Dendronotus dalli Bergh, 1879

User, GBIF. Org, 2021, A synoptic review of the family Dendronotidae (Mollusca: Nudibranchia): a multilevel organismal diversity approach, Contributions to Zoology 90 (1), pp. 93-153 : 115-122

publication ID	https://doi.org/ 10.1163/18759866-BJA10014
persistent identifier	https://treatment.plazi.org/id/1E1A4C68-FF92-FFE3-51C9-FD8FFE76D821
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scientific name	Dendronotus dalli Bergh, 1879
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Dendronotus dalli Bergh, 1879 View in CoL Distribution. North Pacific (The Sea of Japan

Fig. 7 View FIGURE 7 in the west and at least Washington State, USA Dendronotus dalli Bergh, 1879: 94 , Pl. 1, Fig. in the east to at least Chuckchii Sea; Russia, in 21; Pl. 2, Figs 9–12; Pl. 3, Figs 2–6 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 ; Robilliard, the Arctic (may possibly penetrate further to 1970: 452–455, Figs 13–15; McDonald, 2009: the west in the Arctic).

463 (bibliography); Martynov & Korshunova,

2011: 155–157 (verified photographs of living Bathymetry. Verified records from 5 to 50 m specimens, description and biology in NW depth.

Pacific); Ekimova et al., 2015: 860–863, Figs 6C View FIGURE 6 ,

8G View FIGURE 8 , 11, 12, 13A. Remarks. Until recently, the North Atlantic D. Dendronotus frondosus var. dalli Bergh , elegans (see below) has been confused with 1879 – Odhner, 1907: 19. the North Pacific D. dalli . The best external Not D.dalli sensu Bergh, 1886 , Knipowitsch, feature to distinguish these two closely 1902, Roginskaya, 1987 (= D. elegans Verril , related species is the presence of an external 1880). opaque white pigment on the apical parts of the dorsolateral processes in D. dalli , whereas Extended diagnosis. Body relatively narrow. in D. elegans such a pigment, if present, is Four to eight pairs of branched dorsolateral internal. These species may co-occur in some appendages. Four to five appendages of oral Arctic localities, but this needs to be further veil. Four to 12 appendages (equal in size or investigated. For D.dalli an absence of tertiary few posterior ones longer) of rhinophoral branches of the dorsolateral appendages stalks. Lateral papilla of rhinophoral sheaths was incorrectly mentioned by Ekimova et al. present. Rhinophores with 16–33 lamellae. (2015).There is a possibility that light-coloured Lip papillae 15–40 (and more). Basal colour varieties of D. kamchaticus were depicted uniform translucent gray, light yellow to under D.dalli , judging from photographs in for orange, brownish or pinkish, with external example Behrens (1980) (see also Korshunova opaque white pigment on tips of dorsolateral et al., 2016a). In some studies, Dendronotus appendages. Dorsal processes of jaws inclined dalli was incorrectly considered a synonym of posteriorly at approximately 60° to the D. frondosus (Odhner, 1936; MacFarland, 1966) longitudinal axis of the jaw body and0.45 of its due to an underestimation of the importance length. Masticatory processes apparently bear of ontogenetic Downloaded radula from data Brill.com (central 12/12/2023 teeth 04:12 are:08PM via Open Access. This is an open access article distributed under the terms of the CC BY 4.0 License. https://creativecommons.org/licenses/by/4.0/

