Tomopteris planktonis Apstein, 1900

KOLBASOVA, G. D., SYOMIN, V. L., SEMPERE-VALVERDE, J., TEIXEIRA, M. A. L. & CARVALHO, S., 2025, Holopelagic Annelida from the Red Sea off the Central Saudi Arabian coast, Zootaxa 5632 (1), pp. 1-41 : 28-29

Tomopteris planktonis Apstein, 1900

( Figs 1 , 14–15 )

Tomopteris planktonis Apstein, 1900: 42 , Pl. XI, Figs. 21, 22 [original description, Atlantic, Labrador, Guinea and South Equatorial currents].– Rosa 1908: 301 [brief description and differences from other species].– Fauvel 1923: 224, Fig. 84 d [description, North Atlantic].– Caroli 1928: 513 [brief description, Messina], 1928(1930): 18 [distribution, Red Sea], 1933: 378–379 [description, Naples].– Stǿp-Bowitz 1948: 52 [brief description, Atlantic].– Fauvel 1953: 142, Fig. 71 [description, Indian Ocean].– Dales 1957: 663 [brief description, Pacific, Cape Disappointment, Oregon, south of San Francisco Bay, Monterey Bay].– Day 1967: 206, Fig. 8.2 n –o [brief description,Atlantic Ocean from Greenland to Antarctica, North and Mediterranean seas, South Atlantic off the coast of South Africa].– Ushakov 1972: 216 [distribution, North Pacific up to 45ºN].– Orensanz & Ramirez 1973: [distribution, Brazilian, Uruguayan and Argentine shelf].– Rozbaczylo et al. 1987: 107–198, Fig. 2e [description, South Pacific, Chilean coast], 2020: 167, Fig. 9 [description and distribution, South Pacific].– Kolbasova et al. 2023: 75, Figs 25–27 [description, Antarctic Ocean, South Atlantic, Brazil-Malvinas confluence, Bransfield Strait, Orkney Through, Orkney Plateau].

Tomopteris cavallii Dales 1957: 144 , Figs. 51 b, 52 b [description, Pacific Ocean, Monterey Bay].

Material examined. Four specimens: ZMMU WS20991 , ZMMU WS20992 (FA, Et), ZMMU WS22577 , ZMMU WS22578 (Et)

Description (based on all our material). Body oval, elongate, 5–10 mm long, 0.6–1 mm wide without parapodia, 2.5–4 mm wide with parapodia. Tail absent, posterior ends with short cylindrical pygidium, maximum width with parapodia 2.6 mm, maximum width of body trunk 0.9 mm ( Fig. 15A ). Live worms transparent, white in preservation. Eyes red. Brain transversely oval ( Fig. 15B ). Body with 14 pairs of parapodia increasing in size to 3 rd pair; 4–6 pairs longest; from 7 th pair, parapodia decrease toward posterior end. Prostomium with frontal cleft, prostomial horns slightly curved backward. Ciliated epaulettes triangular, extending to posterior margin of brain. Anterior cirri absent ( Fig. 15B ). Secondary cirri (streamers) 1–1.2 of body length. Dorsal and ventral parapodial rami of equal length ( Fig. 15C–E ). Pinnules oval, pinnal membranes do not adnate to parapodial trunk, membrane in dorsal ramus slightly lower than in ventral ramus. Hyaline glands apical, from 1 st pair of parapodia in ventral pinnules ( Fig. 15C–E ). Chromophile glands from 3 rd parapodial pair, in 3 rd pair of parapodia they incompact and poorly visible, from 4 th parapodial pair chromopile glands with 8–10 tubes, compact and large; base of ventral ramus terminates at proximal end of chromophile gland and not bordered by pinnule ( Fig. 15C–E ). Small yellow rosettes present from 1 st pair of parapodia, they are located in ventral pinnule between chromophile and hyaline glands ( Fig. 15C–E ). Gonads in dorsal rami ( Fig. 15E ).

Distribution. Type locality: Labrador, Guinea, South Equatorial currents ( Apstein 1900). Later records for T. planctonis include: Atlantic Ocean from Greenland to Antarctica, Mediterranean, Pacific; Central Red Sea (this study).

