Pentamera fonsecae Solis-Marin & Alvarado & Conejeros-Vargas & Caballero-Ochoa 2020, n. sp.
Creators: name: Solis-Marin, Francisco Alonso
name: Alvarado, Juan Jose
name: Conejeros-Vargas, Carlos Andres
name: Caballero-Ochoa, Andrea Alejandra
Publisher: name: Zenodo
Year: 2020
Subjects: Biodiversity
Taxonomy
Animalia
Echinodermata
Holothuroidea
Dendrochirotida
Phyllophoridae
Pentamera
Pentamera fonsecae

description: Pentamera fonsecae n. sp.
Figs. 1–4
Type material. Holotype: MZUCR 755. RV Urracá-STRI Expedition, Station 17, Bahía Naranjo, Golfo de Papagayo, off rocky area, Guanacaste Province, Costa Rica, Pacific Ocean, (10° 45.936’ N, 85° 39.845’ W), 28.5–40 m, muddy bottom, Coll. July 15 th, 2005, C. Fernández and R. Vargas. Paratypes: ICML-UNAM 18348 (two specimens), MZUCR 756 (four specimens), all from the same locality as the holotype. SEM stubs are kept together with the holotype.
Type locality. Urracá Expedition, Station 17, Bahía Naranjo, Golfo de Papagayo, off rocky area, Guanacaste Province, Costa Rica, Pacific Ocean, (10° 45.936’ N, 85° 39.845’ W), 28.5–40 m depth.
Diagnosis. Body U-shape, reaching up to 57 mm, anterior and posterior ends slightly up-turned; skin usually stiff and brown. Skin thin, smooth. Tube feet only in the radii, nonretractile, in five series, longer and more abundant in midventral region than distally. Ten small dendritic tentacles including smaller ventral pair. Calcareous ring long and tubular, with forked posterior processes on the radials, made up of a mosaic of smaller pieces; ratio of radial to interradial length approximately 4:1. Body wall ossicles are tables with ladder-shaped spire (100–300 μm) covering about 4–5 times width of the disk, sometimes with a distinct cross-beam at the opposite side of the spire. Tube feet with curved support tables (100–110 μm) of variable height and tables with ladder-shaped spire slightly smaller than those from the body wall. Tentacle ossicles in three forms, rosettes, finer curved oval plates and large robust rods with a few holes. Introvert with perforated rods, large tables with low spire and few rosettes.
Etymology. We take great pleasure in naming this species after Dr.Ana Cecilia Fonseca Escalante (1970–2013) foremost reef ecology researcher of Costa Rica and Central America, a scientist at the Centro de Investigación en Ciencias del Mar y Limnología (CIMAR), of the Universidad de Costa Rica. She was a woman passionate about marine life and a defender of the coral reef health for which she fought until her last days.
Description of holotype. Specimen (female) slender, slightly curved, length along the body 57 mm and breadth in mid-body 13 mm (Fig. 1A). Preserved coloration brown, tube feet and tentacles light brown to white. Mouth terminal; anus terminal with five small papillae and five delicate anal teeth. Tentacles contracted, ten in number, well-branched, largest about 2–3 mm long, two ventral ones smaller. Tube feet restricted to radii, in staggered rows, longer in the ventral radii, shorter dorsally. Interambulacra naked, without papillae, warts or tubercles. Skin smooth, with numerous small ossicles. Introvert thin, short, without tube feet. Calcareous ring with posterior processes elongated and fragmented (Figs. 1B, C). Radial plates longer than interradial, approximately 6 mm high and 1 mm wide, anterior part bifid, posterior processes with small pieces; interradial plates triangular anteriorly, with posterior margin convex, 2 mm high and 0.8 mm wide. Polian vesicle single, thin, and elongated, located left of ventral mesentery; stone canal thin, straight, elongated; madreporite well calcified, bean-shaped (Fig. 1B). Gonads in two tufts, each located one tuft on each side of dorsal mesentery where it joins the dorsal body wall; each gonad composed by several tubules attached anteriorly, unbranched, forming several saccules along the tubule, filling the entire body cavity, full of eggs in various stages of development. Longitudinal muscles thin; retractors also thin, more delicate. Respiratory trees confined to posterior quarter of body, with very short branches. Characteristic ossicles of body wall as tables with ladder-shaped spire with an irregular disk (Figs. 2A, 3A), 100–300 μm high and 20–25 μm wide, ending in a rounded tip; sometimes there is a characteristic cross-beam at the opposite side of the spire. Tube feet with supporting tables with curved disk with four central holes and one hole at each end, disk 90–110 μm long and spire 20–40 μm high (Figs. 2B, 3B) and rounded endplates about 80–100 μm in diameter. Introvert with tables with two pillared low spires and big perforated rods (Fig. 2C) and a few rosettes (Fig. 2E 1). Tentacles with rods of vari-ous sizes, some delicate, with perforations at each end, some curved; irregular perforated plates, oblong, straight to slightly curved, medial perforations larger (Fig. 2D) and rosettes similar to those of introvert (Fig. 2E2). Gonads with fragile double pillared tables (Fig. 4A). Disks elongated, often irregular in outline, with four large holes around small central hole and from three to four peripheral ones; usually 110–120 μm wide (Fig. 4B). Spire high, slender (60–65 μm) or short (30–35 μm) and stout; pillars of two types: double pillar at the base of the table, becoming a single pillar upward, sometimes with short lateral ramifications; double pillar that joins into a single pillar upwards, sometimes with 4-9 transversal beams, ending in a flat tip. Occasional a cross-beam on the opposite side of the spire is presented (Fig. 4A). Respiratory trees, longitudinal muscles, intestine and cloaca devoid of ossicles.
Description of paratypes. The paratypes are from 40 to 44 mm long. The ossicles of the body wall, tube feet, introvert, and tentacles are very similar to those of the holotype. The body color varies from light to dark brown. Some specimens have dark brown body and light brown tube feet.
Distribution and habitat. Pentamera fonsecae n. sp. has been only recorded from the Guanacaste Province, Costa Rican Pacific. It occurs in muddy substrata, between 28.5 and 40 m depth.
Remarks. Pentamera fonsecae n. sp. is similar to P. zacae Deichmann, 1938 in the shape of the table ossicles. P. zacae has a narrow and shorter spire described as “acorn-shaped” by Deichmann (1941). We present here a new ossicle shape defined as table with a “ladder-shaped” spire present in this new species. Pentamera fonsecae n. sp. shares its geographic distribution in the Costa Rican Pacific with P. chierchiae (Ludwig, 1887) and P. beebei Deichmann, 1938. It differs from the former in lacking the four-holed tables with dentate margin present in the body wall; P. fonsecae n. sp. is similar to P. beebei in having support tables with a tall spire present in the tube feet, but those in P. beebei are taller (55–70 μm) and the ones in P. fonsecae n. sp. are much shorter (30–50 μm).
Pentamera fonsecae n. sp. is clearly distinguished from all other species of the genus in having tables with a ladder-shaped spire in the body wall.
description: Published as part of Solis-Marin, Francisco Alonso, Alvarado, Juan Jose, Conejeros-Vargas, Carlos Andres & Caballero-Ochoa, Andrea Alejandra, 2020, Pentamera fonsecae n. sp. a new species of sea cucumber from the Pacific coast of Costa Rica (Holothuroidea: Dendrochirotida: Thyonidae), pp. 581-588 in Zootaxa 4878 (3) on pages 583-586, DOI: 10.11646/zootaxa.4878.3.9, http://zenodo.org/record/4425512