Ctenocardia gustavi, Vidal & Kirkendale, 2007

Vidal, Jacques & Kirkendale, Lisa, 2007, Ten new species of Cardiidae (Mollusca, Bivalvia) from New Caledonia and the tropical western Pacific, Zoosystema 29 (1), pp. 83-107 : 98-103

publication ID	https://doi.org/ 10.5281/zenodo.5401696
persistent identifier	https://treatment.plazi.org/id/6C56265E-FFCF-FFBA-AE6E-B964FE49FEE3
treatment provided by	Marcus
scientific name	Ctenocardia gustavi
status	sp. nov.

Treatment

Ctenocardia gustavi View in CoL n. sp.

( Fig. 5 View FIG E-G; Table 7)

TYPE MATERIAL. — Holotype:1 cv, 14.2 × 13.0 × 10.8 mm. Paratypes (5): 1 cv, 14.0 × 13.1 × 10.6 mm; 1 rv, 20.0 ×

17.3 × (15.6) mm; 1 lv, 18.5 × 17.0 × (13.6) mm; 1 valve, 17.0 × 15.4 × (13.2) mm; 1 cv, 14.1 × 12.7 × 10.0 mm.

TYPE LOCALITY. — Expédition MONTROUZIER 1993, New Caledonia, Passe de Touho, outer slope of barrier reef, stn 1273, 20°50.4’S, 165°22.8’E, 20 m, hard bottom.

ETYMOLOGY. — Dedicated to Gustav Paulay, who first drew attention to a specimen of this species from Niue.

MATERIAL EXAMINED. — New Caledonia. Atelier LIFOU 2000, Baie du Santal, off Drueulu, stn 1413, 20°55.3’S, 167°03.0’E, 3-10 m, white sand, 1 rv. — Near Îlot Huca Hutigué, stn 1421, 20°52.4’S, 167°08.5’E, 4 m, coarse sand on hard bottom, 1 tiny valve. — Off Peng, stn 1423, 20°54.0’S, 167°07.3’E, 12 m, sandy bottom, 1 cv + 2 rv + 1 lv. — Baie de Gaatcha, stn 1424, 20°54.9’S, 167°03.0’E, 4 m, fine sand and seaweeds, 3 tiny valves. — Off Kiki, stn 1427, 20°47.6’S, 167°09.35’E, 10 m, coarse sand and corals, 1 cv + 1 valve. — Near Pointe d’Easo, stn 1429, 20°47.5’S, 167°07.1’E, 8-18 m, corals, 1 rv. — Pointe d’Easo, stn 1430, 20°47.5’S, 167°07.1’E, 20-25 m, corals with sediments, numerous small cv + valves. — Near Pointe d’Easo, stn 1434, 20°52.5’S, 167°08.1’E, 5-20 m, hard bottom, 2 cv + 3 rv + 1 lv (second and third paratypes). — Pointe Lefèvre, stn 1435, 20°55.2’S, 167°00.7’E, 5-30 m, 1 rv. — Baie de Gaatcha, stn 1436, 20°55.5’S, 167°04.2’E, 10-20 m, corals, 2 small cv. — Pointe de Chépénéhé, stn 1438, 20°47.7’S, 167°09.35’E, 16 m, sand, several valves. — Pointe de Chépénéhé, stn 1439, 20°47.7’S, 167°09.35’E, 5-30 m, hard bottom, 2 cv. — Cap Aimé Martin, stn 1442, 20°46.4’S, 167°02.0’E, 47 m, wall bottom, several small valves. — Off Peng, stn 1443, 20°53.8’S, 167°07.3’E, 48-52 m, wall bottom, several small valves. — Baie de Gaatcha, stn 1444, 20°55.0’S, 167°05.2’E, 9-20 m, pebbles and coarse sand, several valves. — Baie du Santal, Mépinyo, 20°50.8’S, 167°09.7’E, 10-12 m, 3 lv + 3 rv. — Near Cap Aimé Martin, stn 1448, 20°45.8’S, 167°01.65’E, 20 m, hard bottom, 1 cv. — Near Cap Aimé Martin, stn 1450, 20°45.8’S, 167°01.65’E, 27-31 m, hard bottom, 3 small cv. — Between Cap Mandé and Cap Lefèvre, stn 1452, 20°54.6’S, 167°02,1’E, 2-25 m, hard bottom, 1 cv (first paratype). — Same locality as previous, stn 1453, 20°54.6’S, 167°02.1’E, 21-30 m, hard bottom with gorgons, 1 cv + 1 rv. — Cila, Baie du Santal, stn 1456, 20°49.3’S, 167°10.4’E, 25-30 m, wall, 1 lv. — Off Ngoni, stn 1458, 20°46.7’S, 167°03.1’E, 17-24 m, 1 cv + 2 rv + 1 lv. — Baie de Gaatcha, stn 1463, 20°55.05’S, 167°03.35’E, 20-30 m, sand and coral fragments, 1 cv + 1 rv + 4 lv.

