Ptilocrinus (Chambersaecrinus) brucei Vaney

Roux, Michel, 2015, Crinoids of the stalked family Hyocrinidae (Echinodermata) collected by the USNS Eltanin in the Southern Ocean, Zootaxa 3990 (3), pp. 381-409 : 395-405

publication ID

https://doi.org/ 10.11646/zootaxa.3990.3.4

publication LSID

lsid:zoobank.org:pub:08B0220E-DC57-439C-A5B7-706B2202B1A1

DOI

https://doi.org/10.5281/zenodo.6095279

persistent identifier

https://treatment.plazi.org/id/03FFAD25-FFD4-FFE1-5483-FF4DAA60FBBF

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scientific name

Ptilocrinus (Chambersaecrinus) brucei Vaney
status

 

Ptilocrinus (Chambersaecrinus) brucei Vaney View in CoL in Wilton, 1908

Figures 9–16 View FIGURE 9 View FIGURE 10 View FIGURE 11 View FIGURE 12 View FIGURE 13 View FIGURE 14 View FIGURE 15 View FIGURE 16 , Tables 9–15 View TABLE 9 View TABLE 10 View TABLE 11 View TABLE 12 View TABLE 13 View TABLE 14 .

Synonymy: Ptilocrinus brucei Vaney in Wilton, 1908: fig. 70, pl. 23; Vaney & John, 1939: 661–664, 1 pl.; A.H. Clark, 1915: 161; Smaldon et al., 1976: 74; Roux, 1980b: 36, 41, 53, pl. 3 (figs. 5–6); Roux et al., 2002: 822. P. (Chambersaecrinus) brucei: Mironov & Sorokina, 1998: 52 –55, fig. 19–20, pl. 8 (figs. 4–5); Roux & Lambert, 2011: 45, 48, 51; Eléaume et al., 2014: 210–211.

P. (Chambersaecrinus) flexibilis Mironov & Sorokina, 1998: 55 View in CoL –57, fig. 21, pl. 11 (fig. 2).

Holotype. NMS 1921.143.1743, S. Y. Scotia , sta. 301, NW Weddell Sea, 64°48’S – 44°26’W, depth 4,585 m (2,485 fms).

Material examined. NHM 1939.5.13.1 (paratype), S. Y. Scotia , trawl 3426, off South Orcade Islands, 62° 10’S, 41° 20’ W, depth 3,245 m (includes note by D. John in 1938: specimen was “broken into small species but among them some individual plates, radials, etc.. are recognizable”.); USNM 1005433, South East Pacific basin, 63°0.3’to 63°12.0’S –128°12’ to 128°11’W, depth 4,682 m (2 specimens; 1 with theca, proximal arm and stalk; 1 juvenile with complete stalk, basal ring and fragments of proximal arms and radials); USNM 1005438, South Atlantic Ocean, Scotia Sea , South Georgia Island, 54°00’– 54°05’S, 33°40’– 33°43’W, depth 2663–2718 m (1, partly fragmented, theca poorly preserved, fragments of proximal arms with radials); USNM 1005439, South Atlantic, Scotia Sea , NE of South Shetland Islands, 59°S– 51.9°W, depth 3,010–3,510 m (1 theca, proximal arms and stalk fragments); USNM 1105453-A South Orkney Islands, Scotia Ridge , 62°09’ à 62°16’S –38°11’ à 38°24’W, depth 3,056–3,459 m (dissociated radials, basal ring, proximal brachials and proximalmost columnals).

Emended diagnosis. A species of Ptilocrinus (Chambersaecrinus) reaching large size; proximalmost stalk diameter to 4.5 mm, arm length to 130 mm with about 40 pinnules on each side, and pinnule length to 55 mm. External morphology variable; ratio of cup height to adoral diameter 0.97–1.36; ratio of cup to radial height 1.01– 1.65 (usually 1.20–1.34); ratio of radial to first brachial width 1.45–1.97; ratio of adoral cup to proximalmost stalk diameter 3.25 (small specimen) to 4.27 (usually 3.97–4.20); arm deeply inserted on adoral radial edge; basal cup and proximalmost stalk diameter usually equal; maximum ratio of columnal height to diameter in a given stalk from 1.43 in smallest specimen to 0.41 in large specimens. Tegmen inflated and rounded; anal cone significantly taller than oral cone and reaching level of Br8 to Br 14 in large specimens; base of anal cone peripheral on tegmen; upper part of cone oriented toward tegmen center; orals smooth and concave with rounded top; as many as 20 large polygonal tegminal plates sometimes with a regular median arrangement. Arm pattern variable, from chiefly alternating free brachial and brachial pairs to long series (more than 20) of successive free brachials beyond the third brachial pair; proximalmost arm pattern 1+2 3 4 5+6 7 (75.9%), 1+2 3 4 5+6 7+8 (13.8%); first pinnule usually on Br4 (94.7%), rarely on Br5; most frequent brachial pairs beyond Br7 at 8+9 (44.0%), 10+11 (22.7%) and 18+19 (27.3%). Brachial muscular synarthry with conspicuous process prolonging adoral groove. Pinnule inserted on distal adoral side of brachial; proximal part with asymmetrical genital inflation; great number of additional small proximal plates decreasing distally; additional plates imbricated or irregularly aligned.

