Phylladiorhynchus gustavi, Rodríguez-Flores & Macpherson & Machordom, 2021

Rodríguez-Flores, Paula C., Macpherson, Enrique & Machordom, Annie, 2021, Revision of the squat lobsters of the genus Phylladiorhynchus Baba, 1969 (Crustacea, Decapoda, Galatheidae) with the description of 41 new species, Zootaxa 5008 (1), pp. 1-159 : 41-42

Phylladiorhynchus gustavi n. sp.

( Figs. 14 , 21B , 27A–B , 54D )

Type material. Holotype. French Polynesia. Society Islands , Moorea Island, NE of Tareu Pass, 17.4836°S, 149.8581°W, 22 m, 24 July 2006: ov. F 2.2 ( UF9766 ).

Paratypes. Cook Islands. Rarotonga Island , Matavera, 21.226°S, 159.7293°W, 9–24 m, 26 June 2006: 1 ov. F 2.0 mm ( UF9232 ) .

French Polynesia. Society Islands. Moorea Is. 17.506°S, 149.759°W, 15–22 m, 27 May 2006: 1 ov. F 1.8 mm ( UF9471 ) , 1 ov. F 2.0 ( UF9603 ) .— 17.4836°S, 149.8581°W, 22 m, 24 July 2006: 1 M 1.7 ( UF9756 ) .— 17.4768°S, 149.8327°W, 5 August 2006: 2 M 1.0– 2.2 mm, 1 ov. F 2.1 mm ( UF14832 ) .— 17.4764°S, 149.8327°W, 4–7 m, 10 November 2008: 1 M 2.3 mm ( UF16338 ) , 1 ov. F 2.3 mm ( UF16370 ) , 1 M 2.4 mm, 1 ov. F 2.1 mm, 1 F 1.7 mm ( UF18384 ) , 1 M 2.4 mm ( UF16399 ) .— French Polynesia. BENTHAUS Stn DW1926, 24.6360°S, 146.0136°W, 50–90 m, 13 November 2002: 1 M 2.2 mm, 1 ov. F 2.6 mm (MNHN- IU-2019-2592) .

Other material. French Polynesia. Society Islands. Moorea Is. Maharepa , 2 m, 11 October 2008: 1 ov. F 2.3 mm ( UF15431 ) .— on Pocillopora , June 2009: 1 M 2.0 mm ( UF37850 ) .— 17.484°S, 149.9264°W, 19–20 m, 3 November 2009: 1 M 1.8 mm ( UF23879 ) .— 17.4756°S, 149.8425°E, 13–17 m, 5 December 2009: 1 ov. F 2.2 mm ( UF24183 ) .— 17.4764°S, 149.8316°W, 13 m, 31 January 2012: 4 M 1.4–2.1 mm, 9 ov. F 1.7–2.1 mm, 2 F 1.2–1.9 mm ( UF33774 ) .— 17.4759°S, 149.8419°W, 13 m, 4 February 2012: 10 M 1.4–2.3 mm, 9 ov. F 1.6–2.3 mm, 1 F 1.9 mm ( UF33968 ) , 1 F 2.2 mm ( UF33966 ) , 1 M 2.0 mm ( UF33967 ) . Gambier Islands. Totegegie Airport , 23.0776°S, 134.8884°W, 22.5 m, 6 February 2013: 1 ov. F 2.3 mm ( UF35486 ) , 1 M 2.2 mm ( UF35473 ) , 1 F 1.8 mm ( UF35479 ) , 1 ov. F 2.5 mm ( UF35481 ) , 1 M 2.3 mm ( UF35485 ) .

Etymology. The new species is named after our colleague Gustav Paulay from the Florida Museum of Natural History for his valuable contribution to marine research.