Solomon Islands. SALOMON 1 2001, stn DW 1822, 9°51.8’S, 160°51.8’E, 51-54 m, 1 valve.

Philippines. PANGLAO 2004, Panglao Island, Napaling, stn S28, 9°37.2’N, 123°46.4’E, 28-32 m, reef wall with small caves, 24.VI.2004, 1 valve. — Bohol Island, Baklayon Takot, 9°37.1’N, 123°52.6’E, 8-15 m, 1 cv.

Niue Island. Niue, 2 km N of Alofi wharf, near base of outer reef slope, 26-30 m, in sand pockets, 1986, B. Holthuis & G. Paulay, 1 lv (fourth paratype) ( FLMNH 297515, BNIUE 187). — Niue, off Alofi wharf, deep sand channel, in sand 27-33 m, B. Holthuis & G. Paulay, 1986 and 1991, 2 rv ( FLMNH 297516, BNIUE 091). — Niue, North Alofi, off water tank, outer reef slope, terrace 28-30 m, Holthuis & Paulay, 1991, 1 rv ( FLMNH 297514, BNIUE 413).

Mariana Islands. Guam, Agana Bay, 91-122 m, 1989, B. D. Smith, 3 valves ( FLMNH 287333). — Guam, S Orote, 2000, L. Kirkendale, 1 cv ( FLMNH 288939). — Guam, Anae Is., south fore reef, 20 m, 1999, G. Paulay, 1 cv (fifth paratype) ( FLMNH 288940). — Guam, off Cocos, west side, site No. 2, biological dredge, 73-92 m, 2000, several valves and small cv ( FLMNH 288124).

Caroline Islands. Palau, south side of Malakal Channel, slope of reef, c. 8 m, 1996, G. Paulay, 1 rv ( FLMNH 296965).

Papua New Guinea. Louisiade Archipelago, fringing reef slope, muddy sand, 6 m, 1998, L. Kirkendale, 1 cv ( FLMNH 288925). — Bismarck Archipelago, Tungelo Island, Mascot Channel, on coral reef rubble ledge, 40 m, 2°40.79’S, 150°25.970’E, 2.VII.2003, L. Kirkendale, 1 live-collected cv ( FLMNH 351689).

Indonesia. Sulawesi, CCW 1999, stn 12, 00°29.28’S, 122°04.21’E, 30 m, G. Paulay, 1 lv ( FLMNH 280281, BSULA 35). — CCW 1999, stn 18, 0°21.13’S, 121°50.28’E, 1-18 m, 1 small lv ( FLMNH 280131, BSULA 48). — CCW 1999, stn 19, 0°20.28’S, 121°55.45’E, 1-4 m, 1 small cv ( FLMNH 280076, BSULA 50). — CCW 1999, stn 20, 0°18.41’S, 121°58.45’E, 12-16 m, 4 lv ( FLMNH 280199, BSULA 52). — CCW 1999, stn 21, 0°11.39’S, 122°11.02’E, 4-32 m, 1 rv ( FLMNH 280350, BSULA 53).