Stalk symplexies with 6 (young stage) to 14 (usually 8–12) crenular units of 1 crenula of various lengths; up to 3 crenulae or subsidiary crenulae developed between units in large specimens; axial canal in proximal mesistele enlarges substantially during ontogeny; lumen bordered by coarsely-meshed galleried stereom; distal syzygies with thin irregular radial crenularium.

Description. Tables 9 View TABLE 9 and 10 View TABLE 10 list biometric parameters, including holotype and paratype. The small number of specimens and the wide range of character variations preclude obtaining robust results from statistical analyses on the main changes in quantitative ratios during ontogeny.

USNM 1005439: Theca well preserved with proximal and mid arms ( Fig. 9 View FIGURE 9 A–B) strikingly resembling the original figure of the holotype ( Wilton 1908; Vaney & John 1939). Tegmen inflated and rounded; high anal cone reaching level of Br14, significantly taller than oral cone; base of anal cone peripheral on tegmen; upper portion of cone oriented toward tegmen center ( Fig. 9 View FIGURE 9 A–B); orals subvertical, smooth and concave with rounded tip; as many as 20 large polygonal tegminal plates without peculiar median arrangement in inter-rays ( Fig. 9 View FIGURE 9 B); inter-rays A–B, C–D, A–E wider than the two other inter-rays; hydropores on adoral quarter of tegmen; conspicuous ambulacral “bridges” between Br10–11 and top of oral cone with cover plates in a gathered arrangement; outer ramifications of “bridges” corresponding to proximal pinnules not attached to tegmen.

Proximal arm pattern 1+2 3 4 5+6 7 (5 cases) with first pinnule on Br4; brachial pair at 8+9 (3 cases) and 9+10 (1); number of successive muscular synarthries beyond the last brachial pair and before broken end: 6 (2 cases), 8 (1), 24 (1), and 16 including Br7 (1). Two ossicles of a brachial pair united by flat synostosis. Pinnule socket in distal half of brachial adorally ( Fig. 10 View FIGURE 10 A–B); transverse muscular synarthry uniting pinnule to arm with marked fulcral ridge and deep muscular fossa on brachial ( Fig. 10 View FIGURE 10 E–F); free brachial with strongly oblique muscular articulations ( Fig. 10 View FIGURE 10 B); muscular synarthries with ambulacral groove forming a conspicuous adoral process in mid-articulation ( Fig. 10 View FIGURE 10 C–D). Adoral proximal arm inflated with numerous lateral plates not aligned, and conspicuous festooned cover plates in a gathered arrangement; proximal part of pinnules with proximal genital inflation of asymmetric, multiplated architecture, and cover plates poorly differentiated ( Fig. 11 View FIGURE 11 A–B); 3 (maximum 4) irregular plate rows on convex side decreasing to 1 row distally ( Fig. 11 View FIGURE 11 B); concave side without rows; lateral plates small or disappearing in mid arm with cover plates rounded or elliptical; muscular synarthries of first pinnular with brachial ( Fig. 10 View FIGURE 10 E) and with second pinnular ( Fig. 11 View FIGURE 11 E) having perpendicular fulcral ridge allowing wide amplitude of movements; symmetrical synostosis between second and third pinnular ( Fig. 11 View FIGURE 11 F–G); following pinnulars asymmetrical, supporting genital inflation ( Fig. 11 View FIGURE 11 H–I); pinnulars becoming more symmetrical distally.