denticulated in juveniles and usually smooth the jaw body and 0.43of its length.Masticatory in adults). processes apparently bear denticles (which We have investigated a considerable num- may possess ridge-like structures). Radula ber of specimens and sequences of D. elegans with up to 42 rows of teeth. Central tooth from the North Atlantic and neighbouring completely smooth in adults. Up to at least subarctic regions. There are no confirmed 13 lateral teeth with up to eight denticles records of true D. dalli in the North Atlantic (can be more). Bursa copulatrix large, oval. and neighbouring regions. The indication of Seminal receptaculum small placed distally at D. dalli from the North Atlantic (Genbank a moderately short distance from the vaginal COI AF249800) in a table of the paper of opening. Prostate discoid with up to 60 and Wollscheid-Lengeling et al. (2001) is due to a more alveolar glands (their number was mix-up of localities, in this case with the North considerably underestimated in the original Pacific. The same can be said about Cadlina description of its new synonym D. niveus (see luteomarginata from the North Atlantic in remarks below). The vas deferens is moderate the same paper (Wollscheid-Lengeling et al., in length, penis strong, conical. Body length 2001) for which Johnson (2010: 142) explained up to 70 mm. that they originated from the North Pacific.

Distribution. North Atlantic (known southern Dendronotus elegans Verrill, 1880 limit – Cape Cod, USA) to the Arctic

Figs 7 View FIGURE 7 , 8 View FIGURE 8 (including Barents Sea and White Sea, known Dendronotus elegans Verrill, 1880: 385–386 . northeastern limit is the Laptev Sea, Russia). Dendronotus “elongatus”: Roginskaya, 1987: 175 (lapsus calami for D. elegans Verrill, 1880 ). Bathymetry. 10–25 m (White Sea) to 258 m Dendronotus niveus Ekimova, Korshunova , depth (western North Atlantic). Shepetov, Neretina, Sanamyan & Martynov, 2015: 864–869 , Figs 6D View FIGURE 6 , 8F View FIGURE 8 , 13B, 14, 15 syn. nov.; Remarks. Ekimova et al. (2015) overlooked Valdés et al., 2017: 6–7, 4B, 5B. important details in the original description Dendronotus dalli sensu Bergh, 1886 (non of D. elegans Verrill, 1880 , for which a big Bergh, 1879); Robilliard, 1970: 452; Bleakney, animal with uniform salmon-coloured body 1996: 109 ( D. elegans incorrectly mentioned as was used, and a special mentioning was synonym of D. dalli ). made of the completely smooth central teeth

(Verrill, 1880: 385–386). These characters are Extended diagnosis. Body relatively narrow. identical to those of the recently described Five to ten pairs of branched dorsolateral D. niveus Ekimova et al., 2015 . The available appendages. Six to nine appendages of oral molecular data (Valdés et al., 2017; present veil. Four to five appendages (equal in size study, figs 1–3) also show that specimens or few posterior ones longer) of rhinophoral identified as D. niveus from off the east coast stalks. Lateral papilla of rhinophoral sheaths of North America (relatively close to the present. Rhinophores with 8–23 lamellae. Lip type locality of D. elegans ) are identical to papillae 8–50. Basal colour uniform, pinkish specimens from the type locality of D. niveus to light orange, with internal opaque white in the White Sea. The holotype of D. elegans pigment of tips of dorsolateral appendages. in the Smithsonian Institution (NMNH, 2020) Dorsal processes of jaws inclined posteriorly at is not suitable for molecular study. However, approximately 40° to the longitudinal axis of a microslide Downloaded with radula from of Brill.com the holotype 12/12/2023 is 04:12:08PM

via Open Access. This is an open access article distributed under the terms of the CC BY 4.0 License.

https://creativecommons.org/licenses/by/4.0/ kept separately in the Yale Peabody Museum generally be described as highly branched,

of Natural History (YPM IZ 010761.GP) and giving this species a fluffy appearance. Eight to available as online images (Yale Peabody 15appendages of oral veil.Five to six appendages Museum, 2020), which confirm the presence (posterior one very long) of rhinophoral stalks.

of massive smooth central teeth. The date Lateral papilla of rhinophoral sheaths present.

(6September1879), the depth (26fathoms =48 Rhinophores with 11–17 lamellae. Lip papillae meters) and locations (Stellwagen Bank, off 20–49.Basalcolourreddish-brownwithopaque Cape Cod) for collecting data of the holotype white stripes between dorsolateral processes to of D. elegans exactly match radula YPM IZ uniform light yellow with small brown spots .

