Echeneibothrium multiloculatum Carvajal & Dailey, 1975 Carvajal & Dailey 1975
Creators: name: Franzese, Sebastián
name: Mutti, Leonardo D.
name: Tropea, Carolina
name: Ivanov, Verónica A.
Publisher: name: Zenodo
Year: 2022
Subjects: Biodiversity
Taxonomy
Animalia
Platyhelminthes
Cestoda
Rhinebothriidea
Echeneibothriidae
Echeneibothrium
Echeneibothrium multiloculatum

description: 3.2. Echeneibothrium multiloculatum Carvajal & Dailey, 1975 (Figs. 1B; 5C–D; 6; 7; 8A)    
 3.2.1. Emended description   
Based on whole mounts of 17 complete mature worms, serial sections of 1 mature proglottid and 2 scoleces, and SEM of 3 worms (23 specimens in total). Worms euapolytic, 2.7–5.6 mm (4.1 mm ± 0.9 mm, 14) long by 435–770 (528 ± 101, 9) wide, maximum width at level of scolex. Strobila composed of 15–23 (19 ± 2, 16) craspedote proglottids in number, 13–21 (17 ± 2, 16) immature, 2–3 (2 ± 0.3, 16) mature (Fig. 1B). Scolex with 4 stalked bothridia and apical myzorhynchus (Figs. 6A; 7A). Bothridia facially loculated, 300–485 (380 ± 49, 16) long by 220–295 (263 ± 31, 7) wide. Distal bothridial surface divided by medial longitudinal septum and 10–12 (11 ± 1, 6) transverse septa into 20–24 (23 ± 2, 6) loculi arranged in 2 columns with a single loculus at each end (Figs. 6A; 7A). Medial longitudinal septum extending from posterior margin of anteriormost loculus to anterior margin of posteriormost loculus (Fig. 6A). Anteriormost loculus 33–63 (46 ± 13, 8) long by 63–90 (74 ± 9, 8) wide, posteriormost loculus 15–28 (23 ± 6, 4) long by 33–60 (41 ± 13, 4) wide. Transverse septa and medial longitudinal septum formed distally by transverse and longitudinal muscle bundles, respectively, and uninterrupted underlying radial muscles with same orientation as adjacent radial muscles (Fig. 5C, D). Bothridial stalks 148–280 (204 ± 51, 9) long by 75–133 (107 ± 18, 9) wide. Neck 60–115 (83 ± 16, 13) wide. Myzorhynchus consisting of AMSP (sensu Caira et al. 1999) and AO, not observed in fully everted form, 65–150 (89 ± 25, 11) wide when partially retracted. AMSP retractable; AO invaginable with glandular cells (Fig. 6A). Proximal bothridial (Fig. 7C) and stalk surfaces covered by large gladiate spinitriches interspersed with capilliform filitriches. Distal bothridial surface covered by small gladiate spinitriches interspersed with capilliform filitriches (Fig. 7B). AMSP with acicular filitriches along its entire length, anteriormost region with band of gladiate spinitriches interspersed with acicular filitriches (Fig. 7D, E). AO surface not observed with SEM. Neck with acicular filitriches (Fig. 7F).  
Immature proglottids initially wider than long, becoming longer than wide with maturity. Subterminal mature proglottid 545–1010 (708 ± 138, 11) long (velum included) by 203–325 (273 ± 37, 11) wide; velum 13–25 (19 ± 4, 11) long, covering 1–2% (2 ± 0.4, 11) of adjacent proglottid. Terminal mature proglottid 815–1605 (1162 ± 208, 17) long by 190–345 (274 ± 43, 16) wide; width to length ratio 1: 3–7 (4 ± 1, 16) (Fig. 6B). Mature proglottids covered by capilliform filitriches. Testes oval, 14–19 (16 ± 2, 10) per proglottid, 35–65 (49 ± 8, 7, 35) long by 50–75 (63 ± 6, 7, 35) wide, arranged in 2 loosely columns anterior to cirrus sac (Fig. 6B), 1 layer deep in cross-section (Fig. 6C). Cirrus sac pyriform, 180–270 (216 ± 34, 10) long by 95–135 (118 ± 13, 10) wide, containing coiled cirrus covered by spinitriches. Vas deferens dorsal, highly coiled, entering dorsally at medial half of cirrus sac (Fig. 6D, F). Genital pores marginal, 41–53% (48 ± 3, 15) of proglottid length from posterior end.  
