Small RNA class transition from siRNA/piRNA to miRNA during pre-implantation mouse development

Recent studies showed that small interfering RNAs (siRNAs) and Piwi-interacting RNA (piRNA) in mammalian germ cells play important roles in retrotransposon silencing and gametogenesis. However, subsequent contribution of those small RNAs to early mammalian development remains poorly understood. We investigated the expression profiles of small RNAs in mouse metaphase II oocytes, 8–16-cell stage embryos, blastocysts and the pluripotent inner cell mass (ICM) using high-throughput pyrosequencing. Here, we show that during pre-implantation development a major small RNA class changes from retrotransposon-derived small RNAs containing siRNAs and piRNAs to zygotically synthesized microRNAs (miRNAs). Some siRNAs and piRNAs are transiently upregulated and directed against specific retrotransposon classes. We also identified miRNAs expression profiles characteristic of the ICM and trophectoderm (TE) cells. Taken together, our current study reveals a major reprogramming of functional small RNAs during early mouse development from oocyte to blastocyst

Tellervotrema katadara (Kuramochi, 2001) Kuramochi 2009

<i>Tellervotrema katadara</i> (Kuramochi, 2001) Kuramochi, 2009 <p>(Figs. 1–3)</p> <p> <b>Synonym.</b> <i>Plagioporus katadara</i> Kuramochi, 2001</p> <p> <b>Type-host.</b> <i>Gadomus colletti</i> Jordan & Gilbert; Gadiformes: Macrouridae: Bathygadinae.</p> <p> <b>Type-locality.</b> Tosa Bay, off the Pacific coast of southern Japan, 33°11.09’N, 133°40.11’E – 33°11.91’N, 133°40.99’E, depth = 518–522 m, 25/June/2000.</p> <p> <b>Other locality.</b> Tosa Bay, off the Pacific coast of southern Japan, 33°08.517’N, 133°38.557’E – 33°07.739’N, 133°37.829’E, depth = 577–582 m, 17/June/1999.</p> <p> <b>Site.</b> Intestine.</p> <p> <b>Deposited Specimens.</b> Collector TK, holotype NSMT-Pl 5143ab, 5 paratypes NSMT-Pl 5110 & NSMT-Pl 5143ab.</p> <p> <b>Records.</b> 1. Kuramochi (2001); 2. Present study.</p> <p> <b>Descriptions.</b> 1, 2.</p> <p> <b>Re-description.</b> [Based on 1 holotype and 5 paratypes. Measurements and proportions given in Table 2.] Body elongate-oval, widest equatorially; rounded at both ends. Forebody attenuated anteriorly, narrows at oesophageal level. Hindbody rounded posteriorly, wider than forebody, with parallel margins, narrows in post-testicular region. Tegument smooth. Pre-oral lobe absent. Oral sucker subspherical, subterminal. Ventral sucker sessile, round to transversely elongate, wider than long in most specimens, larger than oral sucker, post-bifurcal, pre-equatorial and located near junction of anterior and middle thirds of body. Prepharynx short in 67% [n=4] of specimens and indistinct in 33% [n=2] of specimens. Pharynx muscular, dolioform, wider than long in 50% [n=3] of specimens. Oesophagus thick-walled, straight to somewhat sinuous. Intestinal bifurcation anterior to ventral sucker by holotype 208 (mean 194, range 104–424) [n=5] long. Ceca narrow, run posteriorly along lateral sides of worm, end blindly near posterior extremity; cecal ends arcuate.</p> <p> Parasite <i>T. katadara T. katadara T. katadara</i> n = 1 4 1</p> <p>Taxonomic status Holotype Paratypes Paratype Source of data NSMT-Pl 5143ab1 NSMT-Pl 5143ab1 NSMT-Pl 5110 1 Length 2,640 1,640–1,740 (1,690)2 4,320 Width at pharynx 536 360–560 (452) 820</p> <p>Width at VS2 928 576–864 (702) 1,360 Width at PT2 1,000 640–896 (740) 1,280 Forebody L2 740 540–580 (560) 1,340 Hindbody L 1,520 840–900 (857) 2,500 Oral sucker (OS) L 240 184–208 (196) 328</p> <p>OS W2 288 220–288 (244) 352</p> <p>Prepharynx L 0 0–20 (15) 48</p> <p>Pharynx L 100 80–148 (115) 144</p> <p>Pharynx W 112 84–104 (95) 192</p> <p>Oesophagus L 220 148–208 (180) 376</p> <p>VS L 408 268–324 (292) 488</p> <p>VS W 460 336–424 (370) 464</p> <p>Post-cecal region L 184 84–124 (99) 280</p> <p>AT 2 L 248 160–200 (183) 408</p> <p>AT W 552 376–520 (422) 800</p> <p>PT L 264 204–240 (223) 432</p> <p>PT W 520 368–480 (417) 640</p> <p>AT to PT 0 0 0</p> <p>Post-testicular region (PTR) L 488 232–280 (254) 584</p> <p>PTR W at mid-point 760 456–680 (548) 936</p> <p>Cirrus pouch (CP) L 356 246–500 (335) 792</p> <p>CP W 152 100–156 (128) 216</p> <p>CP overlap VS 0 0–152 (65) 208</p> <p>Ejaculatory duct W in distal CP 10 8–10 (9) [n=3] 12</p> <p>Genital pore to lateral margin 176 108–148 (130) 224</p> <p>Pre-ovarian region L 1,420 888–960 (927) 2,660 Ovary (OV) L 232 116–172 (139) 280</p> <p>OV W 428 264–436 (325) 432</p> <p>VS to OV 272 80–168 (122) 860</p> <p>Vitellarium L 68–136 (102) [n = 5]2 32–88 (54) [n=20]2 76–196 (122) [n=5]2 Vitellarium W 52–64 (56) [n=5] 16–48 (31) [n=20] 44–96 (70) [n=5] Vitelline reservoir L 34 72–82 (77) [n=2] Not observed Vitelline reservoir W 20 64–72 (68) [n=2] Not observed Uterus L 960 512–640 (580) 1,840 Uterus W 672 344–624 (421) 860</p> <p>Post-uterine region (PUR) L 1,140 664–720 (687) 1,600</p> <p> <i>......continued on the next page</i> 1These specimens were collected and described by TK as <i>Plagioporus katadara</i> Kuramochi, 2001 in Kuramochi (2001, pp. 23–25, Figs. 7–9) and housed in the National Museum of Nature and Science, Tokyo, Japan (NSMT), under these accession numbers.