010761.GP, the preserved body USNM 842116 Dorsal processes of jaws inclined posteriorly and the original description of D. elegans at approximately 60° to the longitudinal in Verrill (1880). Additional morphological axis of the jaw body and 0.43 of its length.

information of the molecularly investigated Masticatory processes apparently with fine specimens of D. elegans of the present study denticles. Radula with up to 37 rows of teeth.

is given in fig. 8. It is evident that specimens Central tooth with up to 20 small denticles from the Atlantic North American coast without furrows, rarely completely smooth.

and from the Arctic Eurasian regions are Up to 11 (usually 9–10) lateral teeth with up morphologically similar according to their to seven denticles. Ampulla with at least two external and internal features. We therefore loops. Bursa copulatrix large, rounded. Seminal synonymize Dendronotus niveus Ekimova et receptaculum small placed distally at a short al., 2015 with D. elegans Verrill, 1880 . Another distance from the vaginal opening. Prostate species with smooth central teeth at the discoid with a range of 35–40 alveolar glands.

adult stage is D. dalli Bergh, 1879 (see above, The vas deferens is very long, penis relatively figs 1, 2), but this one is found predominantly narrow, bent. Body length up to 100 mm.

in the North Pacific and differs from D.

elegans in habitus morphology (apical parts Distribution. NE Atlantic, so far known from of dorsolateral appendages with external the Netherlands, Norway, Sweden and the UK.

opaque white pigment vs. with internal or absent white pigment in D. elegans ) and Bathymetry. 15–150 m depth.

molecular data.

Remarks. This species has been separated Dendronotus europaeus Korshunova , from from D. frondosus and D. lacteus based on

Martynov, Bakken & Picton, 2017 both morphological and molecular evidence

Fig. 7 View FIGURE 7 (Korshunova et al., 2017b).

Dendronotus europaeus Korshunova ,

Martynov, Bakken, Picton, 2017: 1–8, Figs. 1–2 View FIGURE 1 View FIGURE 2 ; Dendronotus frondosus (Ascanius, 1774) Supplementary information, text and figure. Fig. 7 View FIGURE 7

Dendronotus frondosus sensu Thompson Amphitrite frondosa Ascanius, 1774: 155–158 ,

and Brown, 1984 (partim.); not Ascanius, 1774. Pl. 5, Fig. 2 View FIGURE 2 (neotype selected in Ekimova et al.

2015).

Extended diagnosis. Body relatively narrow. Dendronotus frondosus (Ascanius, 1774) –

Six to nine pairs of branched dorsolateral Odhner, 1936: 1105–1109, Fig. 39 (mixture of appendages, including two to three posterior several species); Robilliard, 1970: 441–446, ones. The dorsolateral appendages can Pl. 63, Fig. Downloaded 29, text and from Figs Brill.com 4, 7, 8 12,/9 12/ (2023 partim04:12,:08PM via Open Access. This is an open access article distributed under the terms of the CC BY 4.0 License. https://creativecommons.org/licenses/by/4.0/ mostly referred to D. venustus ); Ekimova et al. eight) lateral teeth with up to seven denticles.

2015: 848–857, Figs 1–5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 , 6A View FIGURE 6 , 7A View FIGURE 7 , 8A View FIGURE 8 . Ampulla voluminous, folded. Bursa copulatrix Doris arborescens Müller, 1776:229 (mixture large, oval to rounded. Seminal receptaculum of several species). small placed distally at a moderately short Doris cervina Gmelin, 1791: 3105 , no. 12. distance from the vaginal opening. Prostate Tritonia reynoldsii Couthouy, 1838: 74–80 , discoid with range 16–30 alveolar glands.

