Armatoplana albomaculata, Oya & Tsuyuki & Kajihara, 2022
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publication ID |
https://doi.org/ 10.11646/zootaxa.5178.5.2 |
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publication LSID |
lsid:zoobank.org:pub:2DEB6BCF-5DCA-4BBA-B548-FC586CA4719E |
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DOI |
https://doi.org/10.5281/zenodo.7039805 |
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persistent identifier |
https://treatment.plazi.org/id/3E19857F-FFD5-FF83-8AA2-5809B1D0FE26 |
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Plazi |
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scientific name |
Armatoplana albomaculata |
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sp. nov. |
Armatoplana albomaculata sp. nov.
( Figs. 2 View FIGURE 2 and 3 View FIGURE 3 )
Etymology. The new specific name albomaculata (- us, - a, - um) is a compound adjective derived from the Latin words albus and maculatus, which mean “white-spotted.” The species was named after small white spots scattered on the dorsal surface of the worms.
Diagnosis. Armatoplana without nuchal tentacles and with white spots on dorsal surface, common sperm duct, elongated oval prostatic vesicle directing posteriorly but curving dorsally in distal part, largely curved penis stylet, and small, oval Lang’s vesicle without accessory vesicles ( Figs. 2 View FIGURE 2 and 3 View FIGURE 3 ).
Material examined. Two specimens (one holotype and one paratype) ( Table 1 View TABLE 1 ).
Description. Live specimens 12–16 mm in length (16 mm in holotype), 5.9–6.6 mm in maximum width (6.6 mm in holotype). Body elongate oval, narrow toward posterior end ( Fig. 2A, B View FIGURE 2 ). Dorsal body tinged with light brown. Dorsal surface of body around pharynx pale yellow. Body margin translucent. General appearance of body yellowish translucent ( Fig. 2A View FIGURE 2 ). Small white spots scattered on dorsal surface ( Fig. 2A, C View FIGURE 2 ). Nuchal tentacles lacking. Pair of cerebro-tentacular eye clusters, each containing 44–57 eyespots (46 in right cluster, 44 in left cluster in holotype), arranged near median line ( Fig. 2C View FIGURE 2 ). Eyespots located anterior to brain widely spreading but forming clear aggregation; those located posterior to brain forming irregular aggregation with small number of eyespots. Length of anterior part of cluster clearly longer than that of posterior one. Pharynx whitish, ruffled in shape, occupying about one-fourth of body length (3.4–3.9 mm in length, 3.9 mm in holotype), located at center of body ( Fig. 2B View FIGURE 2 ). Mouth opening at slightly posterior to center of pharyngeal cavity. Intestine not anastomosed, spreading throughout body except margin. Pair of whitish sperm ducts and oviducts visible through ventral body wall ( Fig. 2B View FIGURE 2 ). Male and female gonopores separate; male gonopore opening at about two-sevenths of body length (3.3–5.2 mm, 5.2 mm in holotype) from posterior end; female gonopore situated 1.2 mm posterior to male gonopore (not observed in paratype).
Male copulatory apparatus located posterior to pharynx, consisting of seminal vesicle, interpolated prostatic vesicle, and penis stylet ( Fig. 3A, B View FIGURE 3 ). Pair of sperm ducts running anteriorly, turning medially at point about onethird to one-half length of pharynx from posterior end (one-half in holotype), subsequently running posteriorly along both sides of pharynx and extending further posteriorly for short distance beyond level of posterior end of pharynx, then turning anteriorly ( Fig. 2B View FIGURE 2 ). Distal part of sperm duct forming spermiducal vesicle and fusing to short common sperm duct. Common sperm duct also forming spermiducal vesicle in holotype, entering proximal end of seminal vesicle. Seminal vesicle elongated bean-shaped, directing antero-dorsally and having strong muscular wall ( Fig. 3C View FIGURE 3 ). Distal end of seminal vesicle connecting to prostatic vesicle. Prostatic vesicle directing posteriorly, elongated oval-shaped, and almost same size as seminal vesicle (slightly smaller than seminal vesicle in holotype), having thin muscular wall lined with smooth, thick epithelium and located dorsally above seminal vesicle ( Fig. 3B, D View FIGURE 3 ). Distal end of prostatic vesicle directing dorsally and forming penis papilla. Penis papilla armed with penis stylet directing anteriorly ( Fig. 3D, E View FIGURE 3 ). Penis stylet turning posteriorly, then curving ventrally in penis pocket ( Fig. 3A, B, D View FIGURE 3 ). About two-thirds of proximal part of penis pocket not ciliated. Distal part of penis pocket lined with ciliated epithelium and opening to male atrium ( Fig. 3B View FIGURE 3 ). Male atrium cone-shaped and lined with ciliated epithelium.
