Phylladiorhynchus punctatus, 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 : 126-128

Phylladiorhynchus punctatus n. sp.

( Figs. 48 , 50G , 56B )

Type material. Holotype. New Caledonia, LIFOU Stn 1648, 20.9017°S, 167.0550°E, 150–200 m, 7 November 2000: ov. F 2.8 mm (MNHN-IU-2014-13844).

Paratypes. New Caledonia. LIFOU Stn 1647, 20.70750°S, 167.1333°E, 150–200 m, 6 November 2000: 1 M 3.2 mm (MNHN-IU-2014-13845).— Stn 1648, 20.9017°S, 167.0550°E, 150–200 m, 7 November 2000: 1 F 1.8 mm (MNHN-IU-2014-13843) .

New Caledonia. Koumac 2.3 Stn KL 17, 20.55685°S, 164.0732667°E, 92 m, 14 November 2019: 1 M 1.7 mm (MNHN-IU-2014-20101) .

Etymology. From the Latin punctum, spot, in reference of the red spots covering the pleonal tergites of this species.

Description. Carapace: As long as broad, transverse ridges with few short setae. Gastric region flattened, with 4 transverse ridges: epigastric ridge indistinct, with 5 spines (1 median and 2 pairs of spines laterally); anterior protogastric ridge not medially interrupted, laterally interrupted with few scales; anterior mesogastric ridge scalelike (with 1 to 3 scales), laterally interrupted by anterior branch of cervical groove, laterally continuing uninterrupted to first branchial spine; anterior metagastric ridge scale-like and followed by few scales on posterior metagastric area. Mid-transverse ridge not interrupted, medially depressed, preceded by a distinct cervical groove, followed by 2 uninterrupted or minutely interrupted ridges, interspersed with 1 short lateral ridge and few short, scattered scales. Lateral margins straight or slightly convex, with 6 spines: first anterolateral spine well-developed, reaching end of lateral orbital spine, second spine (hepatic) well-developed, slightly dorsomesially from lateral margin, and followed by 4 branchial spines (2 anterior and 2 posterior). Rostrum triangular, horizontal, dorsally flattish or slightly concave, 1.4–[1.6] × as long as broad, length [0.4]0.4 and breadth [0.3]0.3 that of carapace; lateral margins smooth and straight, with well-developed supraocular spines, subapical spines absent. Pterygostomian flap ending in small spine, upper margin smooth.

Thoracic sternum: As wide as long. Sternite 3 sharply broad, [3.4]3.3–4.0 × as wide as long, anterior margin straight or moderately convex, with a median deep notch, moderately produced anterolaterally. Sternite 4 widely contiguous to sternite 3; surface depressed in midline, smooth; greatest width 1.5–[2.4] × that of sternite 3, [3.3]–4.2 × as wide as long.

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

Eye: Eyestalk length about 1.3 × broader than long, peduncle distally setose, not distinctly expanded proximally; maximum corneal diameter 1.0 × rostrum width, as wide as eyestalk.

Antennule: Article 1 1.3 × longer than wide, with 5 spines: distomesial spine small; proximal lateral spine well developed, always present.

Antenna: Article 1 with prominent mesial process, distally not reaching lateralmost antennular spine. Article 2 with small distomesial and distolateral spines. Articles 3 and 4 unarmed.

Mxp3: Ischium with distinct distal spines on flexor and extensor margins. Merus 0.5 × length of ischium, with well-developed distal spine on extensor margin and 2 strong spines on flexor margin.

P1 (lost in holotype and in males): 3.5 (females) × carapace length; subcylindrical, spiny and with scattered long stiff setae; merus, carpus and palm with spines along mesial, dorsal and lateral surfaces, distal and mesial spines usually stronger than others. Merus 1.4 length of carapace, 2.0–2.5 × as long as carpus. Carpus 2.5–2.9 × as long as wide. Palm 1.1× carpus length, 2.2–3.5 × as long as broad. Fingers subequal in length to palm; fixed finger unarmed; movable finger with well-developed basal spine.

