Phylladiorhynchus asclepius, 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 : 17-18

Phylladiorhynchus asclepius n. sp.

( Figs. 5 , 11E , 30G–I, Q, R )

Phylladiorhynchus integrirostris .— Macpherson, 2008: 293–294. (Dampier Archipelago, Western Australia).

Records requiring verification:

Phylladiorhynchus spinosus .— Schnabel & Ahyong, 2019: 335 (in part, only material from Western Australia).

Type material. Holotype. Western Australia. Ningaloo Reef. 22.6083°S, 113.6249ºE, 10 m, 01 May 2009: M 2.1 mm ( UF22296 ).

Paratypes. Western Australia. Ningaloo Reef , 22.6083°S, 113.6249°E, 10 m, 1 May 2009: 1 ov. F 2.1 mm ( UF22401 ) .— 22.681°S, 113.6304°E, 15 m, rubble, 20 May 2006: 1 M 2.4 mm ( UF27886 ) .— Norwegian Channel , 22.6006°S, 113.6274°E, 23 m (in rubble), 28 May 2006: 1 ov. F 2.1 mm ( UF27601 ) .

Other material. Western Australia. Dampier. Stn DA 3/99/50, 20.5473°S, 116.4455°E, 10–20 m, 31 August 1999: 1 M 2.4 mm, 2 ov. F 2.2–2.4 mm ( WAM C27667) .— Vulcan Shoal, Stn 146/K13, 12.7993°S, 124.2667°E, 19 m, 6 October 2013: 1 M 2.4 mm ( WAM C55694-2 ) .

Etymology. From the name Asclepius, an Argonaut, son of Apollo and Coronis or Arsinoe. The name is considered a substantive in apposition.

Description. Carapace: Usually broader than long (0.8–[0.9] × as long as wide); transverse ridges with dense short setae and thick iridescent 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. Midtransverse 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 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 4–5 branchial spines (3 anterior and 1–2 posterior). Rostrum dagger-like, horizontal dorsally flattish or slighly concave [1.8]–2.0 × as long as broad, length 0.5 and breadth 0.2–[0.3] that of carapace; lateral margins serrated 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 quadrangular, [1.4]–2.1 × 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 2.6–[3.1] × that of sternite 3, [2.6]–3.3 × 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 [0.8]–1.0 × rostrum width, [0.8] as long 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 with small to distinct mesial spine. Article 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: [2.3]–2.7 (males), 2.0–2.1 (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]–1.0 length of carapace, [2.0]–2.3 × as long as carpus. Carpus 1.2–[1.3] × as long as wide. Palm [1.3]1.3 × carpus length, [1.4]–1.5 × as long as broad. Fingers [0.9]–1.0× palm length; fixed finger with 0–1 basal spines; movable finger often with 1 basal spine.

P2–4 (P3 lost in holotype): 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, 0.6–[0.7] × carapace length, 3.3–3.8 × as long as broad, 1.1–1.2 × as long as P2 propodus; P3 merus 3.6–3.7 × as long as broad, 1.1–1.2 × as long as P3 propodus; P4 merus 3.7–4.0 × 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, [4.0–4.5]3.8–4.5 × 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 × length of propodi, ending in incurved, strong, sharp spine; flexor margin with dactylar spines at basis of 5–6 movable spines.

Eggs: Ov. F carried approximately 8– 15 eggs of 0.4–0.5 mm diameter.

Live colour. Unknown.

Genetic data. COI and 16S, Table 1.

Distribution. Western Australia, from 8 to 45 m.

Remarks. Phylladiorhynchus asclepius belongs to the group of species having 2 epigastric spines, 1 hepatic spine, 3 spines on anterior branchial margin, rostrum dagger-like (margin straights or nearly straight) and dactylar spines along the flexor margin of the P2–4 dactyli. This species complex includes the following species: P. asclepius , P. euryalus , from Australia (Queensland), New Caledonia and the Chesterfield Islands, P. lini , and P. spinosus Schnabel & Ahyong, 2019 from Australia, New Caledonia and New Zealand. The Western Australian material tentatively referred to P. spinosus by Schnabel & Ahyong (2019) is referable to the new species (Ahyong, pers. com.). These species are morphologically very similar but genetically very distinct (see the differences under the Remarks of P. spinosus ). The examined specimens of P. asclepius range from 2.1 to 2.4 mm postorbital carapace length.

The two sequences of P. asclepius from Western Australia diverged 0.6% for COI and 0.2% for 16S.

Figures

FIGURE 5. Phylladiorhynchus asclepius n. sp., holotype male 2.1 mm (UF22296): 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 P4, lateral view. H, dactylus of right P2, lateral view. Scale bar: A, E-G = 1.0 mm; B–D, H = 0.6 mm.

FIGURE 11. Rostrum, dorsal view. A, Phylladiorhynchus acastus n. sp., paratype male 2.6 mm (MNHN-IU-2017-2646). B, P. amphion n. sp., holotype male 2.4 mm (WAM C55691). C, P. amphion n. sp., paratype female 2.6 mm (WAM C53887). D, P. argus n. sp., paratype ovigerous female 3.5 mm (MNHN-IU-2014-23836). E, P. asclepius n. sp., paratype ovigerous female 2.1 mm (UF22401). F, P. australis Schnabel & Ahyong, 2019, female 4.0 mm (MNHN-IU-2019-2596). G, P. bahamut n. sp., holotype male 2.5 mm (UF40205). H, P. barbeae n. sp., paratype male 2.2 mm (MNHN-IU-2019-2643). I, P. boucheti n. sp., paratype ovigerous female 2.5 mm (MNHN-IU-2017-3830). J, P. butes n. sp., paratype female 2.1 mm (MNHN-IU-2016-449). K, P. cepheus n. sp., paratype male 2.4 mm (MNHN-IU-2014-13858). L, P. eneus n. sp., