Phylladiorhynchus jeffkinchi, 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 : 62-64

Phylladiorhynchus jeffkinchi n. sp.

( Figs. 21I , 23 , 54F )

Type material. Holotype. Papua New Guinea, KAVIENG Stn KS 31, 02.6583°S, 150.6283°E, 15 m, 12 June 2014: ov. F 2.4 mm (MNHN-IU-2014-13661).

Paratypes. Papua New Guinea. KAVIENG Stn KB 06, 02.6866°’S, 150.6866°E, 8 m, 4 June 2014: 1 F 2.0 mm (MNHN-IU-2014-13639).― Stn KS 15, 02.6866°S, 150.6866°E, 3–5 m, 6 June 2014: 1 ov. F 2.2 mm (MNHN-IU- 2014-2176).― Stn KS 23, 02.6800°S, 150.7116°E, 4–7 m, 8 June 2014: 1 ov. F 1.8 mm (MNHN-IU-2014-13528), 3 M 1.1–1.5 mm, 1 ov. F 1.9 mm (MNHN-IU-2016-5835).― Stn KD 78, 02.7100°S, 150.7233°E, 6–10 m, 26 June 2014, 1 M 2.7 mm (MNHN-IU-2014-13565) .

Other material. Papua New Guinea. KAVIENG Stn KB 18, 02.6800°S, 150.7116°E, 4–7 m, 8 June 2014: 1 M 2.0 mm (MNHN-IU-2014-13623).― Stn KD 36, 02.5850°S, 150.4833°E, 8 m, 16 June 2014: 1 ov. F 2.2 mm (MNHN-IU-2014-13530).― Stn KS 41, 02.6100°S, 150.5483°E, 2–7 m, 16 June 2014: 2 M 1.7–1.9 mm (MNHN- IU-2014-13647).― Stn KS 43, 02.5866°S, 150.4850°E, 4–12 m, 16 June 2014: 8 M 1.2–1.7 mm, 3 ov. F 1.8–2.0 mm, 5 F 1.4–1.6 mm, 2 postlarvae 1.0 mm (MNHN-IU-2016-5851) .

Etymology. Named after Jeff Kinch, formerly Principal of Papua New Guinea National Fisheries Authority’s, National Fisheries College in Kavieng.

Description. Carapace: Robust or massive, sexually dimorphic (wider on females), 0.9 (males), 0.8 (females) × as long as broad; transverse ridges elevated, upraised dorsally, densely covered with short setae, long and thick setae absent. Gastric region convex (upraised) with some transverse ridges: epigastric ridge distinct, medially interrupted, unarmed; anterior protogastric ridge usually medially and laterally interrupted, with few scales to carapace margin, often followed by few short scales; anterior mesogastric ridge scale-like, laterally interrupted by anterior branch of cervical groove, continuing with few scales, often followed by few short scales; anterior metagastric ridge not medially interrupted, laterally interrupted, followed by scales on posterior metagastric region. Mid-transverse ridge not interrupted, cervical groove distinct, followed by 3 not interrupted or minutely interrupted ridges, interspersed with 1 laterally interrupted or scale-like ridge, and some scattered scales. Lateral margins clearly convex, with 7–8 spines: first anterolateral spine well-developed, exceeding lateral orbital spine, second spine (hepatic) small, slightly dorsomesially from lateral margin, and followed by 5–6 branchial spines behind distinct anterior cervical groove (3 anterior and 1–2 posterior). Rostrum leaf-like, horizontal, dorsally flattish or slightly concave, sexually dimorphic (near bottle-shaped for males) [1.5]1.4–1.7 × as long as broad, length [0.4]–0.5 and breadth 0.2–[0.3] that of carapace; lateral margins smooth and convex, with well-developed basal supraocular and subapical spines. Pterygostomian flap ending in blunt tooth; upper margin unarmed.

Thoracic sternum: Sternite 3 moderately broad, [2.0]–2.5 × as wide as long, anterior margin convex, with anterolateral projections. Sternite 4 widely contiguous to sternite 3; surface flattened, smooth; greatest width 3.0 × that of sternite 3, [2.5]–2.7 × as wide as long.

Pleon: Elevated ridges upraised dorsally, with few short setae.Tergites 2–4 with anterior and posterior transverse elevated ridges; tergites 5–6 smooth.

Eye: Eyestalk length about 0.9 × broader than long, peduncle distally setose, not distinctly expanded proximally; maximum corneal diameter1.0 × rostrum width, about as wide as eyestalk.

