Anthocephalum machadoi, Sakai & Marques & Trevisan, 2025

Anthocephalum machadoi n. sp.,

Family Anthocephaliidae , order Rhinebothriidea

( Figs. 3A View FIGURE 3 , 4A–C View FIGURE 4 , 5A–E View FIGURE 5 , 6A–B View FIGURE 6 )

Type host: Hypanus guttatus (Bloch & Schneider) – Longnose stingray.

Type locality: Coast of Maceió, Alagoas, Brazil (09°40’25.32”S, 035°44’07.08”W) GoogleMaps .

Additional locality: Colares, Pará, Brazil (01 ◦ 00’33.88”S, 048 ◦ 16’47.28”W) GoogleMaps .

Site of infection: Spiral intestine.

Prevalence of infection: 44.9% (31 of 69 valves).

Specimens deposited: Holotype ( MZUSP 8076 View Materials ) GoogleMaps and 11 paratypes ( MZUSP 8054a–e, 8055, 8056a–b, 8057, 8058, 8059 ); GoogleMaps 12 paratypes ( HWML 217938–217949 View Materials ); GoogleMaps and, 12 paratypes ( LRP 11270–11281 ). GoogleMaps

Etymology: This species honors Dr. Denis Jacob Machado for his contribution to the systematics of cestodes through his expertise in bioinformatics.

Description. [Based on 37 specimens: 29 whole mounts of mature worms, 2 scolexes prepared for SEM and cross sections of 6 mature proglottids]: Worms apolytic, 5.8–13.6 mm (n=29) long with 20–45 proglottids (n=29) in number, maximum width 439.5–761 (n=10) at level of scolex ( Fig. 3A View FIGURE 3 ). Scolex ( Figs. 4B View FIGURE 4 , 5A View FIGURE 5 ) with four stalked bothridia, each one with 76–96 (n=10) marginal loculi and one oval apical sucker; apical sucker 33.6–45.1 (n=4) long by 29.5–32.7 (n=4) wide. Short cephalic peduncle present. Proximal surfaces of marginal loculi next to the bothridial rims covered with acicular filitriches and scolopate spinithriches ( Fig. 5B, C View FIGURE 5 ); bothridial rims and proximal surface of marginal loculi covered with acicular filitriches ( Fig. 5D View FIGURE 5 ); distal surfaces of bothridia covered with capiliform filitriches ( Fig. 5E View FIGURE 5 ).

Proglottids slightly craspedote. Immature proglottids wider than long, becoming longer than wide with maturity, 16–42 in number (n = 29) ( Fig. 3A View FIGURE 3 ). Mature proglottids ( Fig. 4A View FIGURE 4 ) 1,066–1,749.6 (n=15) long by 125.2–225.3 (n=15) wide, 1–4 in number (n = 29). Testes arranged in two columns from near anterior margin of proglottid to level of genital pore, and 1 row-deep in cross-section ( Figs. 4A View FIGURE 4 , 6A View FIGURE 6 ). Testes 35.5–72.5 (n=17) long by 28.1–55.8 (n=17) wide, 35–46 (n=17) in number. Cirrus-sac pyriform, bent posteriorly, 75.8–121.3 (n=8) long by 43.8–112.5 (n=8) wide, containing coiled cirrus ( Fig. 4C View FIGURE 4 ). Cirrus armed with spinitriches. Genital pores lateral, irregularly alternating, 27.6–35.5% (n=15) of proglottid length from posterior end ( Fig. 3A View FIGURE 3 , 4A View FIGURE 4 ). Ovary near posterior end of proglottid, H-shaped in frontal view ( Figs. 4A View FIGURE 4 ), tetralobed in cross-section ( Fig. 6B View FIGURE 6 ), slightly asymmetrical, 229.6–432 (n=16) long by 68–165.8 (n=16) 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. 4C View FIGURE 4 ). Vitellarium follicular; vitelline follicles 13.6–33.1 (n=17) long by 6.5–17.3 (n=17) wide, arranged in two lateral bands, each band consisting of one dorsal and one ventral column of vitelline follicles, extending from near anterior margin of the anterior-most row of testes to near posterior margin of proglottid, interrupted by genital pore and ovary both dorsally and ventrally ( Figs. 4A, C View FIGURE 4 ). 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. 4A View FIGURE 4 ).

Remarks: Anthocephalum machadoi n. sp. is distinguishable among the 24 other species of the genus Anthocephalum by its distinct combination of morphological features which include: 35–46 testes, 76–96 loculi, a total length of 5.8–13.6 mm, and vitelline follicles organized into two lateral bands with one dorsal and one ventral column each. In comparison with Anthocephalum blairi Herzog & Jensen, 2018 , Anthocephalum gravisi Herzog & Jensen, 2018 , Anthocephalum haroldsoni Herzog & Jensen, 2018 , and Anthocephalum papefayei , the new species possesses more marginal loculi (76–96 vs. 65–73, 43–52, 41–57, and 45–60; respectively). On the other hand, Anthocephalum machadoi n. sp. posses fewer marginal loculi compared to Anthocephalum gracile (Wedl, 1855) Ruhnke, 1994 , Anthocephalum healyae Ruhnke, Caira & Cox, 2015 , Anthocephalum lukei Ruhnke and Seaman, 2009 , Anthocephalum meadowsi Ruhnke, Caira & Cox, 2015 , Anthocephalum odonnellae Ruhnke, Caira & Cox, 2015 , Anthocephalum philruschi Ruhnke, Caira & Cox, 2015 , Anthocephalum cairae , and Anthocephalum hobergi (Zamparo, Brooks & Barriga, 1999) Marques & Caira, 2016 (76–96 vs. 116–121, 150–171, 107–138, 98–134, 135–159, 200–219, 197–198, and 100; respectively).

Anthocephalum machadoi n. sp. differs from Anthocephalum duszynskii Ruhnke, 1994 and Anthocephalum mounseyi Herzog & Jensen, 2018 , in its total length (5.8–13.6 mm vs. 18–31 and 2.6–3.4 mm, respectively), and from Anthocephalum decrisantisorum Ruhnke, Caira & Cox, 2015 , Anthocephalum jensenae Ruhnke, Caira & Cox, 2015 , Anthocephalum ruhnkei Herzog & Jensen, 2018 , and Anthocephalum centrurum , in number of testes (35–46 vs. 17–24, 14–20, 22–34, and 48–78, respectively). In comparison with Anthocephalum alicae , A. machadoi n. sp. possesses more proglottids in number (20–45 vs. 9–15, respectively).

There are only five species— Anthocephalum currani Ruhnke & Seaman, 2009 , Anthocephalum michaeli Ruhnke & Seaman, 2009 , Anthocephalum jeancadenati Boudaya, Neifar & Euzet, 2018 , Anthocephalum kingae (Schmidt, 1978) Ruhnke & Seaman, 2009 , and Anthocephalum mattisi — that closely resembles A. machadoi n. sp. in number of marginal loculi, number of testes, total length, and proglottid number. However, they can be distinguished based on the position and number of the vitelline follicles. Anthocephalum machadoi n. sp. possesses vitelline follicles organized into two lateral bands with single dorsal and ventral column. In contrast, A. michaeli , A. jeancadenati , A. kingae , and A. mattisi also possess vitelline follicles in two lateral bands but with 2–3 dorsal and ventral columns. Finally A. currani possesses vitelline follicles in two lateral bands with 3–5 dorsal and ventral columns.