DENDROCRINIDAE Wachsmuth & Springer, 1886

Ausich, William I. & Göncüoglu, M. Cemal, 2020, Juvenile eucladid crinoid from the Middle Devonian of Turkey, Geodiversitas 42 (14), pp. 215-221 : 218

Class CRINOIDEA Miller, 1821 Parvclass CLADIDA Moore & Laudon, 1943 Magnorder EUCLADIDA Wright, 2017 Family DENDROCRINIDAE Wachsmuth & Springer, 1886

Genus and species indet.

MATERIAL. — METU-Geol Mus 2018-P1.

LOCALITY. — South of Geraşin glacial lake, Karadağ Mountain to the NE of Cevizli Village, Çukurca, Hakkari, southeastern Turkey (37°21’56.64’’N, 43°47’45.14’’E).

HORIZON AND AGE. — Yığınlı Formation, lower part of Member 5; Late Devonian (Famennian).

MEASUREMENTS (in mm; *, indicates an incomplete measurement or a crushed specimen). — CrH, 10.7; ACH, 2.14; ACpW, 0.3; ACdW, 2.9*; ICH, 0.42; BH, 0.64; BW, 0.57; RH, 0.79; RW, 0.86; AH, 9.7; ASH, 8.4; CoH, 7.1.

DESCRIPTION AND COMPARISON

Very small crown, conical ( Fig. 3 ). Aboral cup medium cone shaped, width to height ratio approximately 1.3 (with cup compacted), plates gently convex, surface texture of plates not preserved.

Infrabasal circlet approximately 23% of aboral cup height, base truncate; individual infrabasal plates not defined. Basal circlet approximately 35% of aboral cup height; non-CD interray basal plates, hexagonal, approximately as high as wide, smaller than radials. Radial circlet approximately 42% of aboral cup height; as known radial plates pentagonal, approximately 1.1 times wider than as high ( Fig. 4 ). Radial facets probably peneplenary, planate.

Anal plates unknown. Central portion of preserved crown characterized by many, poorly defined, irregularly shaped small polygons that may represent the anal sac. This structure is nearly as high as the arms, tapers distally to a rounded shape.

Arms branch once, as known, in what appears to be an isotomous division. All brachials higher than wide or much higher than wide, 4 or more primibrachials. All brachials rectangular uniserial, aborally convex ( Fig. 4 ).

Column circular, heteromorphic, holomeric; proxistele columnals wider than high; latus convex; mesistele columnals more equidimensional with straight latus ( Fig. 3 ); other details of column unknown.

Figures

FIG. 3. — Photograph of Dendrocrinidae? gen., sp. indeterminate. Specimen coated with ammonium chloride. Scale bar: 1.0 mm.

FIG. 4. — Plate diagram of Dendrocrinidae? gen.,sp.indet.Black, radial plates; grey, matrix; Scale bar: 1.0 mm.