</p> <p>2AT, anterior testis; L, length; PT, posterior testis; VS, ventral sucker; W, width; range with mean in parentheses; number [n] of measurements if different from total number of worms examined.</p> <p>3 Proportion of body length.</p> <p>Testes 2, tandem, smooth to lobed, transversely elongate, contiguous, median, intercecal, post-equatorial mainly in posterior third of body. Post-testicular region occupies posterior fifth of body. Cirrus pouch thin-walled, distinct, clavate, oriented transversely along lateral axis from near midline anterosinistrally to point midway between left body margin and midline proximate to left cecum, post-bifurcal; distal portion pre-acetabular; posterior extent of proximal portion variable and continues to either anterior margin of ventral sucker or extends as far as 1/2 length of ventral sucker. Seminal vesicle voluminous, bipartite; posterior proximal portion wide, saccate, convoluted; anterior distal portion tubular, narrow, passes in nearly straight line anterosinistrally before it turns sharply to right to proceed short distance into small, circular genital atrium. Prostate gland-cells distinct, numerous throughout cirrus pouch with densest number in distal portion of pouch. Pars prostatica conspicuous, thick-walled, nearly straight, 100 (121, 72–200) [n=3] long × 44 (27, 24–28) [n=3] wide, in distal portion of cirrus pouch; ejaculatory duct narrow, distinct, with cirrus present. Genital pore post-bifurcal, pre-acetabular by 180 (205, 124– 416) [n=5] long, submedian, sinistral, midway between left body margin and midline of worm, ventrally overlaps left cecum or located immediately sinistral to left cecum.</p> <p> Ovary 3- to 4-lobed, median to dextrally submedian, pre-testicular, contiguous with anterior testis, in posterior middle third of body. Mehlis’ gland conspicuous, cells numerous, located anterodorsal to anterior margin of ovary and extends posteriorly to mid-level of ovary in some individuals. Seminal receptacle distinct, canalicular, sinistral to ovary and midline of worm. Laurer's canal opens dorsal and medial to left cecum; canal itself conspicuous, long, thick-walled, runs along anterior margin of ovary, mostly straight until near opening where it loops; lateral half of canal in holotype dilated in 2 places where filled with sperm. Oviduct loops once or twice as it proceeds anteriorly from anterior margin of ovary. Vitellarium circumcecal, follicles numerous, subspherical or oblong or irregular in shape; anterior extent of vitellarium in forebody as 2 separate “bunches” (i.e. <i>Tellervotrema</i> vitellarium distribution) distributed from near level of intestinal bifurcation (one individual with a few follicles on left side slightly anterior to bifurcation) posteriorly either to anterior margin of ventral sucker or to mid-level of latter; posterior extent of vitellarium in hindbody along lateral margins from level of posterior margin of ventral sucker to posterior extremity, not confluent but encroaches over lateral margins of gonads, immediate pre-ovarian region, space between ovary and anterior testis and into inter-testicular area, completely confluent in post-testicular region. Vitelline reservoir small, sinistrally submedian, directly anterior to left lobe of ovary. Vitelline ducts indistinct, pass medially at level near ovary. Uterus intercecal, winds in wide loops to fill up almost entire space between ovary and ventral sucker; proximal loops run anteriorly from mid-level of ovary, narrows and passes dorsal to ventral sucker; distal loop turns anterosinistrally and runs parallel along left side of cirrus pouch before it loops anteriorly to terminate at genital pore. Metraterm thick-walled, mostly straight, runs parallel to left side of cirrus pouch before distal end curves around anterodextrally to enter genital atrium. Eggs oval, moderate in size and number, many collapsed or crenulated, amber, non-filamented, operculate, with conspicuous knob or boss on one pole.</p> <p>Excretory vesicle tubular, I-shaped, anteriormost extent of vesicle obscure in 50% [n=3] of specimens but observed to extend at least to posterior testis [n=2] and anterior testis [n=1]. Excretory pore dorsal, subterminal.</p> <p> <b>Remarks.</b> These specimens belong in the Plagioporinae Manter, 1947 because they possess a well-developed cirrus pouch that encloses a seminal vesicle and have a canalicular seminal receptacle. Based on Cribb (2005), these same specimens can be identified as belonging to the genus <i>Tellervotrema</i> by the presence of the following combination of diagnostic characteristics: non-filamented eggs that are> 40 Μm long (ours ranged from 70–82 long); blind ceca; an elliptical, non-pedunculate ventral sucker that lacks lamellar lips, “fleshy folds” or an accessory attachment organ; vitellarium that extend to the posterior end of the body, well into the forebody, and are interrupted at the level of the ventral sucker; tandem and paired testes; an oral sucker that is not funnel-shaped; an excretory vesicle that is not diverticulate and does not extend to the pharynx but terminates inside the hindbody at about the level of the ovary (anterior extent of excretory vesicle was obscure in our specimens, but it extended to anterior testis [cf. about level of ovary] in one individual); a clearly submedian genital pore; a pre-testicular uterus; and our specimens parasitized a macrourid species (<i>G. colletti</i>).