Remarks. Both morphologically and according to 18S and 28S markers, T. planktonis from the Red Sea is similar to T. planktonis from the Weddell Sea.

Applicability of the COI marker obtained with universal primers in holopelagic annelid families

General topology of the tree inferred from nuclear 18S and 28S including all considered families is presented in Fig. 16A . It conforms to contemporary conception of relationships between holopelagic annelid families. However, including COI sequences in the analysis introduces some changes in the topology above genus level, although it does not affect the species-level results. Thus, in 18S + 28S + COI concatenated tree within the family Typhloscolecidae , the genus Typhloscolex becomes non-monophyletic with one lineage merged inside Travisiopsis ( Fig. 16B ). Tomopteridae are grouped with Glyceridae in the 28S + 18S tree ( Fig. 16A ). Conversely, when the COI is added to the analysis, the Tomopteridae clade becomes a sister group to Typhloscolecidae ( Fig. 16B ). Nothing changes only in Alciopini , which are nested within Phyllodocidae regardless of which set of markers was used ( Fig. 16 ).

Figures

FIGURE 1. Location of the study area and sampling scheme. Designations: yellow, green and purple circles mark first (12.12.2023), second (18.12.2023) and third (17.04.2024) sampling events, respectively.

FIGURE 2. Krohnia cf. lepidota ZMMU WS20944, general view. (A) anterior end, dorsal view, (B) anterior end, ventral view. Designations: fan–frontal antennae, man–median antenna, dc–regular dorsal tentacular cirri (pairs D1 and D2), ecs–cirrostyle of enlarged dorsal tentacular cirrus (pair D3), ecp–cirrophore of enlarged dorsal tentacular cirrus (pair D3), vc–ventral tentacular cirri, dcp–cirrophore of dorsal parapodial cirrus, vpc–ventral parapodial cirrus. Small black arrowheads point at brown dots, big white arrowheads point at segmental glands. A and B to same scale.

FIGURE 8. Plotohelmis cf. capitata ZMMU WS20963, parapodia. (A) segment 5, (B) segment 8, (C) segment 12, (D) segment 20. Designations: small black arrows point at broken acicular chaetae. A–C to same scale.

FIGURE 9. Relationships of Pelagobia longicirrata from the Red Sea (ZMMU WS20993) with other Pelagobia species (data from GenBank) using the 18S gene marker. Black numbers above branches indicate Maximum Likelihood (ML) bootstrap values; blue numbers below show Bayesian posterior probabilities (BI). ID of the specimen collected in the Red Sea during the present study marked with blue box.

FIGURE 14. Relationships of Tomopteris planktonis (ZMMU WS20991, WS22577 and WS22578) and Tomopteris rolasi (ZMMU WS20992) from the Red Sea with some other Tomopteridae. Maximum Likelihood tree inferred from concatenated 18S and 28S sequences obtained from our material and from GenBank. Black numbers above branches indicate Maximum Likelihood (ML) bootstrap values; blue numbers below show Bayesian posterior probabilities (BI). IDs of specimens collected in the Red Sea during the present study marked with blue boxes.

FIGURE 15. Tomopteris planktonis ZMMU WS20991, ZMMU WS20992 (A) general view, (B) anterior end, (C) 1st –2nd parapodia, (D) 3rd parapodium, (E) 4th parapodium. Designations: br—brain, ce—ciliated epaulette, ch—chromophile gland, go–gonad, hy—hyaline glands, mo—mouth, rs—rosette, st—streamer (secondary cirrus), ph–pharynx, pr—prostomium.

FIGURE 16. Bayesian tree inferred from concatenated alignments including all 18S and 28S sequences (A), and 18S + 28S + COI sequences (B) together with corresponding sequences from GenBank. Black numbers above branches indicate Maximum Likelihood (ML) bootstrap values; blue numbers below show Bayesian posterior probabilities (BI). Numbers in brackets indicate number of individual vouchers in a collapsed branch. IDs of specimens collected in the Red Sea during the present study marked by blue filling with yellow text.