Coralliogalathea minuta, Rodríguez-Flores & Macpherson & Buckley & Machordom, 2018

CORALLIOGALATHEA MINUTA View in CoL SP. NOV.

(FIGS 8, 9)

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Material examined

Holotype: New Caledonia, Touho Island , 20.7833°S, 1 6 5. 2 1 6 7 ° E, S e p t e m b e r 1 9 9 3: M, 2. 6 m m (MNHN-IU-2013-17329). GoogleMaps

Paratypes: New Caledonia. Lifou Island , LIFOU cruise, Stn 1475, 20.93°S, 167.3166°E, subtidal, 11 November 2000:ten M, 1.5–3.2mm, six ov.F, 1.6–2.4 mm, one F, 2.1mm (MNHN-IU-2013-17377-17381). – Stn 1406, 20.78°S, 167.1283°E, intertidal, 18 November 2000: one M, 1.6 mm, six ov. F, 1.5–1.9 mm (MNHN-IU-2013-17367). – Stn 1426, 20.765°S, 167.1033°E, 4–7 m, 20 November 2000: one ov. F, 1.9 mm, one F, 2.0 mm (MNHN-IU-2013-17366). – Stn 1467, 20.7766°S, 167.09°E, 90 m, 20 November 2000: two ov. F, 2.3–2.4 mm (MNHN-IU-2013-17363). – Stn 1418, 20.7816°S, 167.1316°E, 1–5 m, 21 November 2000: one M, 1.7 mm, two ov. F, 1.6–1.8 mm (MNHN-IU-2013-17368). – Stn 1421, 20.8733°S, 167.1416°E, 4 m, 26 November 2000: one ov. F, 1.8 mm (MNHN-IU-2013-17365) GoogleMaps .

New Caledonia, Touho Island . 20.7833ºS, 165.2167ºE, 10 m, 7 September 1993: two M, 1.6–2.0 mm, two ov. F, 2.1–2.2 mm (MNHN-IU-2013-17364), one M, 1.8 mm (MNHN-IU-2013-17330) GoogleMaps . Vanuatu. SANTO cruise, Stn LD 10, 15.3633ºS 167.19ºE, 2–4 m, 29 September 2006: one ov. F, 2.0 mm (MNHN-IU-2013-17369) GoogleMaps .

Other material: New Caledonia, Touho Island , Stn LF 4, 20.7025°S, 167.165°E, 8 m, 28 November 1995: one M, 2.1 mm (MNHN-IU-2013-17362) GoogleMaps .

Vanuatu. SANTO cruise, Stn EP 10, 15.6333°S, 167.2267°E, 45–101 m, 15 September 2006 GoogleMaps : one M, 1.3 mm, one F, 2.0 mm (MNHN-IU-2013-17376). – Stn DB40, 15.4966°S, 167.2516°E, 5 m, 19 September 2006: two M, 1.5–1.7 mm, four ov. F, 1.6–1.8 mm (MNHN-IU-2013-17374). – Stn DB83, 15.7233°S,

Figure 8. Coralliogalathea minuta sp. nov., New Caledonia, Touho Island, male, holotype, 2.6 mm (MNHN-IU-2013-17329). A, carapace and abdomen, dorsal view. B, thoracic sternites 3 and 4. C, left part of cephalothorax, ventral view, showing antennular and antennal peduncles, and anterior part of pterygostomian flap. D, right Mxp3, lateral view. E, left P4, lateral view. Scale bar: 1 mm in A, E; 2 mm in B–D.

167.25°E, 6 m, 3 October 2006: two M, 1.2–1.6 mm, ten ov. F, 1.7–1.9 mm (MNHN-IU-2013-17370). – Stn ZR12, 15.6117°S, 167.0333°E, 2–30 m, 5 October 2006: two M, 1.8–2.1 mm, one ov. F, 1.9 mm (MNHN-IU-2013-17375). – Stn FS51, 15.7116°S, 167.2516°E, 2–3 m, 5 October 2006: two M, 1.8–1.9 mm (MNHN-IU-2013-17373). – Stn LD25, 15.5416°S, 167.175°E, 3–4 m, 7 October 2006: one ov. F, 1.8 mm (MNHN-IU-2013-17371). – Stn EP36, 15.5517°S, 167.2067°E, 20–60 m, 15 October 2006: one ov. F, 1.8 mm (MNHN-IU-2013-17372).

Etymology

From the Latin minutus, meaning small, in reference to the size of the species.

Description

Carapace: 1.0–1.1 times broader than long; cervical groove barely distinct; most ridges on gastric region interrupted or scale like; one scale-like epigastric Pterygostomian flap rugose, with one distinct spine on upper margin near linea anomurica, with sparse short setae, anterior margin bluntly angular.