Description. Carapace: Slightly broader than long; transverse ridges with dense short setae and long and thick iridescent setae. Gastric region slightly convex with some transverse ridges: epigastric ridge distinct with 2 spines, short scales laterally; anterior protogastric ridge not medially interrupted, nearly extending laterally to carapace margin, sometimes followed by small scales; anterior mesogastric ridge not medially interrupted, laterally continuing to first branchial spine, sometimes followed by some short lateral scales; anterior metagastric ridge scalelike, often followed by some short small median scale posteriorly. Mid-transverse ridge not interrupted, medially depressed, cervical groove indistinct, followed by 2 not interrupted or minutely interrupted ridges, interspersed with 1 short lateral ridge and few short scales. Lateral margins slightly convex, with 6–7 distinct spines: first anterolateral spine well-developed, reaching anteriorly to level of lateral orbital spine, second spine (hepatic) small, slightly dorsomesially from lateral margin, and followed by 5 branchial spines (3 anterior and 1–2 posterior). Rostrum leaf-like, horizontal, dorsally concave, [1.1]–1.4 × as long as broad, length [0.3]–0.4 and breadth 0.2–[0.3] that of carapace; lateral margins serrated and strongly convex, with well-developed supraocular basal spines and small subapical spines (tridentiform). Pterygostomian flap ending in blunt tooth, upper margin smooth.

Thoracic sternum: As wide as long. Sternite 3 moderately broad, 1.8–[1.9] × as wide as long, anterior margin serrated and convex, anterolaterally rounded. Sternite 4 widely contiguous to sternite 3; anterolaterally serrated, surface depressed in midline, smooth; greatest width [3.3] × that of sternite 3, [2.5] × as wide as long.

Pleon: Elevated ridges with short setae and a few scattered long setae. Tergites 2–3 with anterior and posterior transverse elevated ridges; tergite 4 with anterior transverse ridge only; tergites 5–6 smooth.

Eye: Eyestalk length about 1.0–[1.1] × broader than long, peduncle distally setose, not distinctly expanded proximally; cornea expanded distally, maximum corneal diameter [0.6]–0.7 × rostrum width, narrower than eyestalk (0.8–0.9 maximum peduncle width).

Antennule: Article 1 slightly longer than wide, with 4 distal spines: distomesial spine well-developed; proximal lateral spine always absent.

Antenna: Article 1 with prominent mesial process distally falling well short or overreaching lateralmost antennular spine. Article 2 with well-developed distomesial and distolateral spines. Article 3 with distomesial spine. Article 4 unarmed.

Mxp3: Ischium with distinct distal spines on flexor and extensor margins. Merus 0.7–[0.8] × length of ischium, with well-developed distal spine on extensor and flexor margins.

P1: [2.8]–3.0 (males), 1.9–2.0 (females) × carapace length; subcylindrical, spiny and with long stiff setae and iridescent setae; merus, carpus and palm with spines along mesial, dorsal and lateral surfaces, distal and mesial spines usually stronger than others. Merus 0.7–[1.0] length of carapace, [1.6]–1.9 × as long as carpus. Carpus [1.5]–1.7 × as long as wide. Palm [1.1]–1.2 × carpus length, [1.5]–1.6 × as long as broad. Fingers 0.8 × palm length fixed finger with 2 small basal spines, movable finger with basal spine or unarmed.

P2–4: Stout, setose, with iridiscent setae, and spinose. Meri successively shorter posteriorly: P3 merus 0.9 × length of P2 merus, P4 merus [0.8]–0.9 × length of P3 merus. P2 merus, [0.7]–0.9 × carapace length, 3.1–[3.4] × as long as broad, 1.1–[1.2] × as long as P2 propodus; P3 merus 3.4–[3.8] × as long as broad, 1.1–[1.2] × as long as P3 propodus; P4 merus 3.2 × as long as broad, 1.0–1.1 × as long as P4 propodus; extensor margin of P2 and P3 with row of spines, proximally diminishing, with prominent distal spine; P4 extensor margin irregular, unarmed; flexor margin irregular, with distal spine on P2–3, distal spine absent in P4. Carpi with 1–3 spines on extensor margin on P2–3, unarmed on P4; distal spine prominent on P2–3, smaller on P4; granules below extensor margin on lateral surface of P2–4; flexor margin unarmed. Propodi stout, [4.0]3.6–4.3 × as long as broad; extensor margin irregular, armed with 2–4 spines; flexor margin with 3–6 slender movable spines in addition to distal pair. Dactyli [0.6]–0.7 × length of propodi, ending in incurved, strong, sharp spine; flexor margin with 5–6 movable spines.

Eggs: Ov. F carried approximately 8– 20 eggs of 0.4–0.6 mm diameter.