Pl. 2, Figs 1 View FIGURE 1 , 2 View FIGURE 2 , 3 View FIGURE 3 , 4 View FIGURE 4 . The vas deferens is moderate in length, penis Tritonia felina Alder & Hancock, 1842: 33 . relatively long, curved. Common body length

Tritonia pulchella Alder & Hancock, 1842 : no more than 50 mm.

33–34.

Tritonia ascanii MØller, 1842: 5. Distribution. North Atlantic, both east and Amphitridea fabricii Kröyer, 1847: 114. west parts, not distributed to the Arctic Campaspe pusilla Bergh, 1863: 471–478 , Pl. further than the easternmost border of the 12, Figs 28–35. Barents Sea.

Campaspe major Bergh, 1886: 21–24 View in CoL ; Pl. 1,

Figs. 23–26; Pl. 2, Figs 1 View FIGURE 1 –11. Bathymetry. Intertidal to 20–30 m depth.

Dendronotus luteolus Lafont, 1871: 267 View in CoL .

Dendronotus junior Mörch, 1875: 125 . Remarks. Three common North Atlantic Dendronotus arborescens var. aurantiaca View in CoL shallow water species, namely D. europaeus Friele, 1879: 284 View in CoL . Korshunova et al., 2017b, D. frondosus NB View in CoL : Mixture of several species under the (Ascanius, 1774), and D. lacteus View in CoL , show an name Dendronotus frondosus View in CoL in the literature extremely similar range of habitus variation before 2015. (see Korshunova et al., 2017b) and have been confused in older literature. Therefore, the Extended diagnosis. Body narrow. Five to six verified distribution of D. frondosus View in CoL can only pairs of branched dorsolateral appendages. be assessed using recent data (Korshunova Four to seven appendages of oral veil. Four to et al., 2017b) that covers at least the North East five appendages (middle and posterior ones Atlantic from Norway and also the Barents can be longer) of rhinophoral stalks. Lateral Sea and the White Sea to possibly France / papilla of rhinophoral sheaths present. northern Spain. The range of D. frondosus Rhinophores View in CoL with six to 12 lamellae. Lip does not extend further than the the true papillae four to 12. Basal colour brownish to Arctic. Also, several deep-water records of reddish-brown, often with small white and D. frondosus View in CoL (e.g., Odhner, 1939; Swennen, yellow specks, but usually without opaque 1961; Thompson & Brown, 1984) most likely white stripes between dorsolateral processes refer to D. lacteus View in CoL , since according to our data to completely white translucent specimens. D. frondosus View in CoL was usually found shallower Dorsal processes of jaws inclined posteriorly than 20–30 m depth. We have examined an at approximately 60° to the longitudinal extensive collection of various Dendronotus View in CoL axis of the jaw body and 0.4 of its length. from the NW Pacific and NE Pacific and Masticatory processes apparently bear ridge- have so far not found any specimen from the like structures and denticles. Radula with up North Pacific for which the identity could to 42 rows of teeth. Central tooth with deep be confirmed as D. frondosus View in CoL despite the furrows and with up to 14 (common range presence of a few published records (e.g., 8–12) distinct denticles. Up to 10 (usually up to Ekimova Downloaded et al., 2016 from Brill). In.com this12/12 respect /2023 04,:12 the:08PM via Open Access. This is an open access article distributed under the terms of the CC BY 4.0 License. https://creativecommons.org/licenses/by/4.0/ common occurrence of true D. frondosus View in CoL in 1–3) with stable distinct differences in exter-

the North Atlantic and the extreme rarity nal and internal morphology (fig. 4) and of D. frondosus in the North Pacific, with without any gene flow between each other.

