Hemipholis cordifera
Creators: name: Alitto, Renata A. S.
name: Bueno, Maristela L.
name: Guilherme, Pablo D. B.
name: Domenico, Maikon Di
name: Christensen, Ana Beardsley
name: Borges, Michela
Publisher: name: Zenodo
Year: 2018
Subjects: Biodiversity
Taxonomy
Animalia
Echinodermata
Ophiuroidea
Ophiurida
Ophiactidae
Hemipholis
Hemipholis cordifera

description: Hemipholis cordifera (Bosc, 1802)
(Fig. 16)
Type locality. South Carolina, United States.
Maximum size. dd up to 12 mm (Tommasi 1970).
Material examined. 62 specimens (dd: 1.6–8.9 mm) from subtidal: ZUEC OPH 2106, St. 34, 1 spm; ZUEC OPH 2107, St. 32, 1 spm; ZUEC OPH 2109, St. 34, 1 spm; ZUEC OPH 2191, St. 71, 1 spm; ZUEC OPH 2195, St. VII, 2 spms; ZUEC OPH 2203, St. XXII, 1 spm; ZUEC OPH 2215, St. XXI, 1 spm; ZUEC OPH 2246, St. XIX, 1 spm; ZUEC OPH 2251, St. XIX, 1 spm; ZUEC OPH 2266, St. 145, 13 spms; ZUEC OPH 2271, St. XXVI, 20 spms; ZUEC OPH 2306, St. XIX, 1 spm; ZUEC OPH 2329, St. 9H, 3 spms; ZUEC OPH 2338, St. 20H, 2 spms; ZUEC OPH 2355, St. XXXIV, 13 spms.
Description. Disc: (dd: 6.2 mm) circular, covered by well-developed scales, approximately 18 between the central primary plate and the edge of the disc. Primary radial plates rounded and evident. Radial shields acute proximally, 1.5 times as long as wide, half-circle meeting at distal tips and separated by three scales. Two spines at the outer edge of the radial shields (Fig. 16A). Ventral interradius without scales (Fig. 16B). Oral shields oval, as long as wide, with a wide angle proximally. Madreporite larger than other oral shields. Adoral shields wider distally, touching both at inner apex of the oral shield and above the first ventral arm plate, establishing a continuous border encircling the oral aperture and jaws. One lateral oral papilla spiniform. One apical papilla, straight distally and convex proximally (Fig. 16C).
Arms: dorsal arm plates semi-circular to half-circle, twice as wide as long, straight proximally, rounded distally and contiguous (Fig. 16D,F). Ventral arm plates hexagonal, as long as wide and contiguous (Fig. 16E,G). One elongated tentacle scale, half-length of one ventral arm plate. Three slender pointed arm spines (Fig. 16E).
Lateral arm plates (Fig. 16H,I): general outline: ventral portion projecting ventro-proximalwards; ventro-distal tip not projecting ventralwards. Outer surface ornamentation: trabecular intersections protruding to form knobs larger than stereom pores on most of outer surface. Outer proximal edge: surface lined by discernible band of different stereom structure, restricted to central part; without spurs; central part protruding; surface without horizontal striations. Spine articulations: on same level as remaining outer surface, sizes all similar; distance between spine articulations increasing dorsalwards. Lobes simply separated, dorsal lobe clearly larger than the ventral lobe; lobes parallel, bent, and oriented nearly horizontal; stereom with perforations; sigmoidal fold absent. Inner side, ridges and knobs: clearly dominated by two separate central knobs; without additional dorsal structure on inner side; single large perforation on inner side.
Vertebrae: zygospondylous of universal type and keeled. Large groove on proximal side of vertebrae dorsally corresponding to distalwards projecting dorso-distal muscular fossae of distal side (Fig. 16J). Zygocondyles dorsalwards converging and zygosphene fused with pair of zygocondyles (Fig. 16K). Dorso-distal muscular fossae transformed distalwards clearly projecting beyond zygocondyles (true keel) (Fig. 16L). Zygosphene projecting beyond ventral edge of zygocondyles with projecting part shorter than zygocondyles (Fig. 16M).