Live colour. Base colour of carapace and pleon whitish or beige, with small brownish patches. P1 whitish or beige with scattered brownish spots. P2–4 whitish, with brown bandings.

Genetic data. COI, Table 1.

Distribution. French Polynesia, Society Islands and Cook Islands, between 2 and 90 m.

Remarks. Phylladiorhynchus gustavi belongs to the group of species having 2 epigastric spines, 1 hepatic spine and 3 spines on anterior branchial margin. The specimens range from 1.2 to 2.6 mm postorbital carapace length. The closest species is P. laureae , from from Japan, Mariana Islands, American Samoa, Papua New Guinea, Vanuatu and New Caledonia (see the differences under the Remarks of that species). The two sequences of P. gustavi from French Polynesia diverged 0.4% for COI.

Figures

FIGURE 14. Phylladiorhynchus gustavi n. sp., holotype ovigerous female 2.2 mm (UF9766): A, carapace and pleon, dorsal view. B, thoracic sternites 3 and 4. C, left cephalic region, showing antennular and antennal peduncles, ventral view. D, right Mxp3, lateral view. E, left P1, dorsal view. F, left P2, lateral view. G, right P3, lateral view. H, dactylus of left P2, lateral view. Scale bar: A, E–G = 1.0 mm; B–D, H = 0.6 mm.

FIGURE 21. Rostrum, dorsal view. A, Phylladiorhynchus euryalus n. sp., paratype male 1.8 mm (UF34732). B, P. gustavi n. sp., paratype male 1.7 mm (UF9756). C, P. heptacanthus n. sp., holotype female 2.1 mm (MNHN-IU-2017-2534). D, P. hylas n. sp., paratype female 1.6 mm (MNHN-IU-2016-495). E, P. integrirostris (Dana, 1852), male 1.6 mm (UF15285). F, P. integrus (Benedict, 1902), ovigerous female 3.2 mm (MNHN-IU-2014-13853). G, P. iphiclus n. sp., holotype ovigerous female 2.3 mm (MNHN-IU-2019-2662). H, P. janiqueae n. sp., paratype male 1.8 mm (MNHN-IU-2016-482). I, P. jeffkinchi n. sp., paratype male 2.7 mm (MNHN-IU-2014-13565). J, P. joannotae n. sp., paratype male 2.1 mm (MNHN-IU-2014-20055). K, P. joannotae n. sp., holotype ovigerous female 2.1 mm (MNHN-IU-2014-13805). L, P. koumac n. sp., paratype male 1.5 mm (MNHN-IU- 2014-20121). Scale bars: 1 mm.

FIGURE 27. A–C, Carapace, dorsal view; B–D, rostrum, dorsal view. A–B, Phylladiorhynchus gustavi n. sp., paratype male 2.0 mm (UF33968). C-D, Phylladiorhynchus laureae n. sp., paratype ovigerous female 2.0 mm (UF54543). Scale bars: A, C = 1 mm, B, D = 0.5 mm.

FIGURE 54. Colour in life, dorsal view. A. Phylladiorhynchus acastus n. sp. Papua New Guinea, male 2.5 mm (MNHN-IU- 2014-10017). B, Phylladiorhynhus barbeae n. sp. Papua New Guinea, paratype male 1.6 mm (MNHN-IU-2014-13810). C, Phylladiorhynhus barbeae n. sp. Papua New Guinea, male 2.5 mm (MNHN-IU-2014-13813). D, Phylladiorhynchus gustavi n. sp. French Polynesia, male 2.3 mm (UF16338). E, Phylladiorhynchus janiqueae n. sp. Walter shoal, male 1.8 mm (MNHN-IU- 2014-13840). F, Phylladiorhynchus jeffkinchi n. sp. Papua New Guinea, ovigerous female 2.2 mm (MNHN-IU-2014-2176). G, Phylladiorhynchus joannotae n. sp. French Polynesia, ovigerous female 2.2 mm (UF15544). H, Phylladiorhynchus joannotae n. sp. New Caledonia, female 1.0 mm (MNHN-IU-2014-20147). I, Phylladiorhynchus koumac n. sp. New Caledonia, male 1.5 mm (MNHN-IU-2014-20121).