Mazocraeidea Bychowsky, 1957

Kamio, Yusuke & Nitta, Masato, 2022, New Records of Gemmaecaputia corrugata (Monogenea: Chauhaneidae) from Sphyraena forsteri (Sphyraenidae) off Yomitan Town, Okinawa-jima Island, Southern Japan, Species Diversity 27 (1), pp. 83-90 : 84-88

publication ID	https://doi.org/ 10.12782/specdiv.27.83
persistent identifier	https://treatment.plazi.org/id/03C587D9-FF8B-FFE2-FF98-FEB718DB1743
treatment provided by	Felipe
scientific name	Mazocraeidea Bychowsky, 1957
status

Treatment

Order Mazocraeidea Bychowsky, 1957 View in CoL

Suborder Gastrocotylinea Lebedev, 1972 Family Chauhaneidae Euzet and Trilles, 1960 View in CoL Subfamily Opisthogyninae Unnithan, 1962 Genus Gemmaecaputia Tripathi, 1959 View in CoL Gemmaecaputia corrugata Tripathi, 1959 View in CoL ( Figs 1 View Fig , 2 View Fig )

Gemmaecaputia corrugata Tripathi, 1959: 109–111 View in CoL , fig. 50; Unnithan 1962: 320–323, figs 7–12; Yamaguti 1963: 196, fig. 345; Lebedev 1976: 24, 26; Lebedev 1986: 125, 128, fig. 147; Zhang et al. 1999: 236–237, fig. 8-133; Zhang et al. 2001: 259–260, fig. 19-3; Zhang et al. 2003: 121; Liu and Chen 2012: 209, unnumbered fig.

Redescription. Body ( Fig. 1 View Fig ) elongated 1100–2625 (1630, n=10) long including haptor, 250–525 (369, n=9) wide at level of ovary. Haptor ( Fig. 1 View Fig ) fan-shaped, symmetrical, 50–120 (74, n=6) long, 300–470 (398, n=6) wide, with four pairs of gastrocotylid clamps. Clamps pedunculated. First, second and third clamps on left side slender in dorsal view ( Fig. 1 View Fig ; clI–III), the remaining clamps round shape; first clamp (length×width) on the right side 62.5–87.5×62.5– 82.5 (82.5×76, n=8), second 62.5–85×57.5–87.5 (80×76.4, n=8), third 57.5–87.5×62.5–82.5 (80.4×76.4, n=8), fourth 52.5–82.5×60–75 (76.1×71, n=8); first clamp on left side 70–102.5×35–55 (75×64.6, n=8), second 90–105×50–55 (91.1×52.9, n=8), third 62.5–102.5×35–65 (94.6×50.7, n= 7), fourth 52.5–80×50–72.5 (92.9×50.8, n=8). Clamp ( Fig. 2D, E View Fig ) consisting of pair of antero-lateral sclerite and postero-lateral sclerite, ventral mid-sclerite, dorsal mid-sclerite and pair of accessory sclerites. Antero-lateral sclerite and postero-lateral sclerite thin and long. Small sclerites from proximal end of postero-lateral sclerite toward inside. Ventral mid-sclerite long, dorsal mid-sclerite short and rough, both mid-sclerite bifurcated on top. Accessory sclerites sickle-like at the end, from lateral sclerite to top of mid-sclerite ventrally.

Mouth ( Fig. 1 View Fig ) opening anterior terminal. Pair of oral suckers ( Fig. 1 View Fig ) elliptical, 17.5–32.5×40–52.5 (24.4×48.8, n=9). Small spheroidal gland cells ( Fig. 1 View Fig ) rice grainshaped, 14–19 (16, n=3) in number around the mouth. Pharynx ( Fig. 1 View Fig ) subspherical, lying behind oral sucker, 25–42.5×30–55 (32.5×40, n=9). Esophagus ( Fig. 1 View Fig ) narrow, without lateral diverticula. Intestinal bifurcation ( Fig. 1 View Fig ) at level of anterior end of vitellarium. Intestinal ceca ( Fig. 1 View Fig ) blind, extending to base of haptor, with numerous lateral diverticula.

Common genital pore ( Figs 1 View Fig , 2B View Fig ), between pharynx and intestinal bifurcation. Genital atrium unarmed. Testes ( Figs 1 View Fig , 2C View Fig ) of irregular shape; each 27.5–87.5×37.5–100 (49.6×54.9, n=8), intercecal in posterior half of body prop- er, 16–19 (17, n=8) in number, in two irregular columns; longer left row extending to level posterior of ovary; shorter right row reaching mid-level of ovary. Vasa efferentia ( Fig. 2C View Fig ) between the two rows of testes, with thin walls, uniting medially between rows of testes before connecting to vas deferens. Vas deferens ( Figs 1 View Fig , 2C View Fig ) muscular, coming from level of anterior testes, traveling anteriorly along midline on ventral side of body, winding strongly, entering base of penis. Penis ( Fig. 2B View Fig ) elongate to fusiform, 62.5–120×10–20 (85×16.9, n=9), muscular, without sclerotized armature. Atrium musculinus ( Fig. 2B View Fig ) wide, irregular shape, associated with anterior end of common genital pore.

