Cassidulus infidus Mortensen 1948b

Souto, Camilla, Manso, Cynthia L. C. & Martins, Luciana, 2011, Rediscovery and redescription of Cassidulus infidus (Echinoidea: Cassidulidae) from Northeastern Brazil, Zootaxa 3095, pp. 39-48 : 40-46

Cassidulus infidus Mortensen 1948b

( Figs. 1–7 )

Cassidulus infidus Mortensen 1948a: 215 ; Mortensen 1948b: 67; Tommasi 1966: 21 [as Cassidulus infindus ]; Manso et al. 2008: 184.

Material. Baía de Todos os Santos, BA, Brazil (12º48' S; 38º30' W), 29 August 1996, 3.5 m, 6 specimens (UFBA- 314); Salvador, BA, Brazil (13º01’ S; 38º29’ W), February 2008, 11 m, 1 specimen (UFBA-757); Bahia, Brazil, 1 specimen (SMNH-Type-4859).

Comparative material. Cassidulus caribaearum – Anegada, Virgin British Islands, 2 specimens ( CASIZ 112633: 12.89 and 16.21 mm in TL); Cassidulus mitis – Rio de Janeiro, RJ, Brazil, 3 specimens (UFBA-756: 26.76 and 31.76 mm in TL; IBZ/UFRJ-EE338: 20 mm in TL).

Amended Diagnosis. Lateral edges of test straightened, anterior and posterior margins rounded. Aboral surface inflated with greatest height posterior to the apical disc; oral surface strongly concave. Phyllodes with one row per half ambulacrum. Large deep pits on posterior ambulacrum. Periproct small, wider than long, almost round; periproctal groove narrow and deep.

Redescription. Test small, wide and low ( Fig. 1 A–D); largest specimen with 12.86 mm in length, 10.44 mm wide and 5.07 mm in height. Aboral surface inflated ( Fig. 2 F) with greatest height posterior of apical disc on a small elevation above the periproct ( Fig. 2 A, C); oral surface ( Fig. 2 B, D) concave, especially in the midline. Test height between 40–52% of TL ( Table 1 ). Smallest specimens (6.67–8.84 mm of TL) oval in outline. Large specimens (9.46–12.86 mm in length) have straightened lateral edges, and rounded anterior and posterior margins, being slightly wider in the posterior region. Young specimens (3.58 – 3.68 mm in length) almost circular and flattened ( Fig. 2 G).

Apical disc: Anterior, monobasal ( Fig. 3 A), less than 40% of TL from anterior edge and bearing four genital pores. These were completely developed in individuals larger than 6.67 mm; however, they were opened only in the specimens with 7.71, 8.84 and 12.86 mm TL. Ocular plates small and differ in size from one another. Number of hydropores in madreporic plate varies according to the size of the specimen, but not exceeding 30 pores in the largest specimens.

Ambulacra: Petaloid region occupying 1/3 of the aboral region ( Fig. 1 A). Petals narrow; short (18–22% of TL); almost equal in length, with 10–12 pores per row in petals II, III and IV, and 10–16 in petals I and V (10–13 in inner and 14–16 in outer rows). Petal I slightly shorter than petal V; opened distally. Poriferous zones ( Fig. 3 B) almost equal in length. Two, rarely three, primary tubercles, surrounded by miliary tubercles between the consecutive pore pairs. Interporiferous zones of petals wider than a single poriferous zone.. Ambulacral plates single; pores rounded and approximately equal in size when in the same row, except for the three proximal pore pairs, which are smaller. Outer pores larger than inner. Outer and inner pores not conjugated by a deep furrow. One primary tubercle and 3–4 miliary spines in each ambulacral plate of petals. Plates beyond petals with small single pores.

Interambulacra: Interambulacral plates wide at the ambitus and narrowing towards the apical disc.

Floscelle: Bourrelets well developed ( Fig. 4 A), not tooth-like, bearing 40–55 spines which covers the entire peristomial aperture. Single buccal pore in each ambulacral basicoronal plate ( Fig. 4 B). Phyllodes single pored, parallel and enlarged near the peristome ( Fig. 4 C), with 6–8 pores in each row. Two to three (rarely four or five) sphaeridia ( Fig. 4 D) in deep pits (sometimes enclosed; Fig. 4 A), arranged in a double series along the midline of the phyllodes.

Peristome: Slightly wider than long (almost equant) ( Fig. 4 A, B), and located in a depression on the oral region of the test, displaced towards the anterior edge (center of opening situated 38–43% of TL from the anterior edge). Peristome of smallest specimens circular ( Fig. 2 G), becoming pentagonal as the individual grows.

Periproct: Supramarginal ( Fig. 2 E), wider than long, and situated in a deep depression near the posterior edge of test, beyond the petals ( Fig. 2 A). Anal opening surrounded by a fringe of depressed spines with serrated edges and placed in the top position (middle-left side). Periproct composed by eight large and four to seven small plates ( Fig. 5 A). Each periproctal plate bears 4–5 primary and 13-30 miliary tubercles ( Fig. 5 B), and tridentate pedicellariae. Periproct of smaller specimens almost circular in shape.