DISTRIBUTION. — Widespread in the tropical West Pacific from Mariana and Caroline Islands to Indonesia (Sulawesi), Papua New Guinea, New Caledonia and Niue Island.

DESCRIPTION

Shell small ( H = 10-20 mm), inequilateral, with posterior slope straight to slightly concave, markedly depressed and separated from the median area by a strong keel; medio-posterior slope rather variable rounded to moderately pointed, anterior margin rounded.

Lunular area narrow, with raised margin; lunule present but extremely small, situated just behind the anterior cardinal in the right valve (see Fig. 2F View FIG ).

Exterior grey-white to beige with irregularly disposed, concentrically arranged maroon-brown spots; on the posterior slope spots larger and more regularly disposed. Interior always with several maroon coloured zones, with a ray along the medio-posterior angle, a spot on the part of the lunular area close to the small lunule and a ray along the ventral margin of the hinge below the ligament.

Anterior laterals slightly closer to cardinals than to posterior laterals. Second posterior lateral tooth in the right valve rarely observed.

Ribs 39-45; 10-12 on the posterior slope.

Posterior ribs slightly trapezoid to square-sided, tops flatly rounded and much wider than the finelystriated interstices. Close, thin, arched threads on tops of ribs, at irregular intervals along the rib, some threads becoming broader, higher and longer, with pointed extremities overhanging interstices. These broader transverse nodes are irregularly distributed, touching to slightly separated by a variable number (up to 10) of thin threads. Anterior rib ornaments similar to posterior ones.

MICROHABITAT

Ctenocardia gustavi n. sp. has been recovered from depths of 1 to 54 m. It has been collected live by one of us ( LK) in Papua New Guinea at a depth of 40 m, where it was shallowly buried on a narrow coral rubble rock ledge.

REMARKS

Ctenocardia gustavi n. sp. resembles the American Ctenocardia (Americardia) media (Linnaeus, 1758) and the American fossil species Trigonocardia decidua ( Vokes, 1977) from the Oligo-Miocene Chipola Formation of Florida in several characters, including shape, hinge and rib morphology.In the tropical west Pacific, C. gustavi n. sp. is found sympatrically with six recognized conspecifics: C. fornicata (Sowerby, 1841) , C. victor (Angas, 1872) , C. translatum , C. symbolica Iredale, 1929 , C. perornata Iredale, 1929 and C. fijianum n. sp. Although these taxa are similar in gross shell shape, rib number and distribution, they differ significantly in aspects of rib morphology.

Ctenocardia (Microfragum) subfestivum n. sp. ( Fig. 5 View FIG H-J; Table 8)

TYPE MATERIAL. — Holotype: 1 cv, 10.3 × 10.6 × 7.6 mm (ex Vidal coll. ex Boutet, MNHN). Paratypes (3): 1 cv, 9.1 × 9.0 × 7.2 mm ; 1 cv, 8.5 × 8.8 × 7.6 mm; 1 rv, 10.1 × 10.3 × (8.0) mm.

TYPE LOCALITY. — French Polynesia, Tahiti, Afaahiti, 50 m.

ETYMOLOGY. — In reference to the species C. (M.) festivum , a species it has been previously confused with.

MATERIAL EXAMINED. — New Caledonia. LAGON, Huon Atoll, stn 436, 18°06’S, 162°50’E, 45 m, 1 cv. — Yate, SE Lagoon, stn 634, 21°56.5’S, 166°46.5’E, 36-42 m, 1 cv (second paratype). — Grand Récif Mangalia, NE Lagoon, stn 853, 20°41’S, 165°07’E, 27 m, 1 rv. — Îles Belep, N Lagoon, stn 1139, 19°24’S, 163°47’E, 39 m, 2 rv. — Îles Belep, stn 1158, 19°10’S, 163°07’E, 48 m, 1 cv + 3 lv.

