Ceratodoris trypomandyas Paz-Sedano & Cobb & Gosliner & Pola 2024, sp. nov.
Creators: name: Paz-Sedano, Sofia
name: Cobb, Gary
name: Gosliner, Terrence M.
name: Pola, Marta
Publisher: name: Zenodo
Year: 2024
Subjects: Biodiversity
Taxonomy
Animalia
Mollusca
Gastropoda
Nudibranchia
Goniodorididae
Ceratodoris
Ceratodoris trypomandyas

description: Ceratodoris trypomandyas sp. nov.
(Figs. 1F‒G, 2I‒J, 5A‒D)
Zoobank: urn:lsid:zoobank.org:act: DF05B4F3-E63D-4755-B974-97FE32B7A077
Okenia plana — Rudman (2004): 49; Figs. 20C, 23, 24B, 27D, 29F, 30A.
Okenia plana — Debelius & Kuiter (2007): 24.
Ceratodoris spD — Paz-Sedano et al. (2024).
Type material. Holotype. QM MO 86033, La Balsa Park, Mooloolah River, Queensland, Australia, 0.5–3 m depth, 03 November 2020, col. by G. Cobb, 96% EtOH; Paratypes. QM MO 86034, La Balsa Park, Mooloolah River, Queensland, Australia, 0.5–3 m depth, 03 November 2020, col. by G. Cobb, 96% EtOH, dissected (SEM: radula, labial cuticle); AM C270711, La Balsa Park, Mooloolah River, Queensland, Australia, 0.5–3 m depth, 03 November 2020, col. by G. Cobb, 96% EtOH; AM C270712, La Balsa Park, Mooloolah River, Queensland, Australia, 0.5–3 m depth, 03 November 2020, col. by G. Cobb, 96% EtOH, dissected (SEM: radula, labial cuticle).
External morphology (Figs. 1F‒G). Preserved specimens 2–4 mm in length, live 3–5 mm. Body rounded and very flat, with developed notal border. Dorsal part of body bearing thin, relatively small, and elongated papillae. Five papillae border each side of dorsum. One in front of rhinophores, three between rhinophores and gill, and one behind gill. One additional papilla located in middorsal part of body. All papillae have same shape and size. Rhinophores nonretractile, elongated, slender, bearing 9–12 lamellae each oriented to posterior part. Rhinophoral sheaths absent. Gill composed of nine small, plumose branches forming a semicircle around anus. One middorsal branch larger, four smaller branches on each side. Posteriormost gill branches tiny. One oral tentacle on each side of mouth, semicircular, almost fused with body. Reproductive opening located on right lateral side, in first third of body. Mantle covered by very dense network of spicules, forming a rhomboid pattern.
Color pattern (Figs. 1F‒G). Background of body translucent. Light brown patches covering body, delimited with a network of hyaline white lines. Rhinophores same color as body. Papillae translucent, may have some brown patches. Gill branches translucent. A dense network of spicules visible, providing a bright tone.
Foregut anatomy (Figs. 2I, 5A‒D). Buccal bulb thick, muscular (Fig. 2I). Large and elongated buccal pump located dorsally and expands posteriorly. Rounded radular sac located ventrally. Esophagus begins behind buccal pump. Very small, oval salivary glands located at junction of esophagus with buccal bulb. Nervous system surrounds this junction, covering salivary glands. Esophagus continues posteriorly and inserts into digestive-hermaphroditic gland. Thin, weak labial cuticle surrounds lips and expands within buccal pump. Labial cuticle with honey-comb elements (Fig. 5A). Radular formula 23‒24 × 1.1.0.1.1. Inner lateral tooth large, with single cusp, and wide rectangular base (Figs. 5B–C). Cusp large and pointed with smooth masticatory margin (Fig. 5B–C). Base ends in somewhat prominent wing, with rounded external edge. Outer lateral tooth much smaller (Figs. 5B–C). Base of outer tooth rectangular, top with large and pointed cusps. Cusps located externally larger than inner cusps, form a circle where inner cusps remain inside (Figs. 5B–D). Outer teeth may have four to six cusps. External cusps larger than inner ones (Fig. 5D).