the simultaneous common presence in Dendronotus kalikal thus does not occur the North Pacific of other species formerly naturally in the North Atlantic. A potential considered as “ D. frondosus ”, (e.g., D. kalikal , future introduction of some North Pacific D. kamchaticus , D. primorjensis , D. venustus ), species from the “ D. frondosus megacomclearly suggests that true D. frondosus does plex” may take place, but so far there are not occur naturally in the North Pacific. no reliable records of any North Pacific spe- Here, it is largely substituted by other species cies in the North Atlantic. At least recently,

from the D. frondosus species complex. In a case of evident anthropogenic transporparticularly, D. primorjensis endemic to the tation of the dendronotid Pseudobornella

Sea of Japan, is morphologically similar to orientalis was reported from Japan or China D. frondosus and sister to it according to our to NE Pacific (Agarwal et al., 2017) (for taxmolecular phylogenetic analysis (fig. 1). D. onomy of Pseudobornella see below). Thus, primorjensis has several traceable diagnostic most previous records of this species from features in radula and reproductive system the Northwest Pacific refer to one of three

(see Korshunova 2016a and Synopsis below). recently described species, D. kamchaticus

By such features and molecular data D. Ekimova et al., 2015, D. kalikal Ekimova et primorjensis could be excellent candidate al., 2015, or D. primorjensis Martynov et al. ,

for an example of a relict species, with 2015, and in the Northeast Pacific, previous close relatives with ranges extending to the records refer to D. venustus Stout et al., 2010 Arctic , which afterwards formed a separate or D. kamchaticus Ekimova et al., 2015 (see species, D. frondosus , in the North Atlantic. also Korshunova et al., 2016a, b).

As a result of such an evolutionary history, D.

primorjensis and D. frondosus are evidently Dendronotus gracilis Baba, 1949

naturally separated from from closely related Dendronotus gracilis Baba, 1949: 167 , Pl. 35, North Pacific and North Atlantic species, Fig. 127, text-fig. 109; Robilliard, 1970: 461–462; because true D. frondosus does not occur in Nakano, 2018: 385.

the Arctic. On the contrary, the potentially disrupted populations of D. frondosus in Diagnosis (original description). Body the North Atlantic and the North Pacific do narrow. Four pairs of branched dorsolateral not reveal morphological and molecular appendages. Four veil appendages. Five to differences. Most reliable explanations for six processeses of the rhinophoral stalks.

such an occurrence of few of so far known Rhinophores with 18 lamellae. Basal colour specimens of D. frondosus in the North bluish-white, with numerous scattered Pacific can be an anthropogenic introduction yellow spots, various processes opaque white.

or a mistake in the sorting or processing of Masticatory processes of jaws with denticles.

collection material. Dendronotus frondosus Radula with up to 41 rows of teeth. Central does not occur naturally in the North Pacific. tooth with up to 20 small denticles without

In this study we also evidently show that furrows, rarely completely smooth. Up to the North Pacific D. kalikal and the North eight lateral teeth with up to nine denticles.

Atlantic and Arctic D. yrjargul sp. nov. are Reproductive system unknown. Body length invariably placed in two distinct clades (figs 25 mm (living Downloaded, original from description Brill.com 12) /. 12/2023 04:12:08PM via Open Access. This is an open access article distributed under the terms of the CC BY 4.0 License. https://creativecommons.org/licenses/by/4.0/ Distribution. Japan, Pacific side of Honshu, Japan.

transportation, which is hard to explain in this case and needs verification.

Bathymetry. 160 m depth(original description). Dendronotus iris Cooper, 1863

Fig. 7 View FIGURE 7

Remarks. This species is insufficiently known. Dendronotus iris Cooper, 1863: 59 ; Information on the internal morphology of MacFarland, 1966: 257–265, Pl. 47, Figs 12– specimens from the type locality is restricted 18; Plate 48, Figs 1–6 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 View FIGURE 6 ; Pl. 49, Fig. 4 View FIGURE 4 ; Pl. 50, Fig.

to the original description (Baba, 1949). 1; Pl. 51, Figs 1–5 View FIGURE 1 View FIGURE 2 View FIGURE 3 View FIGURE 4 View FIGURE 5 ; Robilliard, 1970: 446–450, Additional data in Pola and Stout (2008) Figs 4–6 View FIGURE 4 View FIGURE 5 View FIGURE 6 , 10–12, Pl. 63, Fig. 30; Behrens, 1980: referring to D. gracilis specimens are from 74; Behrens & Hermosillo, 2005: 94.

considerably remote locations off the tropical Dendronotus giganteus O’Donoghue, 1921 : island of Okinawa, whereas the type locality 187–190; Pl. 4, Fig. 47; Pl. 5, Figs 57–59 .

of D. gracilis is in the temperate Sagami Bay.