</p> <p> As mentioned above, <i>T. katadara</i> was suppressed by Kuramochi (2011). For this study, we examined the specimens of <i>Plagioporus katadara</i>, <i>Tellervotrema katadara</i> and <i>Tellervotrema beringi</i> used by Kuramochi (2001, 2009, 2011). We have concluded that the specimens of “ <i>T. beringi</i> ” documented by Kuramochi (2011) from the pyloric ceca of the short-tailed grenadier, <i>Nezumia proxima</i>, from Sagami Bay, Japan, are in fact a new species of <i>Allopodocotyle</i> Pritchard, 1966, which we have described in another report (see Blend <i>et al</i>. 2015), and as a result, they will not be considered further in this report. We have also concluded that the specimens of “ <i>T. katadara</i> ” documented by Kuramochi (2009) from the intestine of the longfin grenadier, <i>Coryphaenoides longfilis</i>, from off northern Honshu, Japan, are in reality <i>T. beringi sensu stricto</i>, and we have re-described these specimens below. Thus, it is the holotype and five paratypes of “ <i>Plagioporus katadara</i> ” (NSMT-Pl 5143ab, NSMT-Pl 5110) described by Kuramochi (2001) from the intestine of the bathygadine macrourid <i>Gadomus colletti</i> from Tosa Bay, Japan, that is the present focus herein.</p> <p> Blend <i>et al</i>. (2012) concluded that six features best distinguished <i>T. armstrongi</i> and <i>T. beringi</i>. Egg size differs for <i>T. beringi</i> (100–110 long × 50–60 wide [see Mamaev 1965] and 80–102 × 40–60 [see Blend <i>et al</i>. 2012]) <i>vs T. armstrongi</i> (50.6–64 × 24–35 [see Gibson & Bray 1982] and 47.5–66 × 24–42 [see Blend <i>et al</i>. 2012]). The position of the genital pore differs for <i>T. beringi</i> (opening at the level of the intestinal bifurcation [bifurcal] but can reach the level of the posterior oesophagus [slightly pre-bifurcal]) <i>vs T. armstrongi</i> (opening at the level of about 30% of the distance between the intestinal bifurcation and the pharynx or more anterior [pre-bifurcal]) (see Gibson & Bray 1982; Blend <i>et al</i>. 2012). The posterior extent of the cirrus pouch relative to the ventral sucker and intestinal bifurcation differs for <i>T. beringi</i> (cirrus pouch terminates well posterior to the level of the intestinal bifurcation often reaching the posterior margin of the ventral sucker) <i>vs T. armstrongi</i> (cirrus pouch terminates at or just posterior to the level of the intestinal bifurcation and is entirely anterior to or only reaches to the middle of the ventral sucker) (see Gibson & Bray 1982; Blend <i>et al</i>. 2012). The testes appear to take up a much larger volume in the hindbody of <i>T. beringi vs T. armstrongi</i>, and the anterior extent of the distinctive, paired, isolated vitelline “bunches” in the forebody of the worm (referred to above as “ <i>Tellervotrema</i> vitellarium distribution”) differs between <i>T. beringi</i> (paired vitelline fields begin noticeably anterior to the intestinal bifurcation) <i>vs T. armstrongi</i> (paired vitelline fields begin at the level of the intestinal bifurcation or a short distance posterior to it) (see Mamaev 1965; Gibson & Bray 1982; Blend <i>et al</i>. 2012). Finally, Blend <i>et al.</i> (2012) noted that both species occupy a different geographic locality; <i>T. beringi</i> resides in the North Pacific Ocean (Bering Sea and off Oregon) while <i>T. armstrongi</i> inhabits the North Atlantic Ocean (off Scotland and in the Gulf of Mexico).</p> <p> The species “ <i>P. k a t a da r a</i> ” as described by Kuramochi (2001) and re-described above as <i>T. katadara</i> (see Table 2) differs from <i>T. armstrongi</i> and <i>T. beringi</i> in the combination of the six diagnostic characteristics just given. Egg size of <i>P. katadara</i> is 70–82 × 40–52, and this is intermediate in size between <i>T. beringi</i> (larger) and <i>T. armstrongi</i> (smaller). The genital pore of <i>P. katadara</i> is post-bifurcal whereas it is bifurcal in <i>T. beringi</i> and pre-bifurcal in <i>T. armstrongi</i>. In <i>P. katadara</i>, the posterior extent of the cirrus pouch is more like <i>T. armstrongi</i> in that it continues to either the anterior margin of the ventral sucker or extends as far as half the length of it, yet it is more similar to <i>T. beringi</i> in that the cirrus pouch of <i>P. k a t a da r a</i> terminates well posterior to the level of the intestinal bifurcation. The extent of the testes of <i>P. katadara</i> is more like <i>T. beringi</i> in that they take up a larger volume in the hindbody when compared with <i>T. armstrongi</i> (see Fig. 1). The anterior extent of the paired vitelline “bunches” in the forebody of <i>P. katadara</i> is to near the level of the intestinal bifurcation (like <i>T. armstrongi</i>) and not