Agononida rubrizonata, Macpherson, Enrique & Baba, Keiji, 2009

Macpherson, Enrique & Baba, Keiji, 2009, New species of squat lobsters of the genera Agononida and Paramunida (Crustacea: Decapoda: Anomura: Galatheidae) from the western Pacific, Zootaxa 2024, pp. 56-68 : 60-63

Agononida rubrizonata n. sp.

( Figs. 2 F, 3, 4)

Munida incerta . — Baba, 1994: 12 (off Central Queensland, 497–503 m). — Macpherson, 1994: 478 (part), fig. 74 ( New Caledonia, Loyalty Islands, 640– 580 m). — Wu et al., 1998: 113 (part), fig. 26E ( Taiwan, depths unknown). Agononida incerta . — Ahyong & Poore, 2004: 8 (part) (New South Wales, 270–641 m).

Material examined. The 16.3 mm male ( NTOU A00889 ) from Tawan is the holotype. The other specimens are paratypes.

TAIWAN. Commercial trawl, Su-ao, Yilan County, NE Taiwan, ca. 500 m, 05.12.1997: 1 ovigerous female (16.8 mm) ( NTOU A00882 ). — ca. 350 m, 07.08.1996: 1 male (25.6 mm), 1 female (18.5 mm) ( NTOU A00883 ). — no depth record, 05.12.1997: 2 males (12.5, 21.6 mm), 2 ovigerous females (14.2, 15.3 mm) ( NTOU A00884 ). — no depth record, 08.04.1999: 3 males (13.9–15.1 mm) ( NTOU A00885 ). — no depth record, 29.07.2004: 1 male (12.6 mm) ( NTOU A00886 ), 1 ovigerous female (20.5 mm), 2 females (10.6, 15.5 mm) ( NTOU A00887 ). — no depth record, 09.03.2005: 1 male (15.0 mm) ( NTOU A00888 ). — 10.03.2005: 8 males (15.0– 16.5 mm) [male 16.3 mm is holotype ( NTOU A00889 )], 2 ovigerous females (16.6, 16.9 mm), 6 females (15.0– 15.5 mm) ( NTOU A00890 ).

VANUATU. SANTO Stn AT 71, 15°44.3’S, 167°03.0’E, 0 6.10.2006, 603– 736 m: 1 male (17.3 mm) (MNHN-Ga 6689). — Stn AT 106, 15°02.2’S, 166°55.4’E, 16.10.2006, 548– 560 m: 1 male (16.9 mm), 1 female (10.6 mm) (MNHN-Ga 6690).

NEW CALEDONIA. BATHUS 1 Stn CP 658, 27º13.45’S, 165º55.12’E, 12.03.1993, 515– 580 m: 1 male (23.6 mm) (MNHN-Ga 6691).

LOYALTY ISLANDS. MUSORSTOM 6 Stn 466, 21º05.25’S, 167º32.20’E, 21.02. 1989, 540 m: 1 female (17.5 mm) (MNHN-Ga 2727).

Etymology. From the Latin ruber (red) and zonatus (banded), referring to red bands on pereopods, characteristic of the species.

Description. Carapace slightly wider than long, with numerous transverse ridges and scales. Transverse ridges usually interrupted in all regions, with dense, short non-iridescent setae. Gastric region with 2 epigastric spines; 3 postcervical spines on each side, decreasing in size posteriorly. Posterior border of carapace unarmed. Frontal margins slightly oblique. Lateral margins slightly convex. First spine at anterolateral angle strong, reaching or slightly overreaching level of sinus between rostrum and supraocular spines. Second spine in front of cervical groove one-third length of preceding one. Branchial margins with 4 spines, first spine much smaller than and located distinctly ventral to level of others. Rostrum spiniform. Rostral spine 0.4 postorbital carapace length, nearly straight and horizontal. Supraocular spines slightly thicker than rostral spine, clearly overreaching midlength of rostral spine and slightly exceeding corneas, directed slightly upwards.

Thoracic sternites with numerous short striae. Anterior part of fourth sternite slightly narrower than third; median part of posterior margin of third sternite contiguous to fourth sternite. Transverse ridges on fifth, sixth and seventh sternites obtuse, feebly granulated.

Second to fourth abdominal somites squamate, with 4 spines on anterior ridge; posterior ridge of fourth somite with median spine. Telson with numerous scales; males with strong lateral process.

