Phylladiorhynchus lini, 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 : 80-83

Phylladiorhynchus lini n. sp.

( Figs. 29 , 30J–L, S–T , 33B , 55A , 56D–I )

Type material. Holotype. Taiwan, Kenting County, Houbihu , 21.936361°N, 120.746806°E, 7–10 m, 2 June 2019: F 2.2 mm ( NMMBCD5596 ).

Paratypes. Taiwan. Kenting County. Small fishing port S of Wanlitung. 21.9706°N 120.7156°E, 5–8 m, 30 June 2007: 1 ov. F 2.6 ( UF11812 ) .— Kenting County, National Museum of Marine Biology & Aquarium, Water outlet , 21.9319°N, 120.7344°E, 8–10 m, 23 May 2011: 1 M 3.4 mm ( NMMBCD) .— 21.9319°N, 120.7344°E, 8–10 m, 24 May 2011: 1 ov. F 3.0 mm, 1 F 3.2 mm ( NMMBCD) .— 21.9230°N, 120.8319°E, 7–10 m, 30 May 2011: 9 M 2.6–3.7 mm, 2 F 2.9–3.2 mm, 9 ov. F 1.7–3.1 mm ( NMMBCD) .— 21.9319°N, 120.7447°E, 8–10 m, 25 July 2011: 2 M 3.0– 3.1 mm, 1 ov. F 2.1 mm ( NMMBCD) .— 21.9319°N, 120.7447°E, 8–10 m, 5 October 2011: 2 F 2.5–3.1 mm ( NMMBCD) .— Houbihu , 21.9361°N, 120.7466°E, 7–10 m, 2 June 2019: 1 M 1.7 mm, 1 ov. F 2.5 mm, 1 F 1.4 mm (MNHN- IU-2016-1490).

Other material. Kenting County, National Museum of Marine Biology & Aquarium, Water outlet, 21.9319°N, 120.7447°E, 8–10 m, 13 October 2011: 1 M 2.2 mm ( NMMBCD) .— 21.9319°N, 120.7447°E, 8–10 m, 19 November 2011: 1 F 2.6 mm ( NMMBCD) .— 21.9319°N, 120.7447°E, 8–10 m, 3 May 2012: 1 ov. F 3.0 mm ( NMMBCD) .— Houbihu , 21.9361°N, 120.7466°E, 7–10 m, 14 May 2012: 1 ov. F 2.9 mm ( NMMBCD) .— Houbihu , 21.9361°N, 120.7466°E, 7–10 m, 29 June 2013: 1 ov. F 2.5 mm ( NMMBCD) .— Hojie , 21.9553°N, 120.7116°E, 24–26 m, 26 February 2013: 1 ov. F 2.7 mm ( NMMBCD) .

Etymology. The species is named after our colleague Chia-Wei Lin, from the National museum of marine biology & aquarium, Pingtung, Taiwan, who collected most of the specimens.

Description. Carapace: As long as or slightly longer than broad; transverse ridges with dense short setae and some thick setae. Gastric region slightly convex with some transverse ridges: epigastric ridge distinct with 2 median spines and some lateral short scales, followed by small short scales on posterior epigastric region; anterior protogastric ridge not medially interrupted, nearly extending laterally to carapace margin, often followed by uninterrupted posterior protogastric ridge or short scales; anterior mesogastric ridge not medially interrupted, laterally interrupted by anterior branch of cervical groove, and continuing uninterrupted to first branchial spine; anterior metagastric ridge not medially interrupted, followed by posterior scale-like metagastric ridge. Mid-transverse ridge not interrupted, medially depressed, followed by shallow or indistinct cervical groove, followed by 2–3 not interrupted or minutely interrupted ridges, interspersed with 2 interrupted riges and few short scales. Lateral margins slightly convex, with 6 distinct spines: first anterolateral spine well-developed, reaching anteriorly to level of lateral orbital spine, second spine (hepatic) well-developed, slightly dorsomesially from lateral margin, and followed by 4 branchial spines (3 anterior and 1 posterior). Rostrum dagger-like, horizontal dorsally flattish or slighly concave [1.5]–1.8 × as long as broad, length [0.4]–0.5 and breadth 0.2–[0.3] that of carapace; lateral margins smooth and straight or nearly straight, with well-developed supraocular basal spines and subapical spines. Pterygostomian flap with anterior spine, upper margin smooth.