Sternum: Nearly as long as broad; lateral extremities gently divergent posteriorly. Third sternite triangular, as wide as long.

Abdomen: Somites 2–3 each with two uninterrupted transverse ridges on tergite, anterior ridge slightly more elevated than posterior ridge; somite 4 with posterior ridge scale like; somites 5 and 6 smooth, posteromedian margin of somite 6 straight.

Eyes: Ocular peduncles as long as broad, maximal corneal diameter 0.7 of rostrum width.

A n t e n n u l e: A r t i cl e 1 w i t h t w o w e l l -d e v e l o p e d distodorsal and distolateral mucronated spines, distodorsal larger, with small mesial spine at base; distomesial spine small. Ultimate article without a tuft of fine setae on distodorsal margin.

Figure 9. Coralliogalathea minuta sp. nov., New Caledonia. Lifou Island, paratype, male, 2.1 mm (MNHN-IU-2013-17379). A, carapace and abdomen, dorsal view. B, right P1, dorsal view. C, left P2, lateral view. D, left P3, lateral view. E, left P4, lateral view. Scale bar: 1 mm.

ridge; two scale-like protogastric ridges, posterior ridge short, arcuate, with thick plumose setae; one mesogastric ridge, medially interrupted or scale like, not extending to anteriormost marginal branchial spines; one metagastric ridge, medially interrupted and not extending to anterior branchial ridges. Anterior branchial region with distinct ridges. Mid-transverse ridge usually uninterrupted, preceded by shallow cervical groove, followed by three transverse ridges, two of them uninterrupted. Lateral margins slightly convex medially, with five or six spines: one spine in front of and four or five spines behind anterior cervical groove; first spine anterolateral, small, at level of or slightly behind orbit, located at midlength between outer orbital spine and anteriormost spine of branchial margin; two spines on anterior branchial margin, and two or three spines on posterior branchial margin. Strong outer orbital spine. Rostrum lanceolate, slightly longer than broad, length 0.3 and breadth 0.3 that of carapace; dorsal surface concave at base; lateral margin with three incised sharp teeth, margin between proximal and median spines straight.

Antenna: Article 1 with strong distomesial spine barely reaching distal margin of article 3.

Mxp3: Ischium with minute spine on flexor distal margin. Merus as long as ischium; flexor margin with one strong spine; extensor margin with one distal spine. Carpus unarmed.

P1: Males 3.0–3.8 and females 1.7–2.5 times carapace length. Merus 0.9–1.0 length of carapace, 1.8 times as long as carpus, with some dorsomesial and a few ventromesial spines. Carpus 0.7 length of palm,1.4 times as long as broad; dorsal surface with small spines or acute granules; mesial row of strong spines, with one or two ventral spines. Palm 1.4 times as long as broad, a few acute granules along lateral and mesial margins. Fingers unarmed, 0.8 length of palm, each finger distally with two rows of teeth, spooned.

P2–4: With setose striae and some long plumose setae. P2 1.6 times carapace length. Meri successively shorter posteriorly (P3 merus 0.9 length of P2 merus, P4 merus 0.9 length of P3 merus); P2 merus 0.5–0.6 carapace length, 3.3 times as long as broad, 1.3 length of P2 propodus; P3 merus 3.2 times as long as broad, 1.3 length of P3 propodus; P4 merus 3.0 times as long as broad, 1.0–1.2 length of P4 propodus. Extensor margins of meri with row of three to five proximally diminishing small spines on P2–3, unarmed on P4; flexor margins distally ending in small spine followed proximally by several eminences; lateral sides unarmed. Carpi unarmed on extensor margin; lateral surface with several acute granules sub-paralleling extensor margin on P2–4; flexor distal margin unarmed. P2–4 propodi 4.0–4.8 times as long as broad; extensor margin unarmed; flexor margin with four slender movable spines on P2–4. Dactyli distally ending in well-curved strong spine, length 0.6 that of propodi.

Remarks

Coralliogalathea minuta is morphologically related to C. parva from Vanuatu, Papua New Guinea and the Mariana Islands and C. megalochira from French Polynesia. Coralliogalathea minuta is easily distinguished from the other species by the shapes of the rostrum and the carapace. The rostrum is lanceolate in C. minuta and spatulate in the other species, and the carapace is slightly shorter than, or as long as, it is wide in C. minuta , whereas it is clearly wider (≥ 1.2 times) than long in the other species.

Genetic divergences between C. minuta and its most similar species were, with C. parva , 13.6 and 10% for COI and 16S, respectively, and with C. megalochira , 13.9 and 9% for COI and 16S, respectively ( Table 2). The genetic distance between C. minuta and C. humilis was the lowest observed among Coralliogalathea species (see above).

Distribution New Caledonia, Vanuatu, subtidal to 101 m.