Eyes large, maximum corneal diameter about 0.3 times distance between bases of anterolateral spines.

Basal segment of antennule (distal spines excluded) about 0.3 carapace length, elongate, overreaching corneae, with 2 distal spines, mesial spine clearly longer than lateral spine; 2 spines on lateral margin, proximal one small, distal one reaching or exceeding distolateral spine. First segment of antennal peduncle with long distomesial process clearly overreaching end of antennular and antennal peduncles. Second segment with strong distomesial spine exceeding third segment, accompanying small spine at mesial base; distolateral spine smaller than distomesial. Third and fourth segments unarmed.

Mxp3 ischium about twice length of merus measured along dorsal margin, flexor margin with long distal spine. Merus with well-developed spine on flexor median margin; extensor margin with long distal spine.

P1 squamous, with some uniramous and plumose setae and some iridescent setae on mesial borders of merus and carpus, about 3.5–4.0 times carapace length; merus 1.3–1.5 times carapace length, carpus 3–4 times longer than broad and slightly shorter than palm; palm 4–5 times longer than broad and as long as or slightly shorter than fingers. Merus armed with row of spines on mesial, ventral and dorsal borders. Carpus and palm with several spines on lateral, dorsal and mesial margins. Fingers unarmed, each with longitudinal carina dorsally and ventrally, distally ending in incurved sharp spine, fixed finger ending in 2 spines accommodating opposite distal spine of movable finger when closed.

P2 3.5–3.8 times carapace length; merus 1.4–1.6 times longer than carapace, 8–10 times longer than high, 3.5–4.5 times carpus length and 1.5–1.7 times propodus length; propodus 9–10 times as long as high, 1.4–1.8 times dactylus length; when extended forward, propodus reaching or slightly overreaching end of P1 merus. Merus with dorsal and ventral spines increasing in size distally, distal spine strong. Carpus with strong extensor and flexor distal spine, and 1–2 additional small extensor marginal spines. Propodus with row of movable spinules on flexor margin. Dactylus slightly curving distally, flexor margin slightly curving, with 7–11 movable spinules in proximal half, unarmed in distal half. P3 as long as P2, and slightly longer than P4; armature and article proportions of P3 and P4 similar to those of P2. Extensor margins of P2–4 with dense, uniramous and plumose setae, and some iridescent setae; flexor margins of dactyli with corneous setae.

Colour in life. Ground colour of carapace, second to fourth abdominal segments and pereopods pale orange. P1 with red band on distal portion of merus, proximal part of palm and base of fingers. P2–P4 with red band on distal part of merus and propodus.

Remarks. As mentioned under the “Remarks” of A. incerta , the new species is distinguished from A. incerta by having a strong process on the lateral margin of the telson in males and red bands on P 1–4 in both sexes.

The numerous recorded occurrences of A. incerta in the Western Pacific and Indian Oceans, therefore, need to be revised. In the present paper we have only reviewed some of these records. Molecular markers can also distinguish the two species, e.g., COI shows a interspecific genetic divergence of 3.3–3.8%, but the intraspecific divergence is 1.1–1.2%, 16S shows interspecific values of 0.6–0.8%, but the intraspecific divergence is also 0.0–0.2% (Chia-Wei Lin, NTOU, personal communication).

Ahyong & Poore (2004) noted that Munida sp. of Jones & Morgan (1994) and Agononida sp. cf. squamosa of Jones & Morgan (2002) appeared to belong to this new species. However, their photographs show that the red bands on the distal portions of P2–4 meri and carpi are distinctly remote from the distal end of respective segment, not contiguous to the segment as in A. rubrizonata . Very possibly this western Australian specimen is a different new species.

Distribution. Taiwan, Vanuatu, New Caledonia, New South Wales, Queensland, and northwestern Australia, in 270– 641 m.

Figures

FIGURE 2. Agononida incerta (Henderson, 1888). A – D, G – H: male, 35.6 mm (ZMUC-CRU- 11555). Philippines, off Zamboanga. E, male, 21.8 mm, Taiwan (NTOU A 00875). F, A. rubrizonata n. sp., male, 25.6 mm, Taiwan (NTOU A 00883). A, telson, dorsal. B, sternum. C, left antennule and antenna, ventral. D, ischium and merus of right third maxilliped, lateral. E-F, merus right P 1, dorsal. G, merus right P 4, lateral. H, carpus, propodus and dactylus right P 4, lateral. Scale: = 4 mm.