Pair of oviducts forming common oviduct, latter running postero-dorsally to enter vagina. From this point, short Lang’s-vesicle duct (about one-fifth of the length of vagina), lined with folded ciliated epithelium, running posteroventrally to connect to Lang’s vesicle ( Fig. 3F View FIGURE 3 ). Lang’s vesicle small, oval, and lined with columnar cells, lacking accessory vesicles ( Fig. 3F View FIGURE 3 ). Vagina running anteriorly, then turning posteriorly to exit at female gonopore; inner lining of about two-thirds of distal part of vagina folded. Vagina surrounded by circular muscle fibers and lined with ciliated epithelium.
Type locality. Tsujishima Island (32°33′09″N, 130°06′32″E), Amakusa, Kumamoto, Japan GoogleMaps .
Habitat. Intertidal to subtidal zones, undersurface of stones (Kumamoto) and among kelp holdfasts (Kanagawa).
Sequences of COI. The uncorrected P -distance of the partial COI sequences (712 bp) between the two specimens ( LC672054 View Materials – LC672055 View Materials ) was 0.008 .
Remarks. Armatoplana albomaculata sp. nov. resembles A. affinis ( Palombi, 1940) , A. lactoalba ( Verrill, 1900) , A. leptalea ( Marcus, 1947) , A. panamensis ( Plehn, 1896) , and A. snadda ( Du Bois-Reymond Marcus & Marcus, 1968) in that they share the following characteristics: i) nuchal tentacle absent and ii) long penis stylet present ( Table 3 View TABLE 3 ). The present species is distinguished from A. affinis by the presence or absence of the accessory vesicles in the Lang’s vesicle (absent in A. albomaculata sp. nov.; present in A. affinis ); from A. lactoalba , A. leptalea , and A. panamensis by the shape of the Lang’s vesicle (small, oval in A. albomaculata sp. nov.; large, elongated in A. lactoalba , A. leptalea , and A. panamensis ); and from A. snadda by the position of the pharynx relative to the body (located at the center in A. albomaculata sp. nov.; located anteriorly in A. snadda ) as well as the length of the pharynx relative to the body length (about one-fourth in A. albomaculata sp. nov.; about one-sixth in A. snadda ).
The white spots in A. albomaculata are remarkable. In other congeners, white spots on the dorsal surface were only described in A. taurica ( Jacubowa, 1909) ; however, the spots differ from those in A. albomaculata in that the former were represented by two different types in shape (irregular and oblong) ( Jacubowa 1909: 9). Apart from A. taurica , the presence or absence of white spots has not been explicitly mentioned in previous descriptions of other Armatoplana species; therefore, the possibility cannot be ruled out that the presence of white spots like in A. albomaculata could have simply been overlooked. If not, however, this character is useful because it allows the species to be distinguished from other congeners by external appearance alone.
This is the first report of Armatoplana from the West Pacific. Five species, namely, A. colombiana Bolaños et al., 2006 , A. divae ( Marcus, 1947) , A. lactoalba , A. leptalea , and A. snadda , were recorded from the Atlantic coast of Central and South America ( Verrill 1900; Marcus 1947; Du Bois-Reymond Marcus & Marcus 1968; Quiroga et al. 2004; Bahia et al. 2015). Two species, namely, A. panamensis and A. reishi ( Hyman, 1959) , were recorded from the Pacific coast of North and Central America ( Plehn 1896; Hyman 1953, 1959). Four species were described from Africa: A. affinis and A. vesiculata ( Palombi, 1940) from the Atlantic coast ( Palombi 1940) and A. tenuis ( Palombi, 1936) and A. robusta ( Palombi, 1928) from the coast along the Indian Ocean ( Palombi 1928, 1936). Armatoplana taurica was found in the Black Sea ( Jacubowa 1909).
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
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