Length of proximal stalk attached to aboral cup 5.0 mm with 10 columnals; proximalmost diameter 3.4 mm; cup aboral diameter 3.4 mm; stalk distal diameter 3.0 mm. Stalk fragment with distal proxistele and transition to mesistele: length 17.05 mm with 22 columnals; proximal diameter 2.95 mm with maximum columnal height 0.9 mm, and symplexy with 11 crenular units of 2–3 crenulae (fig. 12 B–C); distal diameter 2.8 mm with maximum columnal height 1.6 mm and symplexy with 11 crenular units of 1 robust crenula ( Fig. 12 View FIGURE 12 D); inner areola and probably claustrum depressed proximally (diameter 1.3 mm), with round lacuna of diameter 0.5 mm; inner areola surrounded by coarsely-meshed stereom; stereom of depressed area progressively resorbed distally, resulting in a larger axial canal (diameter 1.0 mm) ( Fig. 12 View FIGURE 12 B–D); ratio of axial canal to columnal diameter in this fragment from 0.44 (proximal) to 0.36 (distal).

USNM 1005438: Large specimen in fragments, lacking aboral cup: radials attached to arms, fragment of inflated tegmen and tall anal tube, and complete stalk except proximalmost columnals. Proximal arm pattern 1+2 3 4 5+6 7 8 with first pinnule on Br4 (5 cases), brachial pair at 9+10 (1), 10+11 (2), and no other brachial pair (1); fifth arm broken after Br8; mid arm with free brachial only; maximum number of muscular articulations before broken end 21; distal arm fragments rarely with one brachial pair; muscular articulations oblique beyond Br4; Br1 to Br3 with lateral wings. Height and width of brachials moderately decreasing from Br1 to Br3 and very little beyond Br3 ( Table 11 View TABLE 11 ). Arms attached to tegmen to Br9; adoral face of arm inflated and multiplated, with festooned cover plates in a gathered arrangement; genital inflation of some pinnules with numerous imbricated irregular polygonal plates not in rows ( Fig. 11 View FIGURE 11 C), covering exceptionally preserved gonads with oocytes of 100– 150µ ( Fig. 11 View FIGURE 11 D); other pinnules with asymmetric architecture described above; arm and pinnule articulations as in previous specimen.

Remaining stalk length 386 mm (five fragments without gap); Table 12 View TABLE 12 lists quantitative columnal parameters; columnal diameter increasing rapidly at distal end suggesting stalk broken close to attachment disk. Proximalmost columnal with 14 crenular units (poorly preserved); number of crenular units decreasing to 12 of one crenula in proximal mesistele ( Fig. 13 View FIGURE 13 A), to 11 with numerous subsidiary crenulae in mid mesistele ( Fig. 13 View FIGURE 13 B), and to multiradiate symplexy with initially 10 crenular units observed at center in distal mesistele ( Fig. 13 View FIGURE 13 C); transition symplexy/syzygy ( Fig. 13 View FIGURE 13 D) with development of syzygial stereom on facet surface ( Fig. 13 View FIGURE 13 E) indicating short dististele (30–40 mm) with anchylosed articulations; distalmost columnals with facet entirely covered by syzygial stereom, juvenile symplexial pattern of 6 small crenular units of 1 crenula and pentalobate lumen at center ( Fig. 13 View FIGURE 13 F). Axial lumen diameter to 1.8 mm proximally; ratio of lumen to columnal facet diameter 0.45 in proxistele and proximal mesistele, decreasing slowly to 0.25 in distal mesistele and rapidly to 0.09 in dististele. From distal proxistele to mid mesistele, axial canal surrounded by galleried stereom of large meshes bordering small deep ligamentary pits fused with lumen and alternating with crenular units ( Fig. 13 View FIGURE 13 G–H and J–K); pit floor corresponding to depressed inner areola (see below specimen 1005433B, Fig. 14 View FIGURE 14 D); this character disappearing in distal mesistele ( Fig. 13 View FIGURE 13 I and L) and dististele.

USNM 1005433-A: Aboral cup tall; radials more than three times taller than broad ( Fig. 9 View FIGURE 9 C). Tegmen inflated to Br4 or more proximally; about 10 tegminal plates per inter-radius; ambulacral “bridges” between Br8 and mouth with festooned cover plates in a gathered arrangement; oral cone shorter than anal cone; orals smooth and slightly concave; top of oral cone flat. Pattern of proximal arms attached to theca 1+2 3 4 5+6 7 (2 cases) and 1+2 3 4 5+6 7 8+9 10 (3) with first pinnule on Br4; brachial pair following Br10 either 11+12 (1 case) or 15+16 (1). Radial and proximalmost brachial articulations as in USNM 1005453 (see description below).

