Hemipholis cordifera ( Bosc, 1802 ),

Alitto, Renata A. S., Bueno, Maristela L., Guilherme, Pablo D. B., Domenico, Maikon Di, Christensen, Ana Beardsley & Borges, Mic, 2018, Shallow-water brittle stars (Echinodermata: Ophiuroidea) from Araçá Bay (Southeastern Brazil), with spatial distribution considerations, Zootaxa 4405 (1), pp. 1-66: 46-47

publication ID

https://doi.org/10.11646/zootaxa.4405.1.1

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lsid:zoobank.org:pub:D33BF380-5AF7-4645-86C7-9981C528EAF0

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http://treatment.plazi.org/id/03C3B82F-9201-C956-07C8-FB51FB083961

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Plazi

scientific name

Hemipholis cordifera ( Bosc, 1802 )
status

 

Hemipholis cordifera ( Bosc, 1802) 

( Fig. 16View FIGURE 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. 16AView FIGURE 16). Ventral interradius without scales ( Fig. 16BView FIGURE 16). 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. 16CView FIGURE 16).

Arms: dorsal arm plates semi-circular to half-circle, twice as wide as long, straight proximally, rounded distally and contiguous ( Fig. 16D,FView FIGURE 16). Ventral arm plates hexagonal, as long as wide and contiguous ( Fig. 16E,GView FIGURE 16). One elongated tentacle scale, half-length of one ventral arm plate. Three slender pointed arm spines ( Fig. 16EView FIGURE 16).

Lateral arm plates ( Fig. 16H,IView FIGURE 16): 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. 16JView FIGURE 16). Zygocondyles dorsalwards converging and zygosphene fused with pair of zygocondyles ( Fig. 16KView FIGURE 16). Dorso-distal muscular fossae transformed distalwards clearly projecting beyond zygocondyles (true keel) ( Fig. 16LView FIGURE 16). Zygosphene projecting beyond ventral edge of zygocondyles with projecting part shorter than zygocondyles ( Fig. 16MView FIGURE 16).

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  ].