noticeably anterior to the intestinal bifurcation (like <i>T. beringi</i>). Lastly, <i>P. k a t a da r a</i> was collected from Tosa Bay, off the Pacific coast of southern Japan; a geographic locality that coincides with <i>T. beringi</i> (N. Pacific Ocean in the Bering Sea and off Oregon) and not with <i>T. armstrongi</i> (N. Atlantic Ocean off Scotland and in the Gulf of Mexico). Thus, <i>P. katadara</i> has certain features that are either completely different (e.g. position of the genital pore), or are intermediate in size (e.g. egg size), or are similar but only in part (e.g. posterior extent of cirrus pouch), when it is contrasted with <i>T. armstrongi</i> and <i>T. beringi</i>. Also evident is the similarity of <i>P. k a t a da r a</i> to <i>T. beringi</i> in testes volume in the hindbody and geographic locality, while <i>P. katadara</i> is similar to <i>T. armstrongi</i> in the anterior extent of the paired vitelline “bunches” characteristic of species of <i>Tellervotrema</i>. Given the unique combination of these differences among the six diagnostic characteristics of Blend <i>et al</i>. (2012), we hereby re-instate <i>Tellervotrema katadara</i> as a recognized species represented by the specimens originally described as <i>Plagioporus katadara</i> by Kuramochi (2001, pp. 23–24, Figs. 7–9); therefore, the total number of accepted species in <i>Tellervotrema</i> is now three.</p> <p> Our morphometric measurements of this material were close in overall comparison with those of Kuramochi (2001), but we did observe some minor differences. The oral sucker was originally described as terminal; whereas, we found it to be subterminal (see Fig. 1), and this is noticeable as well in Fig. 7 of Kuramochi (2001). The lower limits of the length (160 Μm) and width (210 Μm) of the ventral sucker given by Kuramochi (2001) were less than what we measured for this feature—268 × 336 (see Table 2), yet the sucker width ratios were unchanged. The cirrus pouch was originally described as “at [the] anterior margin of [the] acetabulum”, but we observed the posterior extent of the cirrus pouch to be variable; it continued to either the anterior margin of the ventral sucker or as far as half the length of it. We noted that the single paratype specimen of <i>T. katadara</i> (NSMT-Pl 5110) is a relatively large individual and had features with sizes consistently larger than those given by Kuramochi (2001); however, the holotype and four paratypes of <i>T. katadara</i> (NSMT-Pl 5143ab) had features that were, for the most part, quite similar in size to those in the type description (see Table 2). Finally, Kuramochi (2001) described the seminal receptacle of this species as small and weakly developed, and he illustrated this feature in the holotype (Figs 7 & 9 as “SR”) as a tiny, blind sac located at the junction of the “germiduct” (= oviduct) and the most medial part of the Laurer’s canal. We feel this feature was misinterpreted. We observed the seminal receptacle in the holotype of <i>T. katadara</i> (NSMT-Pl 5143ab) to be two distinct, sperm-filled dilations located sinistral to the ovary and midline of the worm within the lateral (not medial) portion of the Laurer’s canal (see our Fig. 3). What was described and illustrated as the seminal receptacle (“SR”) by Kuramochi (2001) was in reality an extension of the Mehlis’ gland cells and a developing egg behind the Laurer’s canal (original illustrations of holotype were in ventral view). As described above, we did see dilations along the Laurer’s canal proximate to the loop and dorsal opening (Fig. 3) that appear to be full of fluid (sperm)—the seminal receptacle. Based on the subfamily diagnosis for the Plagioporinae (see Cribb 2005), members of this group have a canalicular seminal receptacle; a seminal receptacle formed by a dilation(s) of the proximal portion of the Laurer’s canal (see Gibson & Bray 1979). Thus, our observation of the sperm-filled dilations along the Laurer’s canal within the holotype specimen of <i>T. katadara</i> is in line with typical members of this subfamily.</p>Published as part of <i>Blend, Charles K., Kuramochi, Toshiaki & Dronen, Norman O., 2015, Re-evaluation of Tellervotrema katadara (Kuramochi, 2001) Kuramochi, 2009 (Opecoelidae: Plagioporinae) and supplementary morphological data for T. beringi (Mamaev, 1965) Gibson & Bray, 1982 with new host and locality, pp. 435-451 in Zootaxa 3986 (4)</i> on pages 438-443, DOI: 10.11646/zootaxa.3986.4.3, <a href="http://zenodo.org/record/235876">http://zenodo.org/record/235876</a&gt

Re-evaluation of Tellervotrema katadara (Kuramochi, 2001) Kuramochi, 2009 (Opecoelidae: Plagioporinae) and supplementary morphological data for T. beringi (Mamaev, 1965) Gibson & Bray, 1982 with new host and locality

Blend, Charles K., Kuramochi, Toshiaki, Dronen, Norman O. (2015): Re-evaluation of Tellervotrema katadara (Kuramochi, 2001) Kuramochi, 2009 (Opecoelidae: Plagioporinae) and supplementary morphological data for T. beringi (Mamaev, 1965) Gibson & Bray, 1982 with new host and locality. Zootaxa 3986 (4): 435-451, DOI: http://dx.doi.org/10.11646/zootaxa.3986.4.