Length of preserved stalk 23.0 mm; proximalmost diameter 2.8 mm, decreasing to 2.4 (ratio of columnal height to diameter 0.42) at distal broken end; proximalmost symplexies with 9 crenular units of 1–2 crenulae ( Fig. 14 View FIGURE 14 A–C); ratio of claustrum to columnal diameter up to 0.54; tallest columnals (first order in growth sequence) showing formation of a large axial canal with perilumen underlined by large stereom meshes ( Fig. 14 View FIGURE 14 A).

USNM 1005433-B: Juvenile specimen of proximal stalk diameter 1.9 mm, 89.5 mm long, allowing observation of a young stage of stalk ontogeny along stalk length. Table 13 View TABLE 13 lists quantitative morphological parameters. Columnal slightly barrel-shaped ( Fig. 14 View FIGURE 14 F) having maximum height in mid stalk with ratio of height to diameter up to 1.43. Symplexies with 8 crenular units of 1 short crenula ( Fig. 14 View FIGURE 14 D–E); inner areola more depressed proximally than distally; ratio of depressed areola to facet diameter 0.46–0.54; axial canal perilumen marked by conspicuous large stereom meshes; claustrum in proximal columnal with pentalobate to multilobate lumen; thin multiradiate syzygial crenularium developing in distal mesistele ( Fig. 14 View FIGURE 14 E–F).

USNM 1005453: Badly preserved specimen; all ossicles dissociated; all remaining ossicles similar to those of other specimens. Proximalmost arm pattern 1+2 3 4 with first pinnule on Br4. Radial with deep arm insertion ( Fig. 15 View FIGURE 15 A); inner surface with two sub-parallel conspicuous nervous canals ( Fig. 15 View FIGURE 15 A–B); synarthry joining radial and Br1 with well differentiated inner (adoral) ligament and muscular areas ( Fig. 15 View FIGURE 15 C), this differentiation becoming less conspicuous in the following muscular synarthries ( Fig. 15 View FIGURE 15 E and G); Br3 with deep adoral groove ( Fig. 15 View FIGURE 15 G); synostoses flat; stereom of synostosis 1+2 with small meshes only on Br1 facet ( Fig. 15 View FIGURE 15 D) and small meshes aborally plus larger ones around lumen and adorally on Br2 adjacent facet ( Fig. 15 View FIGURE 15 F). Only proximalmost columnals remaining; articulations with 14 crenular units of 1 crenula with various lengths and pentalobate lumen ( Fig. 12 View FIGURE 12 A); no stereom differentiation between claustrum and inner areola.

HOLOTYPE AND PARATYPE: Quantitative parameters of the holotype and paratype listed by Vaney (in Vaney & John 1939) were usually overestimates. Mironov and Sorokina (1998) re-examined the large holotype ( NMS 1921.143.1743), which is now in poor condition. I used Vaney & John’s (1939) measurements for calibrating measurements of the large and fine original photograph of the holotype when it was still well-preserved (Vaney 1908) ( Tables 9 View TABLE 9 and 10 View TABLE 10 ). General holotype morphology is as in USNM 1005439 ( Fig. 9 View FIGURE 9 A). Each arm was about 110–130 mm long with the distal ends rolled up, about 40 pinnules on each side; maximum pinnule length 55 mm with 40 pinnulars. Proximal arm pattern 1+2 3 4 5+6 7 with first brachial on Br4 (4 cases); one arm described by Vaney with the following brachial pairs at 9+10, 16+17 24+25, 33+34, 40+41; other arms with brachial pairs at 8+9 (2 cases), 13+14, 14+15, 17+18, 18+19 (1 case each). Stalk length about 530 mm; proximalmost diameter 3.5 mm, decreasing to 3.0 at a distance of 15 mm from cup; maximum ratio of columnal height to diameter 0.71 in mid stalk.

