Plagiobrissus grandis (Gmelin, 1791)

Guilherme, Pablo Damian Borges, Bueno, Maristela de Lima, Metri, Rafael, Baptista-Metri, Cassiana, Loose, Robin Hilbert & Tavares, Yara Aparecida Garcia, 2023, First record of the heart urchin Plagiobrissus grandis (Gmelin, 1791) (Echinodermata: Echinoidea) in the coastal region of Paraná, southern Brazil, Papéis Avulsos de Zoologia 63, pp. 1-8 : 2-4

Plagiobrissus grandis (Gmelin, 1791) Figs 1 , 2 , 3 and 4

Echinus grandis Gmelin, 1791 – Gmelin, 1791: 3200.

Spatangus pectoralis (Lamarck,1816) – Lamarck,1816: 29.

Eupatagus pectoralis (Lamarck, 1816) – D′Archiac & Haime, 1853: 217-218.

Metalia pectoralis (Lamarck,1816) – Agassiz,1872:144-145.

Plagiobrissus pectoralis (Lamarck,1816) –Pomel,1883:29-30.

Eupatagus (Plagiobrissus) grandis (Gmelin, 1791) – Cooke, 1942: 54.

Plagiobrissusgrandis (Gmelin,1791)– Clark,1917:207-208, pl. 146: figs. 21, 22. Mortensen, 1951: 496-498, pl. 40-41, 63:figs.13,16.Tommasi,1958:7, pl. 11: fig.4. Tommasi, 1966: 20, pl. 5b. Kier, 1975, fig. 2-5; pl. 1-3; pl. 4: figs. 1, 2. Martins et al., 2018: 16-18, figs. 14-15. Gondim et al., 2018: 47-49, fig. 17.

Material examined: Parque Nacional Marinho das Ilhas dos Currais (Paraná State) – 10 m, 02-VIII-2015, // Maristela Bueno det. 2018. 1 ♀ (UNESPAR – ECH 033); Djanka ferry wreck (Paraná State) – 26 m, 2016 // Robin Hilbert Loose, personal observation .

Diagnosis: The specimen (ECH 033) dimensions were 155.65 mm in length, 118.93 mm in width, and 41.31 mm in maximum height( Fig.3 ),test oval and flattened,round- ed anteriorly and truncate posteriorly ( Fig. 1 ). The carapace is extremely thin and fragile, brittle. At the top of the test, the apical disc plating is ethmolytic, with 4 symmetrically sized gonopores.The ambulacral zones draw 4 petals radiating on the upper face from the apical system, these petals are slightly inserted into the test, without forming a gutter or deep furrow. At the front of the test, a shallow notch, without perforations, connects the apical system to the front concavity, under which opens the mouth or peristome ( Fig. 4A ), which is in an anterior and ventral position, and relatively small (18.48 mm) representing 15% of the total width of the organism. Labrum short, in contact with both sternal plates ( Fig. 4A ). Between these petals extend the inter-ambulacral zones covered with large tubercles in relief: these are the supports for the long spines (length = 25.35 ± 7.19 mm; width = 0.75 ± 0.19 mm; n = 10), with short, backward-curving spines between them ( Figs. 1 and 2 ). The peripetal fasciole is covered with very small spines (length = 4.12 ± 1.11 mm;width = 0.29 ± 0.05 mm;n = 10). In the middle of the ventral face is the plastron ( Fig. 3A ), particularly narrow, with rectilinear and parallel edges. Outside the plastron, there are longer spines ( Fig. 3B ) with a fan-shaped base (length = 20.07 ± 5.04 mm; width = 0.60 ± 0.11 mm; base width = 1.38 ± 0.17 mm; n = 10). The spatulate spines in the plastron ( Fig. 3C ) are thinner and shorter than on the rest of the oral surface (length = 9.11 ± 1.83 mm; width = 0.51 ± 0.06 mm; tip width = 0.68 ± 0.08 mm; n = 10). The suture between the sternal and episternal plates is very marked and concave. The terminal (posterior) anus, surrounded by a subanal fasciole shield-shaped ( Fig. 4B ) with large plates. Periproct large (10.63 mm), tear-shaped ( Figs. 4B and C ), truncate, surrounded by anal fasciole ( Fig. 4C ).

Colour: Living specimens are light brown ( Fig. 1 ), naked test light beige.

Distribution: North America and Caribbean Sea (Palomares & Pauly, 2022). In Brazil from Alagoas, Bahia, São Paulo (Tommasi, 1958, Netto et al., 2005, Gondim et al., 2018), and Paraná (present study), including Trindade Island (Martins et al., 2018). This is the first record of this species in Paraná State ( Fig. 5 ). From depths of 1 to 210 m, but most common in less than 50 m (Serafy, 1979).

Figures

Figure 1. Live specimen Plagiobrissus grandis (ECH 033) in an aquarium. (A) oral view and (B) aboral view.(C) Image of the covering behavior.Photos: Robin Hilbert Loose.

Figure 2. Fixedspecimen Plagiobrissusgrandis (ECH 033) – captured at approximately10mdepthnear ParqueNacionalMarinhodas IlhasdosCurrais (Paraná State). Aboral view (left)and oral view (right).Photo:Maristela Bueno.

Figure 3. Oral view specimen Plagiobrissus grandis (ECH 033) – captured at approximately 10 m depth near Parque Nacional Marinho das Ilhas dos Currais (Paraná State).Oral view and plastron (A), long spines fan-shaped base,localized outside the plastron (B) and spatulate spines in the plastron (C).Photo:Maristela Bueno.

Figure 4. Fixedspecimen Plagiobrissusgrandis (ECH 033) – captured at approximately10mdepthnear ParqueNacionalMarinhodas IlhasdosCurrais (Paraná State). Oral view,detail of peristome (A), subanal fasciole (B) and anal fasciole and periproct (C).Photo:Maristela Bueno.

Figure 5. Geographical distribution of Plagiobrissus grandis in America.The dots represent the previous and new records of the species.Map background generat- ed with package ̎ggmap″ usingGoogle Maps API.