Tellervotrema Gibson & Bray 1982

Key to the species of <i>Tellervotrema</i> Gibson & Bray, 1982 <p>1. Position of genital pore bifurcal or pre-bifurcal; egg size small (47.5–66 × 24–42) or large (80–110 × 40–60); geographic locality either North Atlantic or North Pacific Oceans............................................................. 2</p> <p> - Position of genital pore post-bifurcal; egg intermediate in size (70–82 × 40–52); geographic locality in North Pacific Ocean (off Japan).......................................... <i>Tellervotrema katadara</i> (Kuramochi, 2001) Kuramochi, 2009</p> <p> 2. Anterior extent of paired vitelline “bunches” in forebody (i.e. “ <i>Tellervotrema</i> vitellarium distribution”) to level of intestinal bifurcation or short distance posterior to it; cirrus pouch terminates posteriorly at level of intestinal bifurcation or just posterior to it; egg size small (47.5–66 × 24–42); geographic locality in North Atlantic Ocean (off Scotland, Gulf of Mexico)...................................................................... <i>Tellervotrema armstrongi</i> Gibson & Bray, 1982</p> <p> - Anterior extent of paired vitelline “bunches” in forebody (i.e. “ <i>Tellervotrema</i> vitellarium distribution”) to level noticeably anterior to intestinal bifurcation (i.e. level of mid-oesophagus); cirrus pouch terminates posteriorly at level well posterior to intestinal bifurcation; egg size large (80–110 × 40–60); geographic locality in North Pacific Ocean (Bering Sea, off Oregon and Japan)........................................... <i>Tellervotrema beringi</i> (Mamaev, 1965) Gibson & Bray, 1982</p>Published as part of <i>Blend, Charles K., Kuramochi, Toshiaki & Dronen, Norman O., 2015, Re-evaluation of Tellervotrema katadara (Kuramochi, 2001) Kuramochi, 2009 (Opecoelidae: Plagioporinae) and supplementary morphological data for T. beringi (Mamaev, 1965) Gibson & Bray, 1982 with new host and locality, pp. 435-451 in Zootaxa 3986 (4)</i> on page 449, DOI: 10.11646/zootaxa.3986.4.3, <a href="http://zenodo.org/record/235876">http://zenodo.org/record/235876</a&gt

Tellervotrema beringi (Mamaev, 1965) Gibson & Bray 1982

<i>Tellervotrema beringi</i> (Mamaev, 1965) Gibson & Bray, 1982 <p>(Figs. 4–6)</p> <p> <b>Synonyms.</b> <i>Plagioporus beringi</i> Mamaev, 1965; <i>Tellervotrema katadara</i> of Kuramochi (2009).</p> <p> <b>Host.</b> <i>Coryphaenoides longifilis</i> Günther; Gadiformes: Macrouridae: Macrourinae; longfin grenadier.</p> <p> <b>Locality.</b> Off the Pacific coast of the Tōhoku region, northern Honshu, Japan, 37°47.60’N, 142°37.12’E – 37°47.4’N, 142°37.17’E (Station WA-05-F1200), depth = 1,196 m, 28/October/2005.</p> <p> <b>Site.</b> Intestine.</p> <p> <b>Deposited Specimens.</b> Collector TK, 8 vouchers NSMT-Pl 5672.</p> <p> <b>Records.</b> 1. Mamaev (1965); 2. Yamaguti (1971); 3. Gibson & Bray (1982); 4. Bray (1995); 5. Blend (1996); 6. Blend <i>et al</i>. (2012); 7. Kuramochi (2009); 8. Present study.</p> <p> <b>Descriptions.</b> 1, 6, 8.</p> <p> <b>Re-description.</b> [Based on 7 voucher specimens and 1 highly elongate and lanceolate specimen in {}. Measurements and proportions given in Table 3.] Body elongate-oval, 1 specimen highly elongate and lanceolate, widest post-equatorially; rounded at anterior and posterior extremities. Forebody attenuated anteriorly, narrows at bifurcal or oesophageal level. Hindbody rounded posteriorly and wider than forebody. Tegument smooth. Pre-oral lobe absent. Oral sucker subspherical, subterminal (terminal in 1 specimen). Ventral sucker sessile, spherical to subspherical, wider than long in most specimens, larger than oral sucker, post-bifurcal, pre-equatorial and located near junction of anterior and middle thirds of body. Prepharynx quite short, distinct. Pharynx muscular, spherical to dolioform. Oesophagus thick-walled, straight in most specimens [n=7] or slightly sinuous [n=1]. Intestinal bifurcation anterior to ventral sucker by (mean 191, range 40–272) [n=7] {336} long. Ceca narrow, run posteriorly along lateral sides of worm, end blindly near posterior extremity; cecal ends slightly arcuate and can be inflated.</p> <p> Parasite <i>T. beringi T. beringi T. beringi</i></p> <p>n = 2 20 8</p> <p> Host <i>Coryphaenoides</i> sp. Giant grenadier, <i>Albatrossia</i> Longfin grenadier,</p> <p> (Macrouridae) <i>pectoralis</i> (Gilbert) <i>Coryphaenoides longifilis</i> (Macrouridae) Günther (Macrouridae) <i>......continued on the next page</i> Parasite <i>T. beringi T. beringi T. beringi</i> 1 These specimens were collected by Dr. James M. McCauley (deceased), Oregon State University, and housed at the Harold W. Manter Laboratory (HWML), University of Nebraska, Lincoln, Nebraska, U.S.A., under these accession numbers. 