Echeneibothrium multiloculatum Carvajal & Dailey, 1975

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, Zoologischer Anzeiger 299, pp. 1-20 : 8-11

publication ID	https://doi.org/ 10.1016/j.jcz.2022.05.002
publication LSID	lsid:zoobank.org:pub:2B1478CC-D510-4637-A784-D5283821EF7D
DOI	https://doi.org/10.5281/zenodo.10375948
persistent identifier	https://treatment.plazi.org/id/039EC10C-5B01-FFFD-FFE5-D62AFC6CF838
treatment provided by	Felipe
scientific name	Echeneibothrium multiloculatum Carvajal & Dailey, 1975
status

Treatment

3.2. Echeneibothrium multiloculatum Carvajal & Dailey, 1975 View in CoL ( Figs. 1B View Fig ; 5C–D View Fig ; 6 View Fig ; 7 View Fig ; 8A View Fig )

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 View Fig ). Scolex with 4 stalked bothridia and apical myzorhynchus ( Figs. 6A View Fig ; 7A View Fig ). 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 View Fig ; 7A View Fig ). Medial longitudinal septum extending from posterior margin of anteriormost loculus to anterior margin of posteriormost loculus ( Fig. 6A View Fig ). 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 View Fig ). 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 View Fig ). Proximal bothridial ( Fig. 7C View Fig ) 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 View Fig ). AMSP with acicular filitriches along its entire length, anteriormost region with band of gladiate spinitriches interspersed with acicular filitriches ( Fig. 7D, E View Fig ). AO surface not observed with SEM. Neck with acicular filitriches ( Fig. 7F View Fig ).

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 View Fig ). 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 View Fig ), 1 layer deep in cross-section ( Fig. 6C View Fig ). 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 View Fig ). 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 View Fig ); vaginal sphincter and seminal receptacle absent ( Fig. 6B, F View Fig ). Ovary near posterior end of proglottid, H-shaped in dorso-ventral view ( Fig. 6B View Fig ), tetralobed in cross-section ( Fig. 6E View Fig ), 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 View Fig ). 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 View Fig ), extending uninterrupted along entire proglottid ( Fig. 6B, F View Fig ). Uterus sacciform, occupying midline of proglottid, from level of ootype to anterior half of proglottid, without reaching its anterior margin ( Fig. 6B View Fig ). Two pairs of osmoregulatory ducts, 1 dorsal pair and 1 ventral pair; dorsal ducts narrower than ventral ducts ( Fig. 6C–E View Fig ).

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) GoogleMaps , 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 GoogleMaps . 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 GoogleMaps . San Jorge Gulf (46 ◦ 13 ′ S, 66 ◦ 26 ′ W), Santa Cruz Province, Argentina GoogleMaps . Tolhuin (54 ◦ 29 ′ S, 65 ◦ 59 ′ W) and Río Grande (53 ◦ 31 ′ S, 67 ◦ 48 ′ W), Tierra del Fuego Province, Argentina GoogleMaps .