taxonID	type	description	language	source
6BADD7681834548E95A9595588D4AF23.taxon	type_taxon	Type species. Pentacrinus maclearanus Thomson, 1872.	en	Sun, Shao’e, Mei, Zijie, Sha, Zhongli (2025): Endoxocrinus (Diplocrinus) kexuei, a new species of stalked crinoid (Echinodermata, Crinoidea, Isocrinida, Balanocrinidae) from rotten wood in the cold seep area of the Taixinan Basin, South China Sea. ZooKeys 1241: 185-204, DOI: 10.3897/zookeys.1241.128991
BEF603F28B9654C4B7C6CC6AE6C89226.taxon	description	Figs 1, 2, 3, 4, 5, 6, 7, 8, 9	en	Sun, Shao’e, Mei, Zijie, Sha, Zhongli (2025): Endoxocrinus (Diplocrinus) kexuei, a new species of stalked crinoid (Echinodermata, Crinoidea, Isocrinida, Balanocrinidae) from rotten wood in the cold seep area of the Taixinan Basin, South China Sea. ZooKeys 1241: 185-204, DOI: 10.3897/zookeys.1241.128991
BEF603F28B9654C4B7C6CC6AE6C89226.taxon	diagnosis	Diagnosis. Arm number 20 – 22; arms smooth, up to 14 cm long; lateral flanges present on all proximal brachials; IB r 1 + 2 synostosis very flat with synostosial stereom predominating; axial canal rectangular; stalk shorter than arms, 6.5 cm long; internodals per mature noditaxis 5 – 8; stalk stellate to pentagonal cross-section; proximalmost diameter of stalk 5 mm; less than five (down to 2) cirri per nodal; proximal cirri directed upward; cirrus sockets large and round; 30 robust cirrals per cirrus; cirri rudimentary until 3 th nodal; cryptosymplexies without marked symmorphy and with facets mainly covered by synostosial stereom axial canal usually incompletely filled with stereom needlelike network and preserving an irregular secondary lumen	en	Sun, Shao’e, Mei, Zijie, Sha, Zhongli (2025): Endoxocrinus (Diplocrinus) kexuei, a new species of stalked crinoid (Echinodermata, Crinoidea, Isocrinida, Balanocrinidae) from rotten wood in the cold seep area of the Taixinan Basin, South China Sea. ZooKeys 1241: 185-204, DOI: 10.3897/zookeys.1241.128991
BEF603F28B9654C4B7C6CC6AE6C89226.taxon	etymology	Etymology. The species name is derived from the oceanographic vessel “ Kexue ” of the Institute of Oceanology, Chinese Academy of Sciences, which made a significant contribution to the biological research in the South China Sea.	en	Sun, Shao’e, Mei, Zijie, Sha, Zhongli (2025): Endoxocrinus (Diplocrinus) kexuei, a new species of stalked crinoid (Echinodermata, Crinoidea, Isocrinida, Balanocrinidae) from rotten wood in the cold seep area of the Taixinan Basin, South China Sea. ZooKeys 1241: 185-204, DOI: 10.3897/zookeys.1241.128991
BEF603F28B9654C4B7C6CC6AE6C89226.taxon	description	Description. Morphological description of the holotype. Specimen MBM 287584 (Figs 1 – 6). Colour (Fig. 1 a, b) pale yellow-pink in fresh samples, and white after alcohol immersion. Several arms and all cirri broken. Arms 22, surface smooth, whole arm length 8 – 17 cm; two or three divisions per ray, two of these rays have three divisions, rays closely aligned (Fig. 2 a); all brachitaxes of two ossicles, united by non-muscular joints (synostosis). On all free arms, the first two brachials are connected by a synostosis muscular articulations present on the remaining branchials. IB r 1 rectangular with distal lateral margins weakly everted. IB r 2 pentagonal with lateral margin somewhat thickened and crenulated. IIB r 1 + 2 and IIIB r 1 + 2 with lateral flanges. IIB r 1 and IIIB r 1 with exterior lateral margin longer than interior. Proximal brachials (up tp B r 6) approximately square, with varying degrees of crenulate on lateral margin, the edge regular, flat and close to straight, giving a very angular appearance to the brachials. The non-functional ligamentary articulations IB r 1 + 2, IIB r 1 + 2 and IIIB r 1 + 2, are clearly identified as synostosis. The synostosis of IB r 1 + 2 very flat with synostosial stereom predominating and rectangular axial canal (Fig. 5 a, b). However, at IIB r 1 + 2 and IIIB r 1 + 2 (Fig. 5 c – f), while synostosial stereom predominats and, syzygial stereom forms rudimentary crenularium near the aboral edge of the facet; the syzygial stereom remains very irregular on the lateral edges. On the free arms, non-muscular junctions are present only in B r 1 + 2, whose general morphological features are similar to the secundibrachial or tertibrachials synostosis, with synostosial stereom forming a rudimentary crenularium on the aboral margin of the articular facet (Fig. 6 a, b). The rest of the brachial articulations are typical isocrinid synarthries (Fig. 6 c, d). Basals form quadrilateral projections, protruding and separated from each other (W / L = 1.4 – 1.6). Radials hexagonal or pentagon, laterally adjacent (W / L = 2.4 – 2.8). First pinnule (P 1) on B r 2 (Fig. 3 a), with 9 – 11 pinnulars, approximately 8.1 mm long; second pinnular longest, up to 1.4 mm, penultimate segment slender, twice as long as wide. P 2 to P 4 short and wide; proximal segments relatively long, middle segments longest, and