Vagina thick-walled, extending from ootype along midline of proglottid to anterior margin of cirrus sac, then laterally along anterior margin of cirrus sac to common genital atrium (Fig. 6B); vaginal sphincter and seminal receptacle absent (Fig. 6B, F). Ovary near posterior end of proglottid, H-shaped in dorso-ventral view (Fig. 6B), tetralobed in cross-section (Fig. 6E), symmetric (43% of specimens) or asymmetric (57% of specimens). Poral or aporal lobe longer than opposite lobe in asymmetric ovary, poral lobe 230–563 (424 ± 90, 13) long, aporal lobe 275–530 (430 ± 78, 13) long by 113–175 (148 ± 22, 8) wide at ovarian isthmus. Mehlis’ gland posterior to ovarian isthmus, 28–53 (38 ± 8, 7) in diameter (Fig. 6B). Vitelline follicles 10–38 (22 ± 5, 12, 60) long by 20–58 (36 ± 8, 12, 60) wide, in 8 total columns; 2 dorsal columns and 2 ventral columns on each lateral margin of proglottid (Fig. 6C–E), extending uninterrupted along entire proglottid (Fig. 6B, F). Uterus sacciform, occupying midline of proglottid, from level of ootype to anterior half of proglottid, without reaching its anterior margin (Fig. 6B). Two pairs of osmoregulatory ducts, 1 dorsal pair and 1 ventral pair; dorsal ducts narrower than ventral ducts (Fig. 6C–E).  
 3.2.2. Taxonomic summary   
 Type host: D. chilensis (Guichenot, 1848), yellownose skate (Rajiformes: Rajidae).   
 Additional host: D. brevicaudatus (Marini, 1933), short tail yellownose skate (Rajiformes: Rajidae).   
 Type locality: South Pacific Ocean, between latitudes 32 ◦ 28 ′ S and 37 ◦ 15 ′ S (between Papudo and Talcahuano, Chile).   
 Additional localities: Puerto Montt (41 ◦ 28 ′ S, 72 ◦ 56 ′ W), Chiloe´Island (42 ◦ 33 ′ S, 73 ◦ 56 ′ W), Calbuco (41 ◦ 46 ′ S, 73 ◦ 07 ′ W), Niebla / Valdivia (39 ◦ 52 ′ S, 73 ◦ 23 ′ W) and Vina ˜del Mar (33 ◦ 01 ′ S, 71 ◦ 33 ′ W), Chile. Mar de Ajo´(36 ◦ 34 ′ S, 54 ◦ 39 ′ W), Mar del Plata (38 ◦ 05 ′ S, 56 ◦ 58 ′ W) and Quequ´en (38 ◦ 35 ′ S, 58 ◦ 39 ′ W), Buenos Aires Province, Argentina. San Jorge Gulf (46 ◦ 13 ′ S, 66 ◦ 26 ′ W), Santa Cruz Province, Argentina. Tolhuin (54 ◦ 29 ′ S, 65 ◦ 59 ′ W) and Río Grande (53 ◦ 31 ′ S, 67 ◦ 48 ′ W), Tierra del Fuego Province, Argentina.
description: Published as part of Franzese, Sebastián, Mutti, Leonardo D., Tropea, Carolina & Ivanov, Verónica A., 2022, Morphological study of members of the genus Echeneibothrium (Cestoda: Rhinebothriidea: Echeneibothriidae) from rajiform skates of the Argentine Sea and analysis of the phylogenetic relationships within the family Echeneibothriidae, pp. 1-20 in Zoologischer Anzeiger 299 on pages 8-11, DOI: 10.1016/j.jcz.2022.05.002, http://zenodo.org/record/10375952