Naked zone: Along the midline of the entire oral surface ( Fig. 2 B, D), in ambulacrum III and interambulacrum 5, deeply pitted and bearing small and thin miliary spines, numerous in the former and sparsely distributed in the latter region.

Tuberculation: Slightly crenulate tubercles with circular scrobicules and small perforated mamelons ( Fig. 7 E). Oral tubercles larger than adoral ones.

Spines: Four types of primary spines cover the test: aboral spines short, thick, distally serrated, with enlarged tip, sometimes club-shaped ( Fig. 6 C); spines at bourrelets thick, serrated, slightly curved and with enlarged tip ( Fig. 6 D); oral spines near the edges are long, straight, smooth proximally, distally serrated ( Fig. 6 E) and positioned towards the center, partially covering the naked zone ( Fig. 2 D); spines above periproct long and straight, covering the whole depression ( Fig. 2 E), and proximally serrated ( Fig. 6 F). Miliary spines throughout the test small (aboral smaller than oral), serrated, widening distally where there is a crown ( Fig. 6 A, B).

Pedicellariae: Ophicephalous pedicellariae ( Fig. 7 A, B) sparsely distributed at aboral surface, but numerous on the margins. Coarse teeth only on blades; teeth on distal edge of blades longer and sharper than along its sides. Valves ending in a hook, which articulates with a hollow stalk, with a broad, smooth and circular neck. Tridentate pedicellariae ( Fig. 7 C, D) only around the periproct and on periproctal plates. Three large tridentate valves (c. 200 μm in length) mounted on thick and small stalk (c. 235 μm in length). Valves widen distally and bear fine teeth on their distal edges, which interdigitate with those on adjacent valves. Globiferous and triphyllous pedicellariae not found.

Figures

FIGURE 1. Drawings of Cassidulus infidus UFBA- 314 showing: shape of test in (A) aboral, (B) oral, (C) side and (D) posterior views. Scale bar is 2 mm long.

FIGURE 2. Cassidulus infidus SMNH-Type- 4859 (holotype): (A) aboral and (B) oral surface; UFBA- 314: (C) aboral, (D) oral and (E) periproctal surface of largest specimen; UFBA- 757: (F) side view of test; and UFBA- 314: (G) oral surface of smallest specimen. Scale bars are 2 mm long.

FIGURE 3. Drawings of Cassidulus infidus UFBA- 314 showing: (A) apical disc with four genital pores in dark gray, five ocular plates in light gray enclosing ocular pores, and hydropores represented by small open circles; and (B) poriferous and interporiferous zones of ambulacrum II, pore pairs in dark gray, miliary tubercles represented by small open circles and primary by two concentric circles. Scale bars are 0.5 and 0.1 mm long, respectively.

FIGURE 4. Drawings of Cassidulus infidus UFBA- 314 showing: (A) floscele with peristome aperture in light solid gray, bourrelets shaded, naked zone pits in dark solid gray, sphaeridial pits in solid black, phyllopores and primary tubercles represented by small open circles and three concentric circles, respectively, and (B) basicoronal plates around peristome aperture in light gray, from specimen 12.86 mm long; (C) internal oral surface of phyllode IV (phyllopores in solid black) from specimen 9.46 mm long; and (D) SEM of sphaeridium from pit in interambulacrum 5. Scale bars for A-C are 1 mm and for D is 10 µm long.

FIGURE 5. Drawings of Cassidulus infidus UFBA- 314 showing: (A) internal view of periproct from specimen 9.46 mm long; and (B) periproctal plate pattern showing primary tubercles represented by two concentric circles and miliary tubercles represented by small black circles from specimen 12.86 mm long. Scale bars are 0.5 mm long.

FIGURE 6. Drawings of Cassidulus infidus UFBA- 314 showing: miliary spines from (A) aboral and (B) oral surface; and primary spines from (C) aboral surface, (D) bourrelets, (E) oral surface, and (F) just under hood, near periproct. Scale bars are in µm.

FIGURE 7. SEM of external appendages of Cassidulus infidus UFBA- 314: (A) complete ophicephalous pedicellaria from the edge of the test, (B) single valve of ophicephalous pedicellaria depicted in (A), (C) external and (D) internal view of tridentate pedicellaria from periproctal plate; and (E) SEM of primary tubercle from the oral side of the test. Scale bars for A-D are 10 µm and for (E) is 100 µm long.

Tables

TABLE 1. Test measurements (in millimeters) of specimens of Cassidulus infidus.

Specimens	Length	Width	Height	TH/TL
UFBA-314 (1)	12.86	10.44	5.07	0.40
SMNH-Type-4859	10.03	7.80	5.33	0.53
UFBA-314 (2)	9.46	7.59	4.00	0.43
UFISITAB- ECH123 (1)	8.84	8.01	4.37	0.49
UFBA-757 (1)	7.98	6.57	3.71	0.46
UFBA-314 (3)	7.71	6.35	3.29	0.43
UFISITAB- ECH123 (2)	6.67	6.28	2.94	0.44
UFBA-314 (4)	3.68	3.26	0.60	0.16
UFBA-314 (5)	3.58	3.19	0.74	0.26