P2–4: Slender, subcylindrical, moderately setose and spinose. Meri successively shorter posteriorly: P3 merus 0.9–[1.0] × length of P2 merus, P4 merus 0.9 × length of P3 merus. P2 merus, [0.7]0.8 × carapace length, [6.0]–8.0 × as long as broad, [1.0]–1.3 × as long as P2 propodus; P3 merus [6.0]–7.0 × as long as broad, 1.0 × as long as P3 propodus; P4 merus 4.5–[5.5] × as long as broad, 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, with small distal spine; flexor margins of P2–4 irregular, each with distal spine; P4 lateral surface with median row of 3 small spines, absent in P2–3. Carpi with 3 or 4 spines on extensor margin on P2–3, unarmed on P4; distal spine prominent on P2–3, smaller on P4; row of small spines below extensor margin on lateral surface of P2–3, unarmed on P4; flexor margins on P2-4 with distal spine. Propodi slender, 7.0–[9.0] × as long as broad; extensor margin usually armed with 1–2 small spines on proximal half of P2–4; flexor margin with 4 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 6–7 movable spines.

Live colour. Body light orange; carapacecovered by orange and golden-yellow spots. Pleonal tergites 1–4 light orange; tergites 3–4 each with two symmetrical vertical white stripes and 2 red spots. P2–4 clear with distinct red bars.

Genetic data. COI and 16S, Table 1.

Distribution. New Caledonia and Chesterfield Islands, from 92 to 200 m.

Remarks. Phylladiorhynchus punctatus belongs to the group of species having 5 epigastric spines, 2 spines on the anterior branchial margin and the Mxp3 merus with 2 prominent spines along the flexor margin. Phylladiorhynchus punctatus resembles P. kermadecensis Schnabel & Ahyong, 2019 from New Zealand, but they can be distinguished by the following characters:

- The rostral margins are slightly concave in P. kermadecensis , whereas these margins are straight in P. punctatus .

- The anterior mesogastric ridge is scale-like in P. punctatus , whereas this ridge is not medially interrupted in P. kermadecensis .

- The anterior metagastric ridge is not medially interrupted in P. punctatus , whereas it is medially interrupted in P. kermadecensis .

The sequences of P. punctatus were 17% (COI) and 7% (16S) divergent from P. kermadecensis . The specimens of P. punctatus range in size from 1.7 to 3.2 mm postorbital carapace length.

Figures

FIGURE 48. Phylladiorhynchus punctatus n. sp., holotype ovigerous female 2.8 mm (MNHN-IU-2014-13844); E, paratype male 3.2 mm (MNHN-IU-2014-13845):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, left P3, lateral view. H, dactylus of right P2, lateral view. Scale bar: A, F–G = 1.0 mm; E = 1.3 mm; B–D, H = 0.6 mm.

FIGURE 50. Rostrum, dorsal view. A, Phylladiorhynchus phlias n. sp., paratype male 1.4 mm (MNHN-IU-2014-13881). B, P. poeas n. sp., paratype male 3.3 mm (MNHN-IU-2014-13737). C, P. pollux n. sp., holotype ovigerous female 3.5 mm (MNHN-IU-2014-13797). D, P. porteri n. sp., paratype female 2.4 mm (MNHN-IU-2014-23831). E, P. priasus n. sp., paratype ovigerous female 2.1 mm (UF54422). F, P. pulchrus n. sp., paratype male 1.8 mm (MNHN-IU-2019-2675). G, P. punctatus n. sp., paratype male 1.7 mm (MNHN-IU-2019-20101). H, P. serrirostris (Melin, 1939), paralectotype male 2.3 mm (UPSTY2531). I, P. spinosus Schnabel & Ahyong, 2019, male 3.3 mm (MNHN-IU-2016-492). J, P. talaus n. sp., paratype ovigerous female 2.4 mm (WAM C43997). K, P. tiphys n. sp., holotype male 2.4 mm (MNHN-IU-2014-13794). L, P. zetes n. sp., holotype male 2.1 mm (UF30059). Scale bars: 1 mm.

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.