The paratype (NHM 1939.5.13.1) is fragmented. However, proximal arm pattern reconstruction is possible: 1+2 3 4 5+6 7+ 8 9 10 +11 12 (3 cases), 1+2 3 4 5+6 7 8+9 10 11 12 +13 (1), 1+2 3 4 5 6 7 8+ 9 10 11 +12 (1); usually free brachials alternating with brachial pairs distally. Five radials preserved. Stalk very fragmented; total length of all fragments about 90 mm; proxistele lost; proximalmost diameter inferred from other stalk fragments about 2.5 mm (3.0 mm after Vaney); minimum values in proximal mesistele: columnal diameter 1.95 mm, columnal height 1.45 mm, ratio of height to diameter 0.86; maximum values in mid and distal mesistele: columnal diameter 2.2 mm, columnal height 2.5 mm, ratio of height to diameter 1.43; maximum values in distalmost fragments: columnal diameter 2.7 mm, columnal height 1.5 mm, ratio of height to diameter 0.56. Symplexies with 10–11 crenular units of 1 crenula in proximalmost fragments and coarsely-meshed stereom in inner areola and perilumen ( Fig. 16 View FIGURE 16 A); 8– 9 crenular units of 1 crenula in mid mesistele; 7 crenular units of 1 short crenula in juvenile pattern at facet center in distal mesistele ( Fig. 16 View FIGURE 16 B). Transition between mesistele and dististele with multiradiate crenularium of up to about 20 wide crenulae ( Fig. 16 View FIGURE 16 B and D); distalmost syzygies examined with numerous thinner radial crenulae becoming irregular in outer facet ( Fig. 16 View FIGURE 16 C and E).

Remarks. Mironov & Sorokina (1998) described two other poorly preserved specimens collected off the Orkney Islands by Russian cruises. The specimen attributed to P. brucei was collected at R/V Dmitri Mendeleev sta. 4094, 60°42.8’–43.1’S to 41°03.0–01.9’W, depth 4,070–4,570 m. Proximal arm patterns included two variants: 1+2 3 4 5+6 with first pinnule on Br4 (3 cases) and with one of these arms with the third brachial pair at 8+9 followed by 6 successive muscular articulations, and 1+2 3 4+5 with first pinnule on Br5 (2 cases) and with one of these arms with the third brachial pair at 7+8, number of successive muscular articulations 5–15 in mid arm fragment and 2–3 in distal arm. Anal cone height about 11.1 mm. Three stalk fragments with total length 163.2 mm ( Table 14 View TABLE 14 ); estimated proximalmost diameter about 2.7 mm; symplexies with 9–10 crenular units of 1–2 crenulae; ratio of lumen to columnal diameter 0.25 in mid stalk. The second specimen, attributed to a new species P. flexibilis Mironov & Sorokina, 1998 , was collected at R/V Akademic Kurchatov sta. 908, 60°13.5’–12.9’S to 44°10.6’– 12.2’W, depth 5,465–5,474 m (Moscow State Univ. Zoological Museum cat. no. C-20). Proximal arm patterns 1+2 3 4 5+6 7 8 (1 case) and 1+2 3 4 5+6 7+8 (1). Roux & Lambert (2011) considered P. brucei and P. flexibilis as conspecific.

The current study documents the wide range of intraspecific variation in P. (C.) brucei . Fig. 9 View FIGURE 9 illustrates the range in variation in external morphology. Arm pattern varies from chiefly alternating free brachials and brachial pairs to long series of successive muscular articulations beyond the third brachial pair ( Table 15); proximalmost arm pattern 1+2 3 4 5+6 7 (75.9%), 1+2 3 4 5+6 7+8 (13.8%); first pinnule on Br4 (94.7%); brachial pair at 8+9 (44.0%), 9+10 (13.0%), 10+11 (22.7%), 13+14 (15.0%), 15+16 (18.7%), 18+19 (27.3%), and other brachial pairs <13%. The adoral process in brachial muscular synarthries has never been described in the other species of Ptilocrinus . Genital pinnules display an asymmetrical architecture. Exceptionally preserved submature oocytes>100 µm across ( Fig. 11 View FIGURE 11 C–D) suggest that larvae could be lecithotrophic. The number of crenular units in stalk symplexies increases throughout ontogeny from 6 to 12 (possibly 14), but the rate of this change varies from an individual to another; usually each crenular unit has 1 crenula of various lengths, but sometime up to 3 crenulae or with subsidiary crenulae between units in the largest specimens. The enlargement of the axial canal in the proximal mesistele through ontogeny is also variable. Small specimens have relatively tall columnals (maximum ratio of columnal height to diameter 1.43) compared to the largest specimens (0.41). The anal cone is always significantly higher than the oral cone. The arrangement of interadial tegminal plates into a median row is irregular and frequently absent. As pointed out by Roux & Lambert (2011), this character cannot be used to identify subgenus Chambersaecrinus .