CHALCAL 1, Bellona Reef, Coral Sea, stn DC 60, 21°48.65’S, 159°27.95’E, 45 m, 2 rv + 2 lv. — Chesterfield Atoll, stn DC 15, 19°23.30’S, 158°38.60’E, 65 m, 1 rv. — Same region, stn DC 26, 19°10.72’S, 158°34.95’E, 48 m, 1 cv. — Same region, stn DC 39, 20°28.90’S, 158°48.70’E, 40 m, 3 cv.

MUSORSTOM 4, Grand-Passage, near Pelotas Atoll (N external zone), stn DW 162, 18°35’S, 163°10’E, 525 m, 1 rv + 1 lv.

CORAIL 2, Banc Fairway, Chesterfield, stn DW 02, 20°50.48’S, 161°37.25’E, 62 m, 2 cv + 1 lv. — Same region, stn DW 03, 20°50.42’S, 161°34.19’E, 58 m, 1 lv. — Same region, stn DW 04, 20°52.38’S, 161°36.56’E, 3 rv. — Same region, stn DW 08, 20°52.07’S, 161°38.21’E, 63 m, 1 cv + 3 rv + 2 lv. — Same region, stn DW 09, 20°53.00’S, 161°35.32’E, 62 m, 1 cv + 1 rv. — Same region, stn DW 10, 20°52.49’S, 161°41.02’E, 60 m, 3 rv + 2 lv. — Chesterfield Lagoon, stn DW 31, 19°24.86’S, 158°45.03’E, 57 m, 1 cv. — Same region, stn DW 42, 19°21.53’S, 158°28.83’E, 45 m, 1 cv. — Same region, stn DW 46, 19°18.54’S, 158°20.00’E, 21 m, 2 cv. — Same region, stn DW 72, 19°15.30’S, 158°20.89’E, 32 m, 1 cv. — Same region, stn DW 87, 19°06.14’S, 158°59.94’E, 31 m, 2 rv + 3 lv. — Same region, stn DW 88, 19°05.98’S, 158°55.85’E, 32 m, 5 valves. — Same region, stn DW 96, 19°06.00’S, 158°41.92’E, 41 m, 1 rv. — Same region, stn DW 122, 19°28.17’S, 158°17.06’E, 32 m, 1 cv. — Same region, stn 128, 19°27.89’S, 158°30.44’E, 38 m, 1 rv. — Same region, stn DW 135, 19°31.37’S, 158°19.14’E, 46 m, 1 cv. — Same region, stn DW 137, 19°34.00’S, 158°14.60’E, 32 m, 2 cv. — Same region, stn DW 143, 19°37.40’S, 158°25.16’E, 45 m, 2 cv. — Same region, stn DW 144, 19°27.73’S, 158°23.28’E, 50 m, 1 rv. — Same region, stn DW 156, 19°48.95’S, 158°21.03’E, 42 m, 1 cv (first paratype).

Atelier LIFOU 2000, Baie du Santal, near Pointe Easo, stn 1430, 20°47.5’S, 167°07.1’E, 20-25 m, reefal environment, 1 rv + 1 lv. — Cap Aimé Martin, stn 1442, 20°46.4’S, 167°02.0’E, 47 m, on bottom of wall, 3 rv + 1 lv.

French Polynesia. Moorea-Tiahura, external slope, 32 m, 1 valve (ex Falconetti coll., MNHN).

Wallis and Futuna. MUSORSTOM 7, Banc Waterwitch, stn DW 537, 12°30’S, 176°41’W, 325-400 m, 1 rv (third paratype). — Same region, stn 538, 12°31’S, 176°40’W, 275-295 m, 1 rv. — Same region, stn DW 529, 12°31’S, 176°40’W, 500 m, 2 rv + 4 lv. — Banc Combe, stn CP 552, 12°16’S, 177°28’W, 786-800 m, 1 rv. — Wallis, stn DW 601, 13°19’S, 176°17’W, 350 m, 1 rv.