2 These specimens were collected and described by TK as <i>Tellervotrema katadara</i> (Kuramochi, 2001) in Kuramochi (2009, pp. 30–31) and housed in the National Museum of Nature and Science, Tokyo, Japan (NSMT), under this accession number. 3 AT, anterior testis; L, length; PT, posterior testis; VS, ventral sucker; W, width; range with mean in parentheses; number [n] of measurements if different from total number of worms examined; one of eight specimens (NSMT-Pl 5672) appeared highly elongated and lanceolate in shape upon fixation (as opposed to elongate oval), and its measurements are included in {} to separate it from the seven others.</p> <p>4 Proportion of body length.</p> <p>Testes 2, tandem, smooth to lobed, transversely elongate, median, intercecal, post-equatorial mainly in posterior third of body, contiguous [n=3] or slightly separated [n=5]. Post-testicular region fairly sizeable, occupying posterior fourth of body. Cirrus pouch thin-walled, clavate, mostly pre-acetabular, extends anterosinistrally from midline to point about midway between midline and left margin, distinctly elongate in anterior portion with conspicuous sinistral turn over left cecum and toward left margin of worm in some individuals [n=4]; anterior extent of distal portion to level of intestinal bifurcation [n=6] or slightly posterior to bifurcation [n=2]; posterior extent of proximal portion either just overlaps anterior margin of ventral sucker [n=6] or extends to mid-level of latter [n=2]. Seminal vesicle bipartite; proximal portion saccular, convoluted; distal portion tubular, narrow, straight; terminates in small, circular, distinct genital atrium. Prostate gland-cells well developed, numerous in cirrus pouch with especially dense number in distal portion of pouch. Pars prostatica conspicuous, thick-walled, with numerous cells along walls, (67, 46–84) [n=7] {70} long × (27, 18–32) [n=7] {24} wide, in distal portion of cirrus pouch; ejaculatory duct distinct, straight, (66, 40–96) [n=5] {80} long. Genital pore submedian, sinistral, midway between left body margin and midline (located just left of midline in highly elongate/ lanceolate specimen), at level of intestinal bifurcation but can reach level of posterior oesophagus (post-bifurcal in highly elongate/lanceolate specimen), pre-acetabular by (311, 264–360) [n=7] {284} long, ventrally overlaps left margin of left cecum or short distance lateral or medial to left cecum, closer to ventral sucker than oral sucker.</p> <p> Ovary moderate to deeply 3- to 4-lobed, compressed longitudinally in some individuals [n=4], median to dextrally submedian, intercecal, immediately pre-testicular, contiguous with anterior testis, post-equatorial in posterior portion of middle third of body. Oötype median, directly anterodorsal to ovary, anterior to anterodextral to vitelline reservoir. Mehlis’ gland cells conspicuous, numerous, overlapped by loops of uterus. Seminal receptacle canalicular, elaborate, overlaps left lobe of ovary and fills up large portion of Laurer’s canal via distinct swellings/ dilations in canal (cf. beads on a string) primarily anterosinistral to ovary. Laurer's canal with dorsal opening, (98, 68–128) [n=2] medial to left cecum (canal opening dorsally overlaps posterior margin of vitelline reservoir in highly elongate/lanceolate specimen), opening surrounded by dark-stained cells; canal itself extensive, convoluted, overlaps Mehlis’ gland-oötype complex and loops just before entering latter. Oviduct convoluted, arises from midline of ovary along its anterior margin. Vitellarium circumcecal, follicles numerous, circular or elongate oval or globular in shape, variable in size; anterior extent of vitellarium in forebody as 2 separate but at times indistinct “bunches” (i.e. <i>Tellervotrema</i> vitellarium distribution) distributed from level of mid-oesophagus to level of posterior margin of ventral sucker, interruption in vitelline fields proximate to ventral sucker variable in number (0, 1 or 2 gaps), symmetry (gaps directly opposite ventral sucker, oblique to ventral sucker, or displaced longitudinally [highly elongate/lanceolate specimen with large gap in vitellarium in posterodextral region of worm]) and location (near body margin or displaced medially to near midline of worm towards and around ventral sucker); posterior extent of vitellarium in hindbody along lateral margins from level either near posterior margin of ventral sucker or between ventral sucker and ovary to posterior extremity, not confluent but encroaches over lateral margins of gonads, somewhat into immediate pre-ovarian region, space between ovary and anterior testis and into intertesticular area, completely confluent in post-testicular region [n=4] except over excretory vesicle [n=4]. Vitelline reservoir subtriangular, median to sinistrally submedian, indistinct