Thoracic sternum: As wide as long. Sternite 3 moderately broad, [1.9]–2.3 × as wide as long, anterior margin convex, with a blunted median projection, anterolaterally rounded. Sternite 4 widely contiguous to sternite 3; anterolaterally smooth, surface depressed in midline, smooth; greatest width [2.5]–2.9 × that of sternite 3, 2.7–[3.5] × as wide as long.

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

Eye: Eyestalk length about 0.9–[1.1] × broader than long, peduncle distally setose, not distinctly expanded proximally, with few short transverse striae on lateral surfaces; cornea expanded distally, maximum corneal diameter [0.9]–1.0 × rostrum width, as wide as eyestalk.

Antennule: Article 1 longer than wide, with 5 distal spines: distomesial spine well-developed; proximal lateral spine small, always present.

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

Mxp3: Ischium with distinct distal spines on flexor and extensor margins. Merus [0.6]–0.7 × length of ischium, with well-developed distal spine on extensor and flexor margins.

P1: Slender, 3.0 (males), 2.0–[2.3] (females) × carapace length; subcylindrical, spiny and with long stiff setae; merus, carpus and palm with spines along mesial, dorsal and lateral surfaces, distal and mesial spines usually stronger than others. Merus 0.7–[0.9] length of carapace, 1.5–[1.8] × as long as carpus. Carpus [2.5]–3.1 × as long as wide. Palm 1.1 × carpus length, 2.3–[2.7] × as long as broad. Fingers 0.7× palm length; fixed finger with 0–1 basal spines; movable finger with 1 basal spine.

P2–4: setose 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, 1.5–[1.8] × carapace length, [3.4]–4.4 × as long as broad, [1.1]1.1 × as long as P2 propodus; P3 merus [3.6]–3.7 × as long as broad, 1.0–[1.2] × as long as P3 propodus; P4 merus [3.2]–3.7 × 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, absent or small on P4. Carpi with 2–4 small spines on extensor margin on P2–3, unarmed on P4; distal spine prominent on P2–3, absent on P4; row of granules below extensor margin on lateral surface of P2–4; flexor margin unarmed. Propodi stout, 4.0–5.0 × as long as broad; extensor margin irregular; flexor margin with 3–6 slender movable spines in addition to distal pair. Dactyli [0.6–0.7]0.5–0.7 × length of propodi, ending in incurved, strong, sharp spine; flexor margin with cuticular spines at basis of 5–6 movable spines.

Eggs: Ov. F carried approximately 4– 15 eggs of 0.5 mm diameter.

Live colour. Variable colour pattern. Body dark to light brown, sometimes orange or with large whitish spots and bands. P1–4 with dusky and whitish bands.

Genetic data. COI and 16S, Table 1.

Distribution. Taiwan, Kenting, between 5 and 26 m.

Remarks. Phylladiorhynchus lini belongs to the group of species having 2 epigastric spines, 1 hepatic spine, 3 spines on the anterior branchial margin, rostrum dagger-like (margin straights or nearly straight) and dactylar spines along the flexor margin of the P2–4 dactyli. The new species is closely related to P. spinosus Schnabel & Ahyong, 2019 , from New Zealand and Australia (see the differences under the Remarks of P. spinosus ). The specimens of P. lini range from 1.4 to 3.4 mm postorbital carapace length. The two sequences of P. lini from Taiwan diverged 0.6% (COI) and 0.2% (16S).

Figures

FIGURE 29. Phylladiorhynchus lini n. sp., holotype female 2.2 mm (NMMBCD5596): 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, right P1, dorsal view. F, right P2, lateral view. G, right P3, lateral view. H, left P4, lateral view. I, dactylus of right P2, lateral view. Scale bar: A, E–H = 1.0 mm; B–D, I = 0.6 mm.