CORALLIOGALATHEA PARVA SP. NOV.

( FIG. 10)

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Material examined

Holotype: Vanuatu. Stn FB 80, 15.5516°S, 167.16°E, 2 m, 14 October 2006:M, 2.1 mm (MNHN-IU-2013-17328). GoogleMaps

Paratypes: Mariana Islands, Guam Island. Pago Bay , reef flat to crest channel, under rocks, 0–2 m, 2003: one ov. F, 2.1 mm ( UF4229 ). – Cabras, 13.4649°N, 144.6872°E, 0–4 m, 20 June 2010: one M, 2.7 mm ( UF26641 ) GoogleMaps .

Papua New Guinea, Bismark Archipelago , Tungelo Island, Mascot Channel, reef flat adjacent to channel, sand and seagrass, 2.655°S, 150.46°E, 1–2 m, 2 July 2003: one ov. F, 1.7 mm ( UF4837 ) GoogleMaps .

KAVIENG lagoon cruise, Stn KS21, 02.5667°S, 150.7667°E, 4 m, 7 June 2014: one ov. F, 1.6 mm (MNHN-IU-2014-13507). – Stn KB30, 02.7333°S, 150.65°E, 8–15 m, 11 June 2014: two M, 1.5–2 mm, (MNHN-IU-2014- 13693 -13636). – Stn KB36, 02.6333°S, 150.6333°E, 3–8 m, 13 June 2014: one M, 1.7 mm, one F, 1.5 mm (MNHN-IU-2014-13690-13665). – Stn KS41, 02.6°S, 150.5333°E, 2–7 m, 16 June 2014: one ov. F, 1.9 mm (MNHN-IU-2014-13692).

Vanuatu. SANTO cruise, Stn DB 40, 15.4967°S, 167.2517°E, 5 m, 19 September 2006: three M, 1.2 mm, six ov. F, 1.3–1.8 mm, one F, 1.3 mm (MNHN-IU-2013-17383). Stn FB 61, 15.5733°S, 167.21°E, 2–3 m, 7 October 2006: one M, 1.6 mm (MNHN-IU-2013-17382). – Stn ZB 20, 15.6016°S, 167.09°E, 15–20 m, 10 October 2006: one ov. F, 1.6 mm (MNHN-IU-2013-17386). – Stn FB 80, 15.5516°S, 167.16°E, 2 m, 14 October 2006: three M, 1.5–2.0 mm, four ov. F, 1.8–2.2 mm (MNHN-IU-2013-17326) GoogleMaps .

Other material: Vanuatu. SANTO cruise, Stn DB 12, 15.61°S, 167.1683°E, 10–18 m, 13 September 2006: one ov. F, 1.4 mm (MNHN-IU-2013-17387). – Stn EP 10, 15.6333°S, 167.2266°E, 45–101 m, 15 September 2006: one M, 1.3 mm, one F, 2.0 mm ( MNHN) – Stn DB 53, 15.48°S, 167.2533°E, 5 m, 22 September 2006: five M, 1.4– 1.7 mm, four ov. F, 1.5–1.8 mm (MNHN-IU-2013-17385). – Stn DB 67, 15.3816°S, 167.2183°E, 7 m, 26 September 2006: one M, 1.6 mm (MNHN-IU-2013-17392). – Stn DB 71, 15.36°S, 167.2083°E, 7 m, 27 September 2006: one M, 1.7 mm, two ov. F, 1.6–1.8 mm, one F, 1.4 mm (MNHN-IU-2013-17390). – Stn NS 36, 15.5283°S, 167.1583°E, 2–3 m, 2 October 2006: one M, 1.8 mm (MNHN-IU-2013-17389). – Stn DB 83, 15.7233°S, 167.25°E, 6 m, 3 October 2006: three M, 1.2–1.6 mm, ten ov. F, 1.7–1.9 mm ( MNHN). – Stn FB 52, 15.7116°S, 167.2516°E, 7 m, 5 October 2006: six M, 1.4–1.6 mm; eight ov. F, 1.3–1.6 mm (MNHN-IU-2013-17388). – Stn FB 92, 15.56°S, 167.2766°E, 2–4 m, 14 October 2006: one M, 1.7 mm, two ov. F, 1.6–1.8 mm (MNHN-IU-2013-17393). – Stn FS 79, 15.5516°S, 167.16°E, 2 m, 14 October 2006: one M, 1.4 mm, one F, 1.4 mm (MNHN-IU-2013-17391). – Stn FB 80, 15.5516°S, 167.16°E, 2 m, 14 October 2006: 11 M, 1.3–2.4 mm, 13 ov. F, 1.6–2.3 mm (MNHN-IU-2013-17384). – Stn LD 35, 15.5466°S, 167.1933°E, 3–8 m, 16 October 2006: one M, 1.3 mm (MNHN-IU-2013-17394) GoogleMaps .

