasal hooks. Abbreviations: cs, cirrus sac; gc, gland-cells; mg, Mehlis’ gland; ov, ovary; rm, retractor muscle; sr, seminal receptacle; t, testis; vit, vitelline follicle.

FIGURE 10. Prochristianella scholzi n. sp. from Taeniura lymma 1 (sensu Naylor et al. 2012). Tentacular armature. A. Basal and metabasal regions, external surface. B. Basal and metabasal regions, bothrial surface. C. Basal and metabasal regions, antibothrial surface; note opposing surface to (B) of the same tentacle.