Taxonomic comments. The vertebrae possess a dorsal distal keel, dorsal projections, and depressions connected by dorsal accessory muscles, which are also evident on the dorsal vertebral surface. The most recent taxonomic review conducted for H. cordifera (Bosc, 1802) and H. elongata (Say, 1825) by Hendler (2011) suggested synonymizing the two species as there are insufficient morphological features to keep them separate. H. elongata is considered nomen dubium. H. cordifera is similar to H. gracilis, except that H. gracilis has i) radial shields more constricted proximally, and ii) the basal ventral arm plates, particularly the second ventral arm plate, are relatively shorter and wider, and iii) the arm spines tend to be more tapered (Hendler 2011).
Remarks. Some specimens were collected near the sewage outfall from Basic Sanitation Company of the State of São Paulo (SABESP). This was not considered unusual as this species is known to tolerate poorly oxygenated sediments (Hendler et al. 1995; Christensen & Colacino 2000). As H. cordifera lacks bursae, its gas exchange and transport is achieved by circulation of the hemoglobin containing coelomocytes in its water vascular system (Beardsley & Colacino 1998). This mode of oxygen transport and its insensitivity to sulfides may allow H. cordifera to live in polluted environments (Christensen & Colacino 2000; Santos & Pires-Vanin 2004). This species is detritivorous (Borges & Amaral 2005), tolerates reduced salinities, low temperatures, and high turbidity (Sheridan & Badger 1981; Hendler 2011). H. cordifera may occur in high densities (Valentine 1991; Hendler et al. 1995), and is often found with the amphiurid Microphiopholis atra and the ophiactid Ophiactis lymani (Tommasi 1970). H. cordifera was collected in the present study with these species and with the amphiurids Amphiodia riisei, Amphipholis januarii, Amphiura kinbergi, Amphiura princeps and Microphiopholis subtilis. H. cordifera can be found on mud flats, oyster beds and sandy plains around coral reefs (Hendler et al. 1995; Alvarado & Solís-Marín 2013). It is often found associated with the polychaete Diopatra cuprea (Ruppert & Fox 1988). H. cordifera was collected from sandy bottom (coarse and medium sand) and rubble bottom with dredge (90% of spms) and van Veen grab.
Distribution. Temperate Northern Atlantic (realm), Warm Temperate Northwest Atlantic (province): Carolinian and Northern of Gulf of Mexico. Tropical Atlantic (realm), Tropical Northwestern Atlantic (province): Floridian to Eastern Caribbean (Hendler et al. 1995; Pomory 2007; Miloslavich et al. 2010); Tropical Southwestern Atlantic (province): Northeastern and Eastern Brazil (Lima-Verde 1969; Magalhães et al. 2005; Manso et al. 2008; Oliveira et al. 2010). Temperate South America (realm), Warm Temperate Southwestern Atlantic (province): Southeastern Brazil (Tommasi 1970; Manso & Absalão 1988; Absalão 1990; Pires-Vanin et al. 1997; Capítoli & Monteiro 2000; Capítoli & Bemvenuti 2004; Borges & Amaral 2005; Netto et al. 2005; Pires-Vanin et al. 2014).
From intertidal up to 50 m depth (Borges & Amaral 2005; Alvarado & Solís-Marín 2013). The present study samples occurred at depths ranging from 9 to 21.5 m.
Selected references. Bosc (1802): p. 138 [as Asterias cordifera]; Lyman (1865): p. 137, P 1. I. fig. 1–3; Hendler (2011): p. 45, fig. 1a–c [as Hemipholis cordifera]; Thomas (1962): p. 686, fig. 22; Tommasi (1970): p. 20, fig. 12–13; Albuquerque (1986): p. 160, fig. 26a–c; Monteiro (1987): p. 22, fig. 1a–d; Hendler et al. (1995): p. 143, fig. 66; Borges & Amaral (2005): p. 248, fig. a–c; Manso et al. (2008): p. 186, fig. 13a–c [as Hemipholis elongata]; Ayres (1852): p. 250 [as Ophiolepis uncinata]; Say (1825): p. 146 [as Ophiura elongata].
description: Published as part of Alitto, Renata A. S., Bueno, Maristela L., Guilherme, Pablo D. B., Domenico, Maikon Di, Christensen, Ana Beardsley & Borges, Michela, 2018, Shallow-water brittle stars (Echinodermata: Ophiuroidea) from Araçá Bay (Southeastern Brazil), with spatial distribution considerations, pp. 1-66 in Zootaxa 4405 (1) on pages 46-47, DOI: 10.11646/zootaxa.4405.1.1, http://zenodo.org/record/3097993