Anthocephalum nataliae n. sp.

(Figs. 3C, 6E–F, 7A–C, 8A–E)

Type host: Styracura schmardae (Werner) – Chupare stingray.

Type locality: Coast of Tobacco Caye, Stann Creek, Belize (16 ◦ 54’15.2”N, 88 ◦ 03’38.2”W).

Site of infection: Spiral intestine.

Prevalence of infection: 20% (one of five valves).

Specimens deposited: Holotype (HWML 217953) and five paratypes (HWML 217954–217958); six paratypes (LRP 11285–11290); and, six paratypes (MZUSP 8061a–f).

Etymology: This species honors Dr. Natalia Luchetti for her contributions to cestodes taxonomy.

Description. [Based on 28 specimens: 17 whole mounts of mature worms, 9 scolexes prepared for SEM and cross sections of 2 mature proglottids]: Worms euapolityc, 4,6–8.1 (n=17) long with 13–21 proglottids (n=17) in number, maximum width 661.5–902 (n=3) at level of scolex (Fig. 3C). Scolex (Figs. 7B, 8A) with four stalked bothridia, each one with 58–66 (n=3) marginal loculi and one oval apical sucker; apical sucker 23.5–57 (n=12) long by 39–60.5 (n=12) wide. Short cephalic peduncle present. Proximal surfaces of marginal loculi next to the bothridial rims covered with acicular filitriches and scolopate spinithriches (Fig. 8B, C); bothridial rims covered with acicular filitriches (Fig. 8D); distal surface of bothridium covered with capiliform filitriches (Fig. 8E).

Proglottids slightly craspedote. Immature proglottids wider than long, becoming longer than wide with maturity, 12–20 in number (n = 17) (Fig. 3C). Mature proglottids (Fig. 7A) 1195.3–1751 (n=11) long by 153–204.8 (n=11) wide, 1 in number (n = 17). Testes arranged in two columns from near anterior margin of proglottid to anterior margin of genital pore, and 1 row-deep in cross section (Figs. 7A, 6E). Testes 40–51.3 (n=9) by 32.8–50 (n=9) wide, 36–50 (n=9) in number. Cirrus-sac pyriform slightly bent posteriorly, 100.5–187.3 (n=5) long by 71–95 (n=5) wide, containing coiled cirrus (Fig. 7C). Cirrus armed with spinitriches. Genital pores lateral, irregularly alternating, 29.4–42.1% (n=10) of proglottid length from posterior end (Fig. 3C, 7A). Ovary near posterior end of proglottid, H-shaped in frontal view (Figs. 3C, 7A), tetralobed in cross-section (Fig. 6F), slightly asymmetrical, 238.5–528 (n=9) long by 82.3–137.5 (n=9) wide; ovarian bridge near middle of ovary. Mehli’s gland immediately posterior to ovarian bridge. Vagina thick-walled, sinuous, extending medially in proglottid from ootype to anterior margin of cirrus-sac, then laterally to open into genital atrium anterior to cirrus, expanded proximally (Fig. 7C). Vitellarium follicular; vitelline follicles 21.5–48.3 (n=6) by 5.3–18 (n=6), arranged in 2 lateral bands, each band consisting of one dorsal and one ventral column of vitelline follicles, extending from posterior margin of first or second anterior-most row of testes to anterior margin of the ovary to near posterior margin of proglottid, interrupted by genital pore and partially by ovary both dorsally and ventrally (Figs. 7A, C). Uterus saccate, ventral, extending along median line of proglottid from near the ovarian bridge to posterior margin of first or second anterior-most row of testes (Fig. 7A).

Remarks: Anthocephalum nataliae n. sp. can be distinguished from 16 of its 26 congeners in number of proglottids (13–21 vs. 35–70 A. currani, 120–160 A. duszynskii, 500-600 A. gracile, 105–133 A. healyae, 28–56 A. lukei, 30–40 A. meadowsi, 23–41 A. michaeli, 7–10 A. mounseyi, 86–120 A. odonnellae, 27–40 A. philruschi, 80– 110 A. cairae, 33–50 A. kingae, 35–40 A. mattisi, 106–177 A. papefayei, 53–98 A. hobergi and, 40–67 A. miriamae). Furthermore, A. nataliae n. sp. differs from A. blairi, A. decrisantisorum, A. haroldsoni, A. jensenae, and A. ruhnkei by possessing more testes (36–50 vs. 10–15, 17–24, 25–32, 14–20, and 22–34, respectively).

Anthocephalum nataliae n. sp. closely resembles A. jeancadenati, A. alicae, A. gravisi, and A. machadoi in total length, number of proglottids, and number of testes. However, A. nataliae n. sp. possesses a unique vitelline follicle arrangement: two lateral bands each with one dorsal and one ventral column. This contrasts with A. jeancadenati, which possesses two lateral bands with 2–3 dorsal and 2–3 ventral columns each, and A. alicae, with two lateral bands each with two dorsal and two ventral columns. Lastly, Anthocephalum nataliae n. sp. differs from A. machadoi by possessing fewer marginal loculi (58–66 vs. 76–96, respectively) and from A. gravisi by possessing a uterus that extends to the anterior margin of the proglottid.