Reproductive system (Fig. 2J). Reproductive system located in anterior third of body. Thin hermaphroditic duct begins at ovotestis, located inside digestive-hermaphroditic gland. Hermaphroditic duct expands into small, kidney shape ampulla. On opposite side of hermaphroditic duct, a postampullary duct emerges and joins prostate. Oviduct connects near union of postampullary duct with prostate. Short, oviduct enters inside female gland mass. Prostate very large, wide, and elongate, continues as thin and long vas deferens. Vas deferens expands to short ejaculatory duct. Penial spines were not appreciated. Vagina thin, half width than vas deferens, very long. Vagina connects with large, rounded bursa copulatrix. From bursa copulatrix arises a short and thin duct that connects with tiny, oval receptaculum seminis. At base of receptaculum seminis arises a thin and long uterine duct. Vagina and receptaculum seminis completely attached, resembling a single duct before separation during dissection.
Etymology. The name “trypomandyas ” has Greek origin. Trypo means holes and mandyas mantle, referring to the light brown patches that resemble holes on the body.
Distribution. Australia (Rudman 2004; Debelius & Kuiter 2007; present study) and China (Rudman 2004).
Natural history. Rudman (2004) found specimens on brown algae and on different species of bryozoans, including Jellyella tuberculata (Bosc, 1802), Cryptosula pallasiana (Moll, 1803). The author documented one specimen preying on Membranipora membranacea (Linnaeus, 1767).
Remarks. Within the genus Ceratodoris, C. plana (Baba, 1960) and C. pilosa (Bouchet & Ortea, 1983) share with C. trypomandyas sp. nov. a flattened body bearing dorsal thin papillae, with brownish speckles on translucent whitish background. Ceratodoris eolida (Quoy & Gaimard, 1832) has a similar body shape but it has white body and few red patches (Quoy & Gaimard 1832). Ceratodoris plana and C. pilosa differ by having five pairs of papillae and several dozen papillae, respectively (Bouchet & Ortea 1983). Moreover, C. plana has one papilla in the central part of the body while C. pilosa has five (Bouchet & Ortea 1983). The new species C. trypomandyas sp. nov. resembles C. plana, having five pairs of papillae and one additional middorsal papilla.
After its original description, C. plana was redescribed by Gosliner (2004) using specimens from California (USA) and the Philippines, and by Rudman (2004) using specimens from Australia and China. Both authors described the species having five pairs of papillae and a single middorsal one. However, the color pattern of the specimens of each author did not completely match. Gosliner (2004) described the species as “translucent yellowish white with the exception of small brown spots scattered over the surface of the notum and occasional opaque white spots”. Rudman (2004) described a variation of color, depending on the locality. Specimens from Australia were described as “translucent white with closely packed, relatively large, brown patches, […] each brown patch is edged with a thin opaque white line. Sometimes the opaque white pigment is absent.” Specimens from Hong Kong were described having small dark brown spots instead large brown patches. In addition to these subtle variations in the color pattern, the anatomy of the reproductive system of the specimens used by Gosliner (2004) and Rudman (2004) also disagreed. The receptaculum seminis joins at the base of the bursa copulatrix, together with a long uterine duct in Rudman’s specimens. In Gosliner’s specimens, an elongate and narrow duct arises from the base of the bursa copulatrix and connects with a pyriform receptaculum seminis.
These differences in external and internal anatomy support the possibility that several different species have been described under the name of C. plana due to their external similarity. The existence of several similar species of Ceratodoris is also supported by molecular analyses (Paz-Sedano et al. 2024). In the original description, Baba (1960) described C. plana as having a plentifully sprinkled with minute spots of chocolate brown on the translucent whitish ground, which is most consistent with Gosliner´s (2004) description. Moreover, C. plana was described having yellow rhinophores, and the tips of the papillae densely whitish. Ceratodoris trypomandyas sp. nov. lacks yellow color and the papillae have brownish patches. Baba (1960) did not give details of the reproductive system. Rudman´s (2004) description matches the new species C. trypomandyas sp. nov., who also studied specimens from Australia.
description: Published as part of Paz-Sedano, Sofia, Cobb, Gary, Gosliner, Terrence M. & Pola, Marta, 2024, Filling gaps in the knowledge of Goniodorididae taxa (Mollusca, Gastropoda, Nudibranchia) with description of seven new species, pp. 523-547 in Zootaxa 5443 (4) on pages 533-535, DOI: 10.11646/zootaxa.5443.4.3, http://zenodo.org/record/11064312