Trilobodrilus ellenscrippsae, Kerbl & Vereide & Gonzalez & Rouse & Worsaae, 2018
Kerbl, Alexandra, Vereide, Emilie Hernes, Gonzalez, Brett C., Rouse, Greg W. & Worsaae, Katrine, 2018, Two new meiofaunal species of Trilobodrilus (Dinophilidae, Annelida) from California, USA, European Journal of Taxonomy 421, pp. 1-18: 12-15
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Trilobodrilus ellenscrippsae sp. nov.
Fig. 3 View Fig.3 , Tables 1, 3–7
Short Trilobodrilus with two pairs of prostomial compound cilia encircled by four pairs of intermediate ciliary tufts anterior to first ciliary band. Additional ciliary tufts between first and second ciliary band. Dorsally continuous third ciliary band. Incomplete fourth ciliary band, posterior of third ciliary band with broad dorsal gap.
This species is named (as a noun in the genitive case) to honour Ellen Browning Scripps (1836–1932), a founding benefactor of the Scripps Institution of Oceanography ( McClain 2017) in La Jolla, California.
No species have been named for her to date, yet Ellen Browning Scripps’ impact on science has been very important (see McClain 2017).
UNITED STATES OF AMERICA: complete adult, 485 µm long (platinum-palladinium-coated and mounted on stub for SEM), La Jolla Cove, La Jolla , California, 32°51′03″ N 117°16′20″ W, 9 m depth, 19 Apr. 2009, K. Worsaae and G. Rouse leg. ( SIO-BIC A8209).GoogleMaps
Additional specimens mounted on slides were unfortunately lost after conducting the measurements.
Measurements given first in the text from holotype, ranges in in parenthesis include measurements taken from the lost specimens.
Compact body, light brown tint (fixed specimens, Fig. 3A View Fig.3 ). Body length 485 µm (306–774 µm, n = 4, Tables 1, 7 View Table 7 ), width 122 µm (91–229 µm, n = 4, Tables 1, 7 View Table 7 ), body segments indistinct ( Fig. 3A–C View Fig.3 ).
Prostomial shape conical ( Fig. 3 View Fig.3 , Table 7 View Table 7 ). No eyes. Middle of the mouth located 69–88 µm (n = 4) posterior of terminal prostomium (mo, Fig. 3A, C, F View Fig.3 , Table 1). Four compound cilia terminally on prostomium (pcc, Fig. 3 View Fig.3 , Tables 1, 7 View Table 7 ), each consisting of approximately 30 cilia (n = 3); dorsal compound cilia spaced 19 µm apart (16–29 µm, n = 3), length similar to the cilia in the prostomial ciliary bands (10–18 µm long, n = 3). Prostomial compound cilia surrounded by four pairs of semicircular arranged apical ciliary tufts (act, Fig. 3B, D–E View Fig.3 , Table 7 View Table 7 ). Two prostomial ciliary bands on prostomium and one ciliary band posterior to the nuchal organs, as well as one additional incomplete fourth ciliary band posterior to these bands (cb1–4, Fig. 3B, E View Fig.3 , Table 7 View Table 7 ). First dorsally continuous ciliary band (13 µm wide, n = 1) encircles prostomium ( Fig. 3A, D–E View Fig.3 , Table 7 View Table 7 ). Several intermediate ciliary tufts located laterally between first and second ciliary band (ict, Fig. 3B, D–E View Fig.3 , Table 7 View Table 7 ). Second ciliary band (cb2, Fig. 3A–B, D–F View Fig.3 ; 24 µm wide, n = 1) dorsally incomplete with 48 µm wide gap (n = 1) and one mid-dorsal ciliary tuft in center of gap (mdt, Fig. 3B, E View Fig.3 , Table 7 View Table 7 , 40–60 cilia, n = 1).
One lateral pair of nuchal organs located between second and third ciliary band (no, Fig. 3F View Fig.3 ). Third ciliary band (10 µm wide, n = 1) dorsally continuous (cb3, Fig. 3B–E View Fig.3 , Table 7 View Table 7 ) posterior to nuchal organs. Fourth ciliary band extends laterally approx. 24 µm (n = 1) from the ventral ciliary tract (cb4, Fig. 3B, E View Fig.3 , Table 7 View Table 7 ). Ciliary tufts arranged laterally along the body (lct, Fig. 3B View Fig.3 , Table 7 View Table 7 ). Ventral ciliary tract extends from posterior prostomium to posterior pygidium (vct, Fig. 3B–C, E View Fig.3 ; width of tract relative to total body width approximately 0.44 (n = 1)). Anus opening dorso-anteriorly on pygidium.
No eggs present in the investigated specimens.
Epidermal inclusions and spindle glands in the epidermis could not be described and measured due to insufficient preservation in the investigated specimens.
The following sequences were determined by Sanger sequencing from a single, non-type specimen collected on 19 April 2009, for which no morphological voucher remains: 18S rDNA, MG588090 (1857 nucleotides (nt), Table 4); 28S rDNA, MG588092 (1126 nt, Table 5); COI, MG588094 (644 nt, Table 6); CytB, MG588096 (426 nt). In the following, the sequences of T. ellenscrippsae sp. nov. are first compared to the most similar sequences found in T. windansea sp. nov., and the range of similarities with the addition of the respective species are subsequently listed.
Trilobodrilus ellenscrippsae sp. nov. 18S rDNA is 99.9% similar to the 18S rDNA of T. windansea sp. nov., and 99.5% ( T. axi ) – 99.9% ( T. nipponicus ) similar to the other sequenced species ( Table 4). Its 28S rDNA is 99.9% similar to the 28S rDNA of T. windansea sp. nov. and 98.5% ( T. axi ) – 99.4% ( T. nipponicus ) similar to the other species ( Table 5). COI is 84.9% similar to T. windansea sp. nov., and 76% similar to the T. itoi and T. nipponicus ( Table 6). Cytochrome B resembles the sequence of T. windansea sp. nov. to 85.6%.
Subtidal in coarse to silty shell gravel at the surface layer at 9 m depth (subtidal).
Trilobodrilus ellenscrippsae sp. nov. is known from La Jolla Cove, La Jolla, San Diego, California only.
Trilobodrilus ellenscrippsae sp. nov. shows closest morphological resemblance to T. nipponicus (but nests with T. windansea sp. nov. in the molecular tree), but is much shorter, has a higher number of apical ciliary tufts on the prostomium, and its ciliary tufts along the body are not arranged in an as distinctive a pattern as in T. nipponicus ( Fig. 3 View Fig.3 , Table 7 View Table 7 ). Trilobodrilus ellenscrippsae sp. nov. resembles T. windansea sp. nov. by having apical and intermediate ciliary tufts on the prostomium, and a dorsally incomplete second ciliary band with a mid-dorsal tuft ( Fig. 3B, D–E View Fig.3 , Table 7 View Table 7 ). However, T. ellenscrippsae sp. nov. differs from T. windansea sp. nov. in the shape of the prostomium, the additional ciliary row posterior to the second ciliary band, and by having a dorsally continuous third ciliary band as well as an incomplete fourth ciliary band ( Fig. 3 View Fig.3 , Tables 1, 7 View Table 7 ).
Trilobodrilus ellenscrippsae sp. nov. further differs in its genetic sequences from all other species, see Molecular information above or Tables 4–6.
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