Their study lacks molecular data and may Extended diagnosis. Body relatively represent a separate species. The Okinawan narrow. Four to eight pairs of branched specimen indicated in Pola and Stout (2008) dorsolateral appendages. Two to four oral has eight pairs of dorsolateral processes, six veil appendages. Two to five appendages processess of the oral veil, and 12 rhinophoral (longest internal) of rhinophoral stalks.

lamellae, whereas according to the original Lateral papilla of rhinophoral sheaths description in Baba (1949) there are four pairs present. Rhinophores with 15–31 lamellae.

of dorsolateral processes, four processesses 20–40 lip papillae. Basal colour grayish to of the oral veil, and 18 rhinophoral lamellae, reddish-orange, with white line bordered respectively. Taking into consideration that foot edge. Dorsal processes of jaws inclined details of colour patterms between the original posteriorly at approximately 40° to the description of D. gracilis and Okinawan longitudinal axis of the jaw body and 0. 35 specimens are also different as indicated by of its length. Masticatory processes bear Pola and Stout (2008: 65), we cannot confirm denticles (possibly including ridge-like the conspecificity of the Okinawan specimens structures and denticles). Radula with up with the original D.gracilis , even if we consider to 61 rows of teeth. Central tooth quite the potentially cooler waters in Okinawa at 69 narrow, with deep furrows and with up to

m depth and that only a few specimens were 18 distinct denticles. Up to 21 lateral teeth involved in the comparison. Furthermore, Pola commonly smooth, occasionally with up to and Stout (2008) considered specimens from eight denticles. Ampulla relatively narrow New Zealand as belonging to D. gracilis as well, with numerous loops. Bursa copulatrix which also show differences in colouration. moderate in size, oval, bent. Seminal However, in the light of a modern emerging receptaculum small, placed distally at a paradigm of multilevel organismal diversity moderately short distance from the vaginal that challenges the previously concept of opening. Prostate very long, non-discoid, widely claimed polytypic species with broad linear, with numerous alveolar glands. The ranges in favour of considerably smaller, often vas deferens is short, penis moderately geographically restricted species, a potential short, straight, with blunt tip. Body length presence of true D. gracilis in New Zealand of live specimens may reach more than can only be the result of an anthropogenic 20 cm. Downloaded from Brill.com 12/12/2023 04:12:08PM via Open Access. This is an open access article distributed under the terms of the CC BY 4.0 License. https://creativecommons.org/licenses/by/4.0/ Distribution. NE Pacific, from southern Alaska to California (but records from Baja California need to be confirmed). As an adult it feeds on cerianthid anthozoans (Wobber, 1970; Shaw, 1991), quite different to other Dendronotus species.

Bathymetry. 10–30 m depth.

Remarks. This species is clearly distinguished by a combination of external characters (uniform grayish to reddish-orange colour, massive dorsal appendages) and internal characters (linear instead of discoid prostate – unique for the genus), and also by adult behavioral patterns (special “rearing attack” feeding on species of Ceriantharia, e.g., Shaw, 1991). Dendronotus nanus Marcus et Marcus, 1967 was considered a synonym of D. iris (Stout et al., 2010) , but in the absence of molecular data and presence of morphological differences (see below) we prefer to retain D. nanus as a separate species (see details below). Dendronotus iris possibly is the largest species of its genus.