in some individuals, directly dorsal to left lobe of ovary or anterodorsal to ovary or overlaps anterior margin of ovary. Vitelline ducts pass medially at level of anterior margin of ovary or just posterior to it. Uterus winding, intercecal, some loops pass ventrally over ceca but not lateral to them, fills up almost entire space between ovary and ventral sucker; wide proximal loops run anteriorly from ovary to posterior margin of ventral sucker then narrow and pass anterodorsal to either center or left margin of ventral sucker; distal loop turns anterosinistrally to run parallel along left side of cirrus pouch to terminate at genital pore. Metraterm indistinct, 142 [n=1] {70} long × 30 [n=1] {16} wide. Eggs smooth, oval, majority collapsed or crenulated, amber, non-filamented, operculate, with conspicuous knob or boss on one pole.</p> <p>Excretory vesicle tubular, I-shaped, thin in width, extends to ovary along midline of worm. Excretory pore dorsal, subterminal, opens via a small sphincter; dark-stained cells surround pore and base of vesicle.</p> <p> <b>Remarks.</b> The eight studied specimens conform to the diagnosis of the subfamily Plagioporinae and the genus <i>Tellervotrema</i> (macrourid host species = <i>Coryphaenoides longifilis</i>) by Cribb (2005). Kuramochi (2009, p. 30–31) gave a rudimentary description of these same specimens (originally identified as <i>T. katadara</i>) providing only a range of body lengths and widths (3.00–3.18 mm × 1.16–1.35 mm). He even stated that “… <i>T. katadara</i> may be closely related to <i>T. beringi</i> so far [as] measurements are concerned.”</p> <p> This material compares well overall with the type description of <i>T. beringi</i>, originally described by Mamaev (1965) as <i>Plagioporus beringi</i> Mamaev, 1965, from the stomach of seven specimens of an unidentified macrourid of the genus <i>Coryphaenoides</i> Gunnerus obtained at 150–500 m depths from 30 miles west of the Pribilof Islands, Alaska, and from near Cape Navarin, Russia, in the Bering Sea. When compared to the type description of <i>T. beringi</i>, we noted a few minor morphometric differences: the prepharynx of <i>T. beringi</i> in the original description was more distinct and longer (110 Μm <i>vs</i> 12–36 Μm); the pharynx had a slightly larger width (200 <i>vs</i> 112–144); the testes were larger (anterior testis: 360 × 780 <i>vs</i> 208–264 × 480–576; posterior testis: 380 × 750 <i>vs</i> 240–304 × 456– 608); the cirrus pouch had a slightly longer length (600 <i>vs</i> 388–476); and the ovary width was slightly smaller (340 <i>vs</i> 376–552). Blend <i>et al</i>. (2012) reported individuals of <i>T. beringi</i> in the intestine of the giant grenadier, <i>Albatrossia pectoralis</i> (Gilbert), and <i>Coryphaenoides</i> sp. obtained from depths of 1,530 m and 2,800 m, respectively, in the northeastern Pacific Ocean off Oregon. The eight specimens of <i>T. beringi</i> re-described from <i>C. longifilis</i> here and in Table 3 have a slightly wider body, slightly wider testes and ovary, a longer distance between the ventral sucker and ovary, and larger vitelline follicles and uterus width; however, all other morphometric measurements for the present material along with the six proportions of body lengths (%) and two ratios given in Table 3 compare well to the specimens of <i>T. beringi</i> re-described by Blend <i>et al</i>. (2012).</p> <p> The present material differs slightly from earlier descriptions of <i>T. beringi</i> in the posterior extent of the cirrus pouch relative to the ventral sucker and intestinal bifurcation. Mamaev (1965) reported the cirrus pouch of this species to reach to the posterior margin of the ventral sucker, and Blend <i>et al</i>. (2012) described it to at least overlap 1/5 to 3/4 the length of the ventral sucker and terminate well posterior to the level of the intestinal bifurcation. In these specimens, the posterior extent of the cirrus pouch just overlaps the anterior margin of the ventral sucker [n=6, 75%]—more like <i>T. armstrongi—</i> or extends to the mid-level of the ventral sucker [n=2; 25%]—like either <i>T. armstrongi</i> or <i>T. beringi</i> —and it terminates well posterior to the level of the intestinal bifurcation (see Blend <i>et al</i>. 2012).</p> <p> Blend <i>et al.</i> (2012) commented that the testes texture of <i>T. beringi</i> from their material ranged from irregularly indented to deeply lobed; none were smooth as illustrated by Mamaev (1965, Fig. 1) in the original description of this species. There were specimens in this study that possessed smooth testes, and we feel that this observation further supports the possibility of a high degree of plasticity in this feature within species of <i>Tellervotrema</i>; an idea first hypothesized by Blend <i>et al.