Etymology

From the Latin parvus, meaning little, in reference to the small size of the species.

Description

Carapace: 1.2–1.3 times broader than long; cervical groove barely distinct; most ridges on gastric region interrupted or scale-like; one scale-like epigastric ridge; two scale-like protogastric ridges 1.2–1.3 times broader than long, posterior ridge short, arcuate, with thick plumose setae; one mesogastric ridge, medially interrupted or scale like, not extending to anteriormost marginal branchial spines; one metagastric ridge, uninterrupted and not extending to anterior branchial ridges. Anterior branchial region with distinct ridges. Mid-transverse ridge usually uninterrupted, preceded by shallow cervical groove, followed by three transverse ridges, two of them uninterrupted. Lateral margins slightly convex medially, with five or six spines: one spine in front of and four or five spines behind anterior cervical groove; first spine anterolateral, small, at level of orbit, located at midlength between outer orbital spine and anteriormost spine of branchial margin; two spines on anterior branchial margin, and two or three spines on posterior branchial margin. Strong outer orbital spine; infraorbital margin with two strong spines. Rostrum spatulate, slightly longer than broad, length 0.4 and breadth 0.3 that of carapace; dorsal surface concave at base; lateral margin with three incised sharp teeth, margin between proximal and median spine clearly convex.

Pterygostomian flap rugose, with one distinct spine on upper margin near linea anomurica, with sparse short setae, anterior margin bluntly angular.

Sternum: Nearly as long as broad; lateral extremities gently divergent posteriorly. Third sternite triangular, longer than wide.

Abdomen: Somites 2–3 each with two uninterrupted transverse ridges on tergite, anterior ridge slightly more elevated than posterior ridge; somite 4 smooth or with posterior scale-like ridge; somites 5 and 6 smooth, posteromedian margin of somite 6 straight.

Eyes: Ocular peduncles as long as broad, maximal corneal diameter 0.7 of rostrum width.

A n t e n n u l e: A r t i cl e 1 w i t h t w o w e l l -d e v e l o p e d distodorsal and distolateral mucronated spines, distodorsal larger. Ultimate article without a tuft of fine setae on distodorsal margin.

Antenna: Article 1 with strong distomesial spine barely reaching distal margin of article 3.

Mxp3: Ischium with minute spine on flexor distal margin. Merus as long as ischium; flexor margin with one strong spine; extensor margin with one distal spine. Carpus unarmed.

P1: Males 2.7–3.1 and females 1.8–1.9 times carapace length. Merus 0.8–0.9 length of carapace, 1.5 times as long as carpus, with some dorsomesial and a few ventromesial spines. Carpus 1.0–1.2 length of palm, 1.7–1.8 times as long as broad; dorsal surface with small spines or acute granules; mesial row of spines, median and distal spines strong. Palm 1.2 times as long as broad, a few acute granules along lateral and mesial margins. Fingers unarmed, 1.2 length of palm, each finger distally with two rows of teeth, spooned.

P2–4: With setose striae and some long plumose setae. P2 1.7 times carapace length. Meri successively shorter posteriorly (P3 merus 0.9 length of P2 merus; P4 merus 0.9–1.0 length of P3 merus); P2 merus 0.6 carapace length, 3.0 times as long as broad, 1.0–1.1 length of P2 propodus; P3 merus 2.5 times as long as broad, 1.1–1.2 length of P3 propodus; P4 merus 2.7 times as long as broad, 1.1–1.3 length of P4 propodus. Extensor margins of meri with row of three or four proximally diminishing small spines on P2–3, unarmed on P4; flexor margins distally ending in small spine followed proximally by several eminences; lateral sides unarmed. Carpi unarmed or with one or two minute spines on extensor margin; lateral surface with several acute granules sub-paralleling extensor margin on P2–4; flexor distal margin unarmed. P2–4 propodi 5.0–6.5 times as long as broad; extensor margin unarmed; flexor margin with four slender, movable spines on P2–4. Dactyli distally ending in well-curved strong spine, length 0.6 that of propodi.

Remarks

C o r a l l i o g a l a t h e a p a r v a i s c l o s e l y r e l a t e d t o C. megalochira from French Polynesia (see the differences under the Remarks for C. megalochira ). These species also presented the lowest genetic divergence among the species of Coralliogalathea (6.7% for COI and 2.4% for 16S). Average mean intraspecific distances were 1.3 and 0.6% for COI and 16S, respectively ( Table 2).

Distribution

Mariana Islands, Papua New Guinea, Vanuatu, under rocks, sand and seagrass, 0–20 m.

CORALLIOGALATHEA TRIDENTIROSTRIS ( MIYAKE,