Ptilocrinus (C.) brucei View in CoL shares with P. (Ptilocrinus) clarki Roux & Lambert, 2011 View in CoL , an asymmetrical architecture in the proximal part of the genital pinnules, and, with P. (P.) amezianeae Eléaume et al., 2011 View in CoL , and Dumetocrinus antarcticus Bather, 1908 View in CoL , significant enlargement of the axial canal through ontogeny, more than 10 crenular units in symplexies of large specimens, and frequently long series of free brachials in mid arm. Roux & Lambert (2011) placed P. brucei View in CoL and P. stukalinae View in CoL within subgenus Chambersaecrinus . P. stukalinae View in CoL mainly differs in having a less inflated tegmen, cover plates with a long terminal projection, symplexies with 6–8 crenular units of 1–3 crenulae, ligamentary pits between crenular units, and without enlargement of the stalk axial canal through ontogeny.

Occurrence. Southern Ocean from 33° to 128°W and from 54° to 63°S (NW Weddell Sea; South Georgia, Orcade, Orkney and Shetland Islands; SE Pacific basin), depth 2,718 to 5,465 m (possibly 2,663 to 5,474 m).

1+2 3 4 5 6 7 8+ 9 10 11 + 12 13 14 15+16 17 18+19 20 21+22 23 24+25 26 27+28 29 30+31 ** 1+2 3 4 5+6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21

1+2 3 4 5+6 7 8 9 10 + 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 1 +2 3 4 5+6 7 8 9+ 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 1+2 3 4 5+6 7 8 9+ 10 11 12 13 14 15 16+17 18 19 20 21 22 23 24+25 26 27 28 29 30 31 32 33+34 * 1+2 3 4 5+6 7 8+9 10 11 12 13 14 15 16

1+2 3 4 5+6 7 8+9 10 11 12 13 14 15+16 17 18 19

1+2 3 4 5+6 7 8+9 10 11 12 13 14+15 16 17 18+19 20 *

1+2 3 4 5+6 7 8+9 10 11 12 13+14 15 16 17+18 19 *

1+2 3 4 5+6 7 8+9 10 11 12 +13 14 15+16 17 18+19 20 21+22 23 24+25 26 27+28 29 ** 1+2 3 4 5+6 7 8+ 9 10 11 + 12 13 14 15 16

1+2 3 4 5+6 7+ 8 9 10 + 11 12 13 14+15 16 **

1+2 3 4 5+6 7+ 8 9 10 + 11 12 13 +14 15 16+17 18 19+20 21 **

1+2 3 4+ 5 6 7+8

TABLE 9. Ptilocrinus (Chambersaecrinus) brucei. Main morphological variables in USNM specimens and type series. Wb: Br 1 width; Wr-b: radial aboral width; Wr-t: radial adoral width; Hc: aboral cup height; Hr-r: radial axial height; Hri: radial side height; Htg-a: tegmen height at anus; Htg-b: tegmen height at mouth; Dc: adoral diameter of aboral cup; Drb: diameter at radial-basal sutures; Dp: proximalmost stalk diameter; Dm: minimum stalk diameter in mesistele. Values in mm. Dp and Dm are used as growth index (in yellow).

Specimen Wb Wrb Wrt Hc Hrr Hri Htga Htgo Dc Drb Dp Dm
1005433-B 2.1 1.9 3.7 7.45 3.8 4.5 - - 6.2 3.4 1.9 1.4
paratype 3.4 - 6.7 11.55 6.6 6.75 - - - - ~2.5 1.95
1005453-A 3.4 3.75 5.6 12.6 6.6 7.5 - - - 6.25 2.75 -
1005433-A 4.1 4.7 4.1 6.3 6.8 16.15 15.2 8.8 10.5 >9.0 5.7 11.7 11.85 7.15 2.8 2.4
1005439 4.05 4.35 7.45 15.05 7.85 9.05 16.5 9.8 13.7 7.85 3.4 2.8
holotype 4.8 4.4 8.0 13.6 8.4 9.4 12.0 ~6.0 14.0 7.4 3.5 <3.0
1005438 5.5 - 8.9 - 9.25 12.0 - - - - >4.2 3.8

TABLE 10. Ptilocrinus (Chambersaecrinus) brucei. Variation of main morphological ratios in USNM specimens and type series. Abbreviations and growth index as in Table 9.