FIGURE 30. Variability in the armature of the antennal articles 2-4 (A-L) and in the shape of the thoracic sternite 3 (M-T). P. euryalus n. sp.: A, M, paratype male 1.8 mm (UF34732); B, paratype male 1.6 mm (UF25216); C, N, paratype female 3.5 mm (MNHN-IU-2016-489). P. spinosus Schnabel & Ahyong, 2019: D, O, male 2.7 mm (MNHN-IU-2016-491); E, male 2.6 mm (MNHN-IU-2013-9439); F, P, male 2.5 mm (MNHN-IU-2016-470). P. asclepius n. sp.: G, Q, holotype male 2.1 mm (UF22296); H, R, paratype ovigerous female 2.1 mm (UF27601); I, paratype male 2.4 mm (UF27886). P. lini n. sp.: J, S, paratype ovigerous female 2.6 mm (UF11812); K, T, paratype ovigerous female 2.5 mm (MNHN-IU-2016-490); L, paratype male 1.7 mm (MNHN- IU-2016-1490). Scale bar: 1 mm.

FIGURE 33. Rostrum, dorsal view. A, Phylladiorhynchus laureae n. sp., paratype female 1.7 mm (MNHN-IU-2019-2635). B, P. lini n. sp., holotype female 2.2 mm. C, P. lynceus n. sp., holotype ovigerous female 2.0 mm (MNHN-IU-2019-2593). D, P. marina n. sp., male 1.5 mm (MNHN-IU-2019-2653). E, P. medea n. sp., paratype male 2.1 mm (MNHN-IU-2014-13795). F, P. nudus Macpherson, 2008, ovigerous female 2.4 mm (WAM C46587). G, P. nui Schnabel & Ahyong, 2019, male 6.5 mm (MNHN-IU-2019-2595). H, P. orpheus n. sp., paratype male 1.9 mm (UF33962). I, P. paula n. sp., paratype male 2.3 mm (MNHN-IU-2019-2699). J, P. penelos n. sp., paratype male 3.3 mm (UF1224). K, P. pepei n. sp., holotype male 3,2 mm (MNHN-IU-2016-486). L, P. phanus n. sp., paratype male 2.1 mm (MNHN-IU-2019-2687). Scale bars = 1 mm.

FIGURE 55. Colour in life, dorsal view.A, Phylladiorhynchus lini n. sp. Taiwan, holotype female 2.2 mm (NMMBCD5596). B, Phylladiorhynchus marina n. sp. Vanuatu, ovigerous female 2.0 mm (MNHN-IU-2014-13887). C, Phylladiorhynchus medea n. sp. New Caledonia, female 1.9 mm (MNHN-IU-2014-20063). D, Phylladiorhynchus orpheus n. sp. French Polynesia, ovigerous female 2.0 mm (UF9732). E, Phylladiorhynchus paula n. sp. îles de Mayotte. des Glorieuses et des Comores, female 3.3 mm (MNHN-IU-2016-7003). F, Phylladiorhynchus peneleos n. sp. French Polynesia, male 2.0 mm (UF16078). G, Phylladiorhynhus pepei n. sp. Madagascar, male 3.2 mm (MNHN-IU-2016-486). H, Phylladiorhynchus phanus n. sp. Papua New Guinea, ovigerous female 2.5 mm (MNHN-IU-2014-2893). I. Phylladiorhynchus phlias n. sp. Papua New Guinea, ovigerous female 1.3 mm (MNHN-IU-2013-703).

FIGURE 56. Colour in life, dorsal view. A, Phylladiorhynchus poeas n. sp. French Polynesia, male 2.5 mm (MNHN-IU-2014- 13859). B, Phylladiorhynchus punctatus n. sp. New Caledonia, male 1.7 mm (MNHN-IU-2014-20101). C, Phylladiorhynchus zetes n. sp., French Polynesia, ovigerous female 1.5 mm (UF33536). Colour variability. Phylladiorhynchus lini n. sp. Taiwan. D, paratype ovigerous female 2.5 mm (MNHN-IU-2016-1490). E, paratype ovigerous female 2.7 mm. F, paratype male 2.2 mm. G, paratype ovigerous female 3.0 mm. H, paratype ovigerous female 2.5 mm. I, paratype male 3.0 mm.