Phylladiorhynchus tiphys, 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 : 136-138

Phylladiorhynchus tiphys n. sp.

( Figs. 50K , 52 )

Type material. Holotype. New Caledonia, SURPRISES Stn DW 1395, 18.2933°S, 163.0316°E, 34–36 m, 13 May 1999: M 2.4 mm (MNHN-IU-2014-13794).

Paratypes. New Caledonia. CHALCAL 2 Stn DW 80, 23.4500°S, 168.0333°E, 80–160 m, 31 October 1986: 2 M 2.4–2.9 mm, 1 ov. F 2.1 mm (MNHN-IU-2016-477) .

Etymology. From the name Tiphys, an Argonaut, son of Hagnias. The name is considered a substantive in apposition.

Description. Carapace: As long as or slightly longer than broad; transverse ridges with dense short setae and few scattered long and thick iridescent setae. Gastric region slightly convex with 4 transverse ridges: epigastric ridge distinct with 2 median spines, scale between spines with thick setae, short scales laterally; anterior protogastric ridge not medially interrupted, nearly extending laterally to carapace margin; anterior mesogastric ridge not medially interrupted, laterally continuing to first branchial spine, interrupted by interception with cervical groove; anterior metagastric ridge scale-like. Mid-transverse ridge not interrupted, medially slightly depressed, preceded by a shallow or indistinct cervical groove, followed by 2 uninterrupted or minutely interrupted ridges, interspersed with 1 short lateral ridge and few short scales. Lateral margins straight or slightly convex, with 6 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 4 branchial spines (3 anterior and 1 posterior). Rostrum leaf-like, horizontal, dorsally convex, [1.2]–1.7 × as long as broad, length 0.4 and breadth 0.3 that of carapace; lateral margins minutely serrated and convex, with well-developed supraocular basal spines and small subapical spines. Pterygostomian flap with anterior spine, upper margin smooth.

Thoracic sternum: As wide as long. Sternite 3 moderately broad, 1.2–[1.5] × as wide as long, anterior margin convex, anterolaterally projected. Sternite 4 widely contiguous to sternite 3; anterolaterally smooth, surface depressed in midline, smooth; greatest width [3.0]–3.5 × that of sternite 3, 2.5–3.0 × as wide as long.

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

Eye: Eyestalk length about [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 [0.6] × rostrum width, as wide as eyestalk.

Antennule: Article 1 slightly 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 not reaching lateralmost antennular spine. Article 2 with well-developed distomesial and distolateral spines. Articles 3 and 4 unarmed.

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

P1: [2.4]–3.0 (males), 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 [0.8]–0.9 length of carapace, [1.3]–2.0 × as long as carpus. Carpus 2.0–[2.5] × as long as wide. Palm [1.1]–1.2 × carpus length, 2.0–[2.2] × as long as broad. Fingers unarmed, [0.7]–0.8 × palm length, spine at hingepoint of palm-finger joint.

P2–4: Stout, setose and spinose. Meri successively shorter posteriorly: P3 merus [0.9] × length of P2 merus, P4 merus [0.7] × length of P3 merus. P2 merus, [0.7] × carapace length, [3.5]–4.7 × as long as broad, 1.2 × as long as P2 propodus; P3 merus [3.9] × as long as broad, [1.1] × as long as P3 propodus; P4 merus [3.2]–3.5 × as long as broad, 0.9 × 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 some spines; flexor margin irregular, with distal spine on P2–4. Carpi with 4 spines on extensor margin on P2–3, unarmed on P4; distal spine prominent on P2–3, absent on P4; granules below extensor margin on lateral surface of P2–4; flexor margin unarmed. Propodi stout, [4.5–5.5]5.5–6.0 × as long as broad; extensor margin irregular, armed with 3 spines; flexor margin with 3–4 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 5–6 movable spines.

Eggs: Ov. F (MNHN-IU-2016-477) carried 17 eggs of 0.3 mm diameter.

Live colour. Unknown.

Genetic data. COI and 16S, Table 1.

Distribution. New Caledonia, between 34 and 160 m.

Remarks. Phylladiorhynchus tiphys belongs to the group of species having 2 epigastric spines, 1 hepatic spine, and 3 spines on the anterior branchial margin. Phylladiorhynchus tiphys closely resembles to P. zetes from the French Polynesia (see the differences under the Remarks of this species). The specimens range in size from 2.1 to 2.9 mm postorbital carapace length.

Figures

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 52. Phylladiorhynchus tiphys n. sp., holotype male 2.4 mm (MNHN-IU-2014-13794): 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, right P2, lateral view. G, right P3, lateral view. H, right P4, lateral view. I, dactylus of right P2, lateral view. Scale bar: A, E–H = 1.0 mm; B–D, I = 0.6 mm.