Specimen Hc/Dc Hr/Hc Htg/Hc Hr/Wr Wr/ Wb Dc/Dp Dc/Drb Drb/Dp Dp/Dm Dp
1005433-B 1.20 0.60 - 1.21 1.73 3.25 1.81 1.80 1.40 1.9
paratype - - - 1.01 1.97 - - - ~1.28 ~2.5
1005453-A - 0.60 - 1.34 1.69 - - 2.13 - 2.75
1005433-A 1.3-1.36 0.65 0.38 1.54-.65 1.45-.55 4.2-4.27 1.64-.66 2.57 1.17 2.8
1005439 1.1-1.12 0.60 0.65 1.21 1.83 3.97-4.06 1.71-.75 2.32 1.20 3.4
holotype 0.97 0.69 0.88 1.17 1.67 4.0 1.89 2.11 ~1.40 3.5
1005438 - - - - >1.32 - - - >1.11 >4.2

TABLE 11. Ptilocrinus (Chambersaecrinus) brucei USNM 1005438. Quantitative characters of proximal brachials.

Brachial rank Br1 Br2 Br3 Br4 Br5 Br6 Br7 Br8
Upper width (W) 5.2 5.3 4.1 3.6 3.6 3.6 3.5 3.5
Maxi height (H) 4.6 4.0 1.7 1.4 1.3 1.4 1.4 1.3
H/W 0.88 0.75 0.41 0.39 0.36 0.39 0.40 0.37

TABLE 12. Ptilocrinus (Chambersaecrinus) brucei USNM 1005438. Quantitative characters of columnals. Columnals numbered from proximal to distal. Dal: axial lumen diameter, Dcol: columnal diameter, Hcol: maximum columnal height. Values in mm, except ratios.

From cup base ~0 15 40 60 100 150 200 250 300 350 386
Diameter (Dcol) 4.15 4.0 3.9 3.85 3.75 4.1 4.1 3.9 4.1 4.6 5.95
Height (Hcol) <07 <07 1.0 1.5 1.4 1.3 1.7 1.6 1.4 1.4 1.1
Hcol/Dcol <0.2 <0.2 0.34 0.39 0.37 0.32 0.415 0.41 0.34 0.30 0.19
Dal/Dcol - 0.45 - 0.45 - - 0.31 - 0.25 0.14 0.09

TABLE 13. Ptilocrinus (Chambersaecrinus) brucei USNM 1005433 - B. Quantitative characters of columnals. Columnals numbered from proximal to distal. D: maximum columnal diameter, H: columnal height. Values in mm, except H / D.

From cup base 0 5 20 35 50 89.5
Diameter (D) 1.9 1.5 1.4 1.4 1.4 1.55
Height (H) <0.4 <0.4 0.8 1.9 2.0 1.85
H/D 0.18 0.22 0.56 1.36 1.43 1.19

TABLE 14. Ptilocrinus (Chambersaecrinus) brucei, R / V Dmitri Mendeleev sta. 4094. Stalk measurements. D: maximum columnal diameter, H: columnal height. Values in mm, except H / D.

Stalk fragment Mid-distal mesistele Proximal dististele Distal dististele
From proximal 0 83.2 0 31 0 49
Diameter (D) 2.2 2.3 2.6 2.7 2.8 3.2
Height (H) 1.1 1.1 1.1 1.2 1.1 0.7
H/D 0.5 0.48 0.42 0.44 0.39 0.22
NMS

National Museum of Scotland - Natural Sciences

USNM

Smithsonian Institution, National Museum of Natural History

Kingdom

Animalia

Phylum

Echinodermata

Class

Crinoidea

Order

Hyocrinida

Family

Hyocrinidae

Genus

Ptilocrinus

SubGenus

Chambersaecrinus

Kingdom

Animalia

Phylum

Echinodermata

Class

Crinoidea

Order

Hyocrinida

Family

Hyocrinidae

Genus

Ptilocrinus

SubGenus

Chambersaecrinus

Loc

Ptilocrinus (Chambersaecrinus) brucei Vaney

Roux, Michel 2015
2015
Loc

P. (Chambersaecrinus) flexibilis

Mironov 1998: 55
1998
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