Tonga. BORDAU 2, Haa’pai Group, stn DW 1602, 20°49.19’S, 174°57.08’W, 263-320 m, 1 lv.

Austral Islands. BENTHAUS 2002, Banc Président Thiers, stn DW 1934, 24°40.6’S, 145°57.4’W, 560-1150 m, 1 lv. — Banc Président Thiers, stn DW 1926, 24°38.2’S, 146°00.8’W, 50-90 m, 1 lv. — Rimatara, stn DW 2015, 22°38.2’S, 152°49.5’W, 250-280 m, 1 rv. — Banc Président Thiers, stn DW 1927, 24°39’S, 146°01.6’W, 95-100 m, 1 rv + 2 lv. — Tubuai, stn DW 1958, 23°19.6’S, 149°30.3’W, 80-150 m, 1 cv + 8 rv + 3 lv. — Banc Président Thiers, stn DW 1932, 24°40.8’S, 146°01.5’W, 500-800 m, 1 rv. — Tubuai, stn DW 1955, 23°18.5’S, 149°25.7’W, 750-800 m, 1 rv. — E Coast of Rurutu, stn DW 2003, 22°27.6’S, 151°18.9’W, 250-330 m, 5 rv + 6 lv. — Tubuai, stn DW 1961, 23°20.9’S, 149°33.5’W, 470-800 m, 1 rv. — Tubuai, stn DW 1959, 23°19.8’S, 149°30.4’W, 95-380 m, 2 rv + 3 lv. — Tubuai, stn DW 1962, 23°20.8’S, 149°33.4’W, 470-800 m, numerous valves. — E Coast of Rurutu, stn DW 2004, 22°27.7’S, 151°18.7’W, 430-850 m, 1 rv. — Port of Rurutu, stn DW 2002, 22°26.7’S, 151°20.1’W, 247-250 m, 1 rv.

Japan. Okinoshima, Kochi pref., 2 cv ( NSMT 42313).

DISTRIBUTION. — Western Pacific from Japan to New Caledonia and Polynesia.

DESCRIPTION

Shell small ( H = 7 to 10 mm), as long as high, inequilateral with posterior slope oblique, posterior margin slightly truncate and somewhat expanded and posterior angle well marked, rounded and not carinate.

Lunular area small with protruding but not raised margin; lunule itself very short, extending in right valve to just behind the anterior cardinal.

Exterior grey-white, light brown or pink, with some irregular darker zones; interior white, slightly pink in the umbonal cavity. Anterior part of hinge line pink.

Ribs 37-41.

Ribs rounded in cross-section, covered with thin, imbricated contacting lamellae, rather irregular in strength and size ( Fig. 2M View FIG ); they become more tubercular on anterior and posterior regions of the valve.

MICROHABITAT

Ctenocardia subfestivum n. sp. was recovered from 20- 400 m. This is slightly deeper than the average depth of C. (M.) festivum , a species with a similar distribution and very similar gross shell features. This observation is based on examination of a limited number of either live-collected or freshdead (ligament intact or valves found together with no subsequent encrustations) specimens of both species.

REMARKS

Ctenocardia (Microfragum) subfestivum n. sp. differs from C. (M.) festivum in gross shell shape by being more asymmetrical and oblique, with a more truncate posterior margin and a more marked posterior angle or keel. Ctenocardia (M.) subfestivum n. sp. also has more ribs, a characteristic pink hinge coloration and less numerous but more irregular lamellae compared with C. (M.) festivum ( Fig. 5 View FIG K-M). Moreover, on the medio-posterior external shell region, ribs of the new species are more squared and interstices are wider (about half of the ribs), with limits between ribs and interstices sharper and less progressive than in C. (M.) festivum ( Fig. 5 View FIG K-M).