</i> (2012, Figs. 20–23), who on combining their observations of this feature with those of Mamaev (1965), concluded that testes texture of <i>T. beringi</i> can vary from smooth to irregularly indented to deeply lobed. Blend <i>et al.</i> (2012) also observed in <i>T. beringi</i> the characteristic vitellarium gap (separating the paired, isolated vitelline “bunches” in the forebody from the remainder of the vitellarium in the hindbody—this gap is characteristic of species of <i>Tellervotrema</i>) at about the level of the posterior margin of the ventral sucker. However, the gap itself was quite variable in number (0, 1 or 2 gaps), symmetry (gaps directly opposite ventral sucker, oblique to ventral sucker, or displaced longitudinally to near level of gonads) and location (near body margin or displaced medially to near midline of worm) (see Blend <i>et al</i>. 2012, Figs. 11–16). This same variability in number, symmetry and location of the vitelline gap was seen in the present material of <i>T. beringi</i> from off Japan. Specifically, the gap in the vitelline fields proximate to the ventral sucker varied in number (0, 1 or 2 gaps), symmetry (gaps directly opposite ventral sucker, oblique to ventral sucker, or displaced longitudinally [the highly elongate/lanceolate specimen possessed a large gap in the vitellarium within the posterodextral region of the worm]) and location (near body margin or displaced medially to near midline of worm towards and around ventral sucker).</p>Published as part of <i>Blend, Charles K., Kuramochi, Toshiaki & Dronen, Norman O., 2015, Re-evaluation of Tellervotrema katadara (Kuramochi, 2001) Kuramochi, 2009 (Opecoelidae: Plagioporinae) and supplementary morphological data for T. beringi (Mamaev, 1965) Gibson & Bray, 1982 with new host and locality, pp. 435-451 in Zootaxa 3986 (4)</i> on pages 443-448, DOI: 10.11646/zootaxa.3986.4.3, <a href="http://zenodo.org/record/235876">http://zenodo.org/record/235876</a&gt

FIGURES 4–6 in Re-evaluation of Tellervotrema katadara (Kuramochi, 2001) Kuramochi, 2009 (Opecoelidae: Plagioporinae) and supplementary morphological data for T. beringi (Mamaev, 1965) Gibson & Bray, 1982 with new host and locality

FIGURES 4–6. Tellervotrema beringi (Mamaev, 1965) Gibson & Bray, 1982 from the longfin grenadier, Coryphaenoides longifilis Günther. 4. Composite drawing of whole specimen, dorsal view (Note: Ceca are dorsal to features herein but are illustrated ventral for ease of observation). 5. Male terminal genitalia, ventral view. 6. Composite drawing of oötype region, dorsal view (Note: Oviduct is ventral to transverse vitelline ducts but illustrated dorsal to view former). Abbreviations: At, anterior testis; C, cecum; Cp, cirrus pouch; Dsc, dark-stained cells; E, egg; Ep, excretory pore; Ev, excretory vesicle; Gp, genital pore; Lc, Laurer's canal; M, metraterm; Mg, Mehlis' gland; O, ovary; Oes, oesophagus; Os, oral sucker; Ov, oviduct; P, pharynx; Pc, prostate gland-cells; Pp, pars prostatica; Pt, posterior testis; Sr, seminal receptacle; Sv, seminal vesicle; U, uterus; V, vitelline follicles; Vd, vitelline duct; Vr, vitelline reservoir; Vs, ventral sucker. Scale-bars: 4, 350 µm; 5, 185 µm; 6, 135 µm

Feeding habits of Dall's porpoises (Phocoenoides dalli) in the subarctic North Pacific and the Bering Sea basin and the impact of predation on mesopelagic micronekton

We investigated the stomach contents of Dall's porpoises collected in pelagic waters spanning most of their range in the North Pacific and the Bering Sea. Analysis revealed the porpoises fed mainly on myctophid fishes in the subarctic North Pacific and on gonatid squids as well as myctophid fishes in the Bering Sea. Most of the prey items were mesopelagic micronekton, primarily fishes and squids that migrate vertically to shallower waters at night. Stomach content was greater during twilight hours, suggesting the porpoises foraged actively on myctophids at night in shallower waters. Stomach contents were strongly characterized by local mesopelagic prey fauna, and prey species selectivity was not apparent. The annual consumption by Dall's porpoises was estimated to be 2.0–2.8 million tons, or 4.7–6.5% of the biomass of mesopelagic fishes in the subarctic North Pacific, and may account for approximately 24–33% of the overall mortality of mesopelagic micronekton, especially myctophids. Myctophids are also common, but less important, prey of other subarctic predators. Dall's porpoises are likely the primary consumers of myctophids in the subarctic North Pacific. Since myctophids are the major component of the mesotrophic level, the trophic relationship between myctophids and Dall's porpoises is thought to be an important pathway of mass and energy in the pelagic food web in the subarctic North Pacific