Porphyrocrinus daniellalevyae, Messing, Charles G., 2016

Messing, Charles G., 2016, Porphyrocrinus daniellalevyae n. sp. (Echinodermata: Crinoidea), a sea lily from the tropical western Atlantic with a unique crown pattern, Zootaxa 4147 (1), pp. 1-35 : 3-8

publication ID	https://doi.org/ 10.11646/zootaxa.4147.1.1
publication LSID	lsid:zoobank.org:pub:DFDC5EE6-BB16-4BDD-883D-3530AAD04FA0
DOI	https://doi.org/10.5281/zenodo.6069868
persistent identifier	https://treatment.plazi.org/id/03A6C633-C84B-4501-CAE9-FA8F751DF80C
treatment provided by	Plazi
scientific name	Porphyrocrinus daniellalevyae
status	sp. nov.

Treatment

Porphyrocrinus daniellalevyae View in CoL new species

Etymology. Porphyrocrinus daniellalevyae n. sp. is named in honor of Daniella Levy Becker by Robert Becker in recognition of their generous support for research on crinoids at Nova Southeastern University.

Material. USNM 1411123 About USNM (holotype) Johnson Sea-Link II 3698, West of Little Bahama Bank , 27º04.0652'N, 79º19.2923'W, 582 m, 29 July 2009 GoogleMaps . USNM 1411124 About USNM (large paratype) and MNHN-IE-2014-2001 (small paratype) (both partly dissociated for SEM), Johnson Sea-Link II 3685, West of Little Bahama Bank , 27º04.499’N, 79º19.200’W, 616 m, 23 July 2009 GoogleMaps . UMML 44.239 View Materials (paratype, crown only), R/ V Suncoaster, dredge #3, S of Bimini, Bahamas, 25º28.477’N, 79º17.632’W, 400 m, 23 May 2002, A. Oleinik, coll. GoogleMaps

Diagnosis. A species of Porphyrocrinus with at least eight and up to at least 17 radials, the number probably increasing with size. Stalk to at least 408 mm long; proxistele of 7–11 thin, disk-like columnals; no articulations with multiradial facets; dististele short (11 columnals in single specimen with complete stalk); ratio of major to minor columnal diameter (D/d) to 1.4 distally. Aboral cup as wide distally as tall (small specimen) to wider than tall; basals squarish or taller than wide; radials taller than wide. Rays unbranched; arms to at least 73 mm long, with distal apinnulate filament; maximum arm width at Br4–6; proximal arm articulation pattern chiefly 1+2 3+4 5+6 with first pinnule on left side of Br6 but with several variations. First 4–5 pinnules on both sides of arm genital; gonadal expansion covered with thin interlocking plates; ambulacral tissue of middle and distal pinnules with numerous small fine single and irregularly branched needles, and few small coarse meshes. Disk interambulacral areas at least partly covered with thin, polygonal interlocking plates.

Description of holotype ( Figures 1 View FIGURE 1 A–C, 2, 3A–B, 4A, 5, 6B-C; Tables 1, 2). Total stalk L= 408 mm including attachment disk, of 124 columnals; attachment disk thick and truncated ( Figure 2 View FIGURE 2 ). Proxistele of proximalmost 11 visible columnals with tight sutures difficult to distinguish ( Figure 4 View FIGURE 4 A). Mesistele (C12–C113) accounting for great majority of stalk length; weak synarthrial gap visible externally between C11–12, but D/d>1.0 at C13–14 (1.02, 1.08); pairs of columnals developing barrel-shaped profile across major diameter (D) by C14–15. Mesisteledististele transition at C113–114, corresponding to increase in D from 4.3 mm (C111) to 4.5 mm (C114).

Stalk diameter (D) (Table 1): C1 same as base of adjacent basal ring; gradually decreasing to C13–14; increasing gradually from C15 to 3.8 mm by mid-stalk, and 5.5 mm immediately above attachment disk ( Figure 3 View FIGURE 3 A). Columnal height: C1–7 thin, discoidal, 0.2–0.3 mm tall; gradually increasing in height to C81 (4.5 mm), remaining about the same to C100, and diminishing irregularly to just above base (2.6 mm). Columnal HD ratio: similar for C1–6 (0.11–0.14), gradually increasing and reaching 1.0 by C32; remaining similar from ~C53 to C92 (1.07–1.15), then gradually decreasing, especially following C108 (0.90), through mesistele-dististele transition (0.85), to 0.69 (C120) and 0.50 (C123) (omitting abnormal C121 and 124) ( Figure 3 View FIGURE 3 B). Slight dip in HD ratios ( Figure 3 View FIGURE 3 B, large arrow) due to slight but abrupt increase in columnal diameter from 1.8 (C17) to 2.3 (C21) with little increase in ossicle height.

C112 and 113 each shorter and narrower than C111 or C114, joined by tightly anchylosed articulation ( Figure 2 View FIGURE 2 , upper arrow); C121 longer and narrower than C120 or C122 ( Figure 2 View FIGURE 2 , lower arrow; 3A and B, small arrows), with slightly constricted, apparently rudimentary anchylosis (i.e., possibly two ossicles) (see under USNM 1411124 for descriptions of facets of articulations with similar exterior appearance); distalmost columnal (C124) above attachment disk much shorter and narrower than those above it.