Ovary ( Fig. 1 View Fig ) inverted J-shaped, located in posterior part of body, on posterior side of the right row of testes, 200–320 (250, n=7) in length along curve, 60–110 (82.5, n=7) at greatest width. Subtriangular proximal lobe ( Figs 1 View Fig , 2A View Fig ) at proximal end of ovary 87.5–137.5×45–75 (113.6×59.2, n= 6), many small cells existed. Oviduct ( Fig. 2A View Fig ) arising from distal end of ovary, connecting to vitelline duct to form ovovitelline duct, and looping anteriorly on dorsal side of body. Ovo-vitelline duct ( Fig. 2A View Fig ) connecting to vaginal duct anteriorly, continuing to oötype and uterus. Uterus ( Figs 1 View Fig , 2A View Fig ) running anteriorly along body midline, dorsal to vas deferens, opening anterior to the penis in common genital pore. Vaginal pore ( Fig. 2C View Fig ) unarmed, 10–15 (11.7, n=3) in diameter, ventral in mid-body, between bifurcation of intestinal ceca and anterior testes. Vaginal duct ( Fig. 2C View Fig ) ventral to testes, extending along midline from vaginal pore to base of oötype. Genito-intestinal canal ( Fig. 2A View Fig ) originating from oötype posteriorly, extending posteriorly to left intestinal cecum. Transverse vitelline ducts ( Fig. 1 View Fig ) joining ventrally at level of distal end of ovary. Vitelline duct ( Fig. 2A View Fig ) running ventrally to oötype. Vitellarium ( Fig. 1 View Fig ) extended from behind bifurcation of intestinal ceca to base of haptor. Eggs not observed.

Material examined. 10 specimens ( MPM 21744a–e) .

Locality. Off Yomitan Town (26°21′51.4″N, 127°43′09.2″E) in Okinawa-jima island, Southern Japan GoogleMaps .

Host. Sphyraena forsteri Cuvier, 1829 ( Perciformes : Sphyraenidae ).

Site of infection. Gill filament.

Intensity. Thirteen monogeneans infected one host fish.

Representative DNA sequences. DDBJ (DNA Data Bank of Japan) accession numbers LC623879 View Materials (28S rDNA) and LC623880 View Materials (cox1) .

Remarks. The present specimens collected from the Sphyraena forsteri in Japanese waters show the diagnostic morphological characteristics of Gemmaecaputia provided by Young (1968) and agree approximately with the descriptions of G. corrugata by Tripathi (1959) and Unnithan (1962). Gemmaecaputia corrugata is distinguished from the other congeneric, G. tripathii as follows: large number of small spheroidal gland cells around the mouth (14–19 in G. corrugata vs. 13–14 in G. tripathii ) and the extension of the vitellaria from behind the bifurcation of intestinal ceca to the base of the haptor vs extending from the penis to slightly posterior to the intestinal ceca in G. tripathii (see Tripathi 1959; Unnithan 1962; Gupta and Krishna 1980).

There were some points to be corrected in the redescription of G. corrugata by Unnithan (1962) and Zhang et al. (2001). Unnithan (1962) reported the uterus of G. corrugata as being located on the ventral side of the testes and the vaginal duct running along the dorsal side of the testes, and Unnithan (1962) and Zhang et al. (2001) described the vaginal pore on the dorsal surface. However, the present study shows that the uterus is on the dorsal side of the testes, and the vaginal pore and the vaginal duct are on the ventral side of the testes. Also, Tripathi (1959) described the vaginal pore as ventral. The description by Unnithan (1962) and Zhang et al. (2001) most likely misrepresented the vaginal pore as dorsal. Young (1968) also mentioned the difference in the location of the genital pore in the descriptions of Tripathi (1959) and Unnithan (1962). This study confirms that the common genital pore is on the ventral side of the body. The posterior clamps on the left side have been stated as larger than the other clamps on the right side ( Unnithan 1962), but the present study has revealed that three of the four clamps on the left side are slender.

The trimmed multiple sequence alignment length of 28S rDNA and cox1 fragments consisted of 654 and 226 base pairs, respectively. Sequences of diclidophorids were used as the outgroups following Tambireddy et al. (2016). The topologies of each tree constructed by ML and BI analysis were almost identical, and the phylogenetic trees based on BI analysis are shown in Fig. 3 View Fig . These phylogenetic analyses showed that Gastrocotylinea species separated into two clades.

The clade containing the species Allodiscocotylidae , Chauhaneidae , Protomicrocotylidae , and Gastrocotylidae formed a sister group with the species Thoracocotylidae and Gotocotylidae with relatively high PP and BS values. The phylogenetic tree based on the 28S rDNA did not support the monophyly of Chauhaneidae ; Gemmaecaputia corrugata formed a sister group with a clade consisting of Allodiscocotylidae , Protomicrocotylidae , and Pseudomazocraes Caballero and Bravo Hollis, 1955 (Chauhaneidae) species. The cox1 phylogenetic tree shows that G. corrugata and Pseudochauhanea macrorchis (Chauhaneidae) formed a sister group, but this clade separated the Allodiscocotylidae species into two groups.

The past molecular phylogenetic study by Tambireddy et al. (2016) based on partial 28S rDNA sequences of the Mazocraeidea suggested that the Gotocotylidae and Thoracocotylidae are paraphyletic, and that the monophyletic Allodiscocotylidae and Protomicrocotylidae form a sister group. In the present study, the phylogeny tree based on 28S rDNA and cox1 shows that Chauhaneidae species are grouped together with Allodiscocotylidae and Protomicrocotylidae species. The results partially support the relationship of Chauhaneidae , Protomicrocotylidae , and Allodiscocotylidae estimated by phylogenetic analysis based on morphological and partial 18S and 28S rDNA sequences ( Boeger and Kritsky 1993; Camargo and Santos 2020). However, the monophyly of Chauhaneidae is not supported based on the present 28S rDNA analysis, and the cox1 tree does not support the monophyly of Allodiscocotylidae . Boeger and Kritsky (1993) indicated that the Pseudomazocraeidae is most closely related to Chauhaneidae , but no sequence of Pseudomazocraeidae species is currently available. Also, the available sequences of chauhaneid monogeneans are limited, and accumulation of molecular studies is needed for the phylogenetic analysis of these families.