distal segments abruptly narrowed and shortened. P 10 to P 15 longest and slender, about 13.5 – 16.5 mm long, with 17 – 19 pinnulars; proximal segment wider, middle segments longer than wide (L / W = 1.4 – 1.6); distal pinnulars with small spines on dorsal edges. Pinnules gradually becoming shorter towards the distal of the arm. P 20 to P 29 composed of 6 – 15 segments, pinnulars longer than wide (L / W = 1.6 – 2.0), except the first pinnular. Stout stalk about 7.8 cm long and counts 39 whole columnals, distal nodal slightly broken proximal stalk gradually turning from star-shaped to pentagonal in cross-section, 5 mm in diameter proximally and 4.3 mm distally, the longest noditaxis is the seventh (6.92 mm) with eight nodals, proximal nodals are 1.2 mm in height and distal ones being 2.1 mm tall in this noditaxis; less than 5 cirri on each nodal, usually two or three, four on the 6 th nodal and two on the 7 th nodal. Proximal cirri directed upward, forming an acute angle with the proximal stalk; rudimentary cirri on the first to third nodal. The number of interrnodal per noditaxis is 5 (Fig. 2 b). Between two nodals, the internodal exactly in the middle is slightly higher than the others. Cirri remaining rudimentary, usually before the 3 th nodal. Fully developed cirrus slender with 30 cirrals, 6.3 – 8.5 cm long (Fig. 2 c) (others incomplete or missing); cirrus sockets large and round, occupying approximately the entire height of nodal (Fig. 2 b). The first 3 segments are relatively short. c 1 – c 4 with W / L = 1.7 – 2.3; c 5 to c 9 longest, longest cirral with W / L = 0.8 – 1; subsequent cirrals gradually shorter, c 13 – c 15 with W / L = 1.0 – 1.1; terminal claw quite small, slightly longer than the penultimate segment, no opposing spine; distalmost three cirri curved downward for fixation. Nodal and infranodal united by cryptosymplexy. The cryptosymplexy (Fig. 4 a) is pentalobate and flat, with synostosial stereom occupying most of it and syzygial stereom restricted to its outer margin. The round axial canal (Fig. 4 b) is partially filled with a relatively long spicule network separated from the perilumen and preserving an irregular secondary lumen. Petaloid zones (Fig. 4 c) pear-shaped, interpetaloid zone is dominated by syzygial stereom and without axial groove. Symplexies present between internodals (Fig. 4 d), each petaloid zone having 6 – 8 crenulae and open lanceolate areola and interpetaloid zone (Fig. 4 e) is dominated by labyrinthic stereom. Morphological description of the paratype. Specimen MBM 287585 (Figs 7 – 9) incomplete, part of the stalk and all cirri are missing (Fig. 6 b). Paratype is similar to the holotype, yet smaller. Differences are listed below. 20 smooth arms, up to 7 – 8 cm long. Two brachials per brachitaxes and two divisions per ray. IB r 1 + 2 ax and IIB r 1 + 2 ax (Fig. 8 a). Proximal branchials with lateral edges less waved than in the holotype. Branchial surface smooth. IB r 1 + 2, IIB r 1 + 2 and IIIB r 1 + 2, have small lateral flanges. Basals rhombic, prominent and obviously apart from each other, W / L = 1.1 – 1.5. Radials hexagonal or pentagon, W / L = 1.9 – 2.3. P 1 on B r 2 (Fig. 8 b), with 8 – 9 pinnulars. Oral pinnule short; proximal pinnulars thick and wide, distal pinnulars become slender and longer. Middle pinnule longest, with 11 – 13 pinnulars, 13.0 mm long. At the end of arms, pinnule shorter or absent. The remaining stalk length is about 1.7 cm, proximal column cross-section stellate to pentagonal. Proximal infranodal columnal facet (Fig. 9 a) with slight symmorphy in inner part, pear-shaped petaloid zones, and axial canal completely filled with dense thin stereom network without secondary lumen (Fig. 9 c). Cryptosymplexies (Fig. 9 b) relatively flat without marked symmorphy and with facets mainly covered by synostosial stereom. Outer margin zone and interpetaloid zone with syzygial stereom predominating. Axial canal (Fig. 9 d) markedly pentagonal and partially filled with a relatively long spicule network separated from the perilumen and preserving an irregular secondary lumen. Quantitative morphological characters are reported in Table 1.	en	Sun, Shao’e, Mei, Zijie, Sha, Zhongli (2025): Endoxocrinus (Diplocrinus) kexuei, a new species of stalked crinoid (Echinodermata, Crinoidea, Isocrinida, Balanocrinidae) from rotten wood in the cold seep area of the Taixinan Basin, South China Sea. ZooKeys 1241: 185-204, DOI: 10.3897/zookeys.1241.128991
BEF603F28B9654C4B7C6CC6AE6C89226.taxon	distribution	Distribution. Only known from the cold seep in the Taixinan Basin, South China Sea, at a depth of 833.7 m.	en	Sun, Shao’e, Mei, Zijie, Sha, Zhongli (2025): Endoxocrinus (Diplocrinus) kexuei, a new species of stalked crinoid (Echinodermata, Crinoidea, Isocrinida, Balanocrinidae) from rotten wood in the cold seep area of the Taixinan Basin, South China Sea. ZooKeys 1241: 185-204, DOI: 10.3897/zookeys.1241.128991