Aboral cup (basal+radial rings) wider adorally than tall. Basal ring almost cylindrical; diameter slightly greater adorally; sutures indistinct ( Figure 4 View FIGURE 4 A). Radial ring a short, inverted, truncated cone of 15 radials. Profiles of radial and basal rings creating an angle of 140–150º. Individual radial ossicles straight sided, slightly wider distally; aboral surface gently convex. Radials shorter than basals.

Rays 73 mm long, including remaining ~17-mm apinnulate terminal filament ( Figure 1 View FIGURE 1 C). IBr1 squarish, laterally apposed, slightly wider distally; joined to radial by muscular synarthry. IBr2 similar but wider, with weak thin lateral flange; WH 1.2–1.3. IBr3 to IBr6–8 gradually wider and shorter with more strongly developed flange; WH increasing from 1.5 to 1.8. Following brachials more strongly rounded, with plane of thin lateral margins oriented toward interior of crown. Middle brachials shorter, wider distally, with distal margin slightly raised; free middle brachials becoming squarish through middle of arm; proximal ossicle of a brachial pair higher, with convex distal margin and WH 1.9; distal brachial of a pair shorter, with straight distal margin and WH 1.4. Distal brachials narrower with slightly expanded distal ends, becoming higher than wide, but no higher than shorter middle brachials; WH 0.8–0.9. Arms terminating in delicate threadlike filament up to 30 mm long (none remaining complete) ( Figures 1 View FIGURE 1 B, C). Aboral and lateral surfaces of brachials covered with crowded, distally-directed recumbent spines; spines becoming more erect but still distally-directed on distal brachials (see Figures 15 View FIGURE 15 E–F, 17B–C, E, 21C for the same features on USNM 1411124 and MNHN-IE-2014-2001). Table 2 indicates pattern of proximal articulations; all ligamentary articulations appear to be trifascial synarthries (see USNM 1411124 below for descriptions); one or two brachials of a triplet often shorter than others; pattern from IBr6 or 8 to IBr20–25 chiefly brachial pairs alternating with single free brachial; few successive pairs or two successive free brachials also present. Brachial pairs commonly separated by two free brachials beyond ~IBr30 with some series of 3–4 successive free brachials distally (beyond IBr50) (on detached arms). Plane of trifascial articulations distal to IBr6 tilted with respect to arm axis in lateral view, so that aboral face of distal ossicle of a pair is shorter (arrows in Figure 5 View FIGURE 5 ).

On remaining attached rays (2 now broken near bases), first pinnule on left side of IBr5+6 (2 cases), IBr6+7 (9 cases), IBr5+6+7 (3 cases) and on right side of IBr7+8 (1 case) (in aboral view with arm base down as in Figures 2 View FIGURE 2 , 9 View FIGURE 9 B) ( Table 2). Proximal two pinnulars of all pinnules short, ~ 0.3 mm high. First 4–5 pinnules on each side genital, 4.5 mm long, of 11 segments. Well-developed gonadal inflation extending from pinnular 4 to 8–10 ( Figure 6 View FIGURE 6 A); distalmost gonad smaller than others, extending along 3–4 pinnulars. First pinnular of genital pinnule with HW 1.3, second 1.0; following pinnulars becoming slender with expanded ends and HW>4.0; distal few pinnulars shorter. Pinnulars of gonadal inflation with thin lateral expansion. Gonads covered with thin, irregular, interlocking plates ( Figure 6 View FIGURE 6 A). Middle pinnules to 7 mm long with up to 19 pinnulars and HW to 8.0. Distal pinnules threadlike, to 10 mm long, of up to 22 pinnulars with HW of individual pinnulars up to 10.0. First pinnular of middle and distal pinnules with HW ~1.0, and with thin, distally-pointed, blade-like flange on lateral margin facing base of arm (see under Figure 17 View FIGURE 17 F USNM 1411124 below). Ambulacral tissue of middle and distal pinnules containing numerous small fine single and irregularly branched needles, and few small coarse meshes ( Figure 6 View FIGURE 6 B, C).

Disk (partly visible between two broken arms) flat, reaching level of IBr8, connected to arms by short narrow bridges that reach IBr9; interambulacral areas at least partly covered with extremely thin, polygonal interlocking plates.

Description of USNM 1411124 ( Figures 3 View FIGURE 3 B–C, 4C, 7–18, Tables 1–2) (partly dissociated for SEM). Remaining stalk L= 398 mm, of 101 externally visible columnals (the distalmost broken); detached close to attachment disk ( Figure 7 View FIGURE 7 ). Proxistele of 7 visible columnals (C1–7) similar to holotype; weak synarthrial articulation visible externally between C7 and C8; C7 with D/d 1.03; end of fulcral ridge evident externally by C9– 10; pairs of columnals developing barrel-shaped profile by C15–16. No dististele retained; D and HD decreasing gradually from C84 to remaining distal end ( Figure 3 View FIGURE 3 C, D); D/d ~1.4 from mid-stalk to remaining end. Two pairs of columnals (C30+31, C87+88) tightly anchylosed; articulation appearing exteriorly as synostosis with no trace of syzygial pattern (see description of facets of similar-appearing articulations for USNM -IE-2014-2001 below).