Anthocephalum miriamae, Sakai & Marques & Trevisan, 2025

Anthocephalum miriamae n. sp.,

Family Anthocephaliidae , order Rhinebothriidea

( Figs. 3B View FIGURE 3 , 4D–F View FIGURE 4 , 5F–J View FIGURE 5 , 6C–D View FIGURE 6 )

Type host: Hypanus longus (Garman) —Longtail stingray.

Type locality: Coast of Cebaco Island , Veraguas, Panama (7 ◦ 29’37.9”N, 81 ◦ 13’21.9”W) GoogleMaps .

Additional locality: Coast of Mariato , Veraguas, Panama (7 ◦ 36’06.3”N, 80 ◦ 59’33.7”W) GoogleMaps .

Site of infection: Spiral intestine.

Prevalence of infection: 50% (four of eight valves).

Specimens deposited: Holotype and one paratype ( MIUP H0086 ); three paratypes ( HWML 217950–217952 View Materials ); three paratypes ( LRP 11282–11284 ); and, two paratypes ( MZUSP 8060 View Materials a–b).

Etymology: This species honors Miriam Fukumitsu Sakai, mother of Lilian Sakai (first author), for her support and encouragement during graduation activities.

Description. [Based on 13 specimens: 9 whole mounts of mature worms, 1 scolex prepared for SEM and cross sections of 3 mature proglottids]: Worms euapolityc, 12.5–26.8 mm (n=9) long with 40–67 proglottids (n=9) in number, maximum width 721.5-1985 (n=4) at level of scolex ( Fig. 3B View FIGURE 3 ). Scolex ( Figs. 4E View FIGURE 4 , 5F View FIGURE 5 ) with four stalked bothridia, each one with 90–95 (n=2) marginal loculi and one oval apical sucker; apical sucker 57–66.5 (n=2) long by 48.5–76.5 (n=2) wide. Short cephalic peduncle present. Proximal surfaces of marginal loculi next to the bothridial rims covered with acicular filitriches and scolopate spinithriches ( Fig. 5G, H View FIGURE 5 ); bothridial rims and proximal surface of marginal loculi covered with acicular filitriches ( Fig. 5I View FIGURE 5 ); distal surface of bothridium covered with capiliform filitriches ( Fig. 5J View FIGURE 5 ).

Proglottids slightly craspedote. Immature proglottids wider than long, becoming longer than wide with maturity, 38–64 in number (n = 9) ( Fig. 3B View FIGURE 3 ). Mature proglottids ( Fig. 4F View FIGURE 4 ) 1402.5–2043.5 (n=6) long by 172–448 (n=6) wide, 1–4 in number (n = 9). 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. 4F View FIGURE 4 , 6C View FIGURE 6 ). Testes 45.5–72 (n=4) long by 35.5–58.5 (n=4) wide, 28–38 (n=4) in number. Cirrus-sac pyriform bent posteriorly, 114–161 (n=4) long by 60–89 (n=4) wide, containing coiled cirrus ( Fig. 4D View FIGURE 4 ). Cirrus armed with spinitriches. Genital pores lateral, irregularly alternating, 32.1–45.4% (n=6) of proglottid length from posterior end ( Fig. 4D, F View FIGURE 4 ). Ovary near posterior end of proglottid, H-shaped in frontal view ( Figs. 3B View FIGURE 3 , 4F View FIGURE 4 ), tetralobed in cross-section ( Fig. 6D View FIGURE 6 ), slightly asymmetrical, 388–620.5 (n=6) long by 111.5–270.5 (n=6) 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 ( Fig. 4D View FIGURE 4 ). Vitellarium follicular; vitelline follicles 22–75.5 (n=6) long by 8.5–18.5 (n=6) wide, arranged in two lateral bands, each band consisting of one dorsal and one ventral column of vitelline follicles, extending from near posterior margin of the first or second anterior-most row of testes to near posterior margin of proglottid, interrupted by genital pore and by ovary both dorsally and ventrally ( Figs. 4D, F View FIGURE 4 ). Uterus saccate, ventral, extending along median line of proglottid from near the Mehli’s gland to posterior margin of first or second anterior-most row of testes ( Fig. 4F View FIGURE 4 ).

Remarks: Anthocephalum miriamae n. sp. possesses a unique combination of morphological features. This new species, can be distinguishable from 15 of its congeners in number of proglottids [40–67 vs. 13–21 ( A. blairi ), 20–33 ( A. decrisantisorum ), 120–160 ( A. duszynskii ), 500–600 ( A. gracile ), 9–16 ( A. gravisi ), 17–29 ( A. haroldsoni ), 105–138 ( A. healyae ), 12–28 ( A. jensenae ), 7–10 ( A. mounseyi ), 86–120 ( A. odonnellae ), 11-30 ( A. ruhnkei ), 16–28 ( A. jeancadenati ), 9–15 ( A. alicae ), 80–110 ( A. cairae ), and 106–177 ( A. papefayei )]. In number of testes, Anthocephalum miriamae n. sp. possesses more testes than A. meadowsi and A. philruschi (28–38 vs. 15–25, 17–25, respectively) but fewer than A. centruturum (28–38 vs. 48–78). Anthocephalum miriamae n. sp. differs from A. hobergi based on the position of the genital pore on the proglottid (32–45% vs. 66–79%). The new species also differs in the arrangement of vitelline follicles by possessing a single dorsal and a single ventral column versus the 3–5 dorsal and 3–5 ventral columns of A. currani , 4–6 dorsal and 4–6 ventral columns of A. lukei , and 2–3 dorsal and 2–3 ventral columns of A. michaeli , A. kingae , and A. mattisi . Finally, Anthocephalum miriamae n. sp. differs from Anthocephalum machadoi as the former is proportionally larger, with different scolex shape (ellipsoid vs. deltoid, sensu Clopton (2004)), and associated with a distinct biogeographical region (Tropical Eastern Pacific vs. Tropical Western Atlantic), evidences that are corroborated by their phylogenetic positions based on molecular data.