Antennule: Article 1 longer than wide, with 3 distal spines: distomesial spine absent, pair of distolateral spines present; proximal lateral spine absent.

Antenna: Article 1 with prominent mesial process distally clearly not reaching lateral antennular spine. Article 2 unarmed, sometimes with minute distomesial spine. Articles 3 and 4 unarmed.

Mxp3: Ischium with distinct distal spines on flexor and extensor margins. Merus [0.5]–0.6 × length of ischium, with 0–1 median small spine and well-developed distal spine on extensor margin and 2 spines on flexor margin.

P1: 2.6–2.7 × carapace length (male) [1.5]–1.6 (female); subcylindrical, moderately spiny and with scattered long stiff setae. Merus 0.5–0.9 length of carapace, [1.7]1.6–1.8 × as long as carpus, with few scattered spines, mesial spines strongest. Carpus [1.5]–1.9 × as long as wide with few scattered spines, mesial most prominent. Palm [1.2]– 1.3 × carpus length, 1.3–3.0 × as long as broad with scattered small spines on dorsal and ventral surfaces, lateral and mesial margins irregular, with scattered small spines. Fingers unarmed, 0.7–[0.9] × palm length.

P2–4: Moderately stout, setose with few spines. Meri successively shorter posteriorly: P3 merus 0.7–0.9 × length of P2 merus, P4 merus 0.8–0.9 × length of P3 merus. P2 merus, 0.6 × carapace length, 3.8 × as long as broad, 1.1 × 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 1.2 × as long as broad, as long as P4 propodus; extensor margins of P2 and P3 with row of few small spines, proximally diminishing, with distal spine; P4 extensor margin irregular but unarmed; flexor margins irregular, with distal spine on P2–3, absent in P4. Carpi irregular on extensor margins on P2–3, unarmed on P4; distal spine prominent on P2–3, absent on P4; row of small spines below extensor margin on lateral surface of P2–3, unarmed on P4. Propodi stout, 3–4 × as long as broad; extensor margins irregular, usually unarmed; flexor margins with 3–5 slender movable spines in addition to distal pair. Dactyli 0.7–0.8 × length of propodi, ending in incurved, strong, sharp spine; flexor margins with 5–6 well-developed dactylar spines, each with 1 spinule.

Eggs: Ov. F carried approximately 8– 20 eggs of 0.3–0.5 mm diameter.

Colour. Body green-brownish with some whitish and dark brown patches. P1–4 whitish-pale brown, with brownish bands

Genetic data. COI and 16S, Table 1.

Distribution. Papua New Guinea, from 2 to 15 m.

Remarks. Phylladiorhynchus jeffkinchi belongs to the group of species characterized by having the epigastric ridge unarmed, the carapace and pleon ridges elevated, upraised, and dactylar spines on the flexor margins of the dactyli. The new species resembles P. phanus , from Papua New Guinea and P. marina , from Vanuatu. However, P. jeffkinchi can be distinguished from these species on the basis of the following characters:

- The anterior epigastric ridge is always distinct and medially interrupted in P. jeffkinchi , whereas it is often indistinct or scale-like in P. phanus and P. marina .

- The anterior protogastric ridge is often medially interrupted in P. jeffkinchi , whereas it is not interrupted in P. phanus and P. marina .

- The carapace is densely covered by short setae in P. jeffkinchi , whereas these setae are shorter and less dense in P. phanus and P. marina .

- The anterior margin of thoracic sternite 3 is convex and anterolaterally projected in P. jeffkinchi , whereas these anterolateral projections are absent in P. phanus and P. marina .

The specimens of P. jeffkinchi range from 1.0 to 2.7 mm postorbital carapace length. The genetic divergences among P. jeffkinchi , P. marina and P. phanus were 7% (16S) and larger than 14% (COI). The three sequences of P. jeffkinchi from Papua New Guinea diverged 0–0.3% for COI and 0% for 16S.

Figures

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 23. Phylladiorhynchus jeffkinchi n. sp., A-D, G-I, holotype ovigerous female 2.4 mm (MNHN-IU-2014-13661); B, F, paratype male 2.7 mm (IU-2014-13565): A, B, carapace and pleon, dorsal view. C, thoracic sternites 3 and 4. D, left cephalic region, showing antennular and antennal peduncles, ventral view. E, right Mxp3, lateral view. F, left P1, dorsal view. G, left P3, lateral view. H, right P4, lateral view. I, dactylus of right P4, lateral view. Scale bar: A, B, F–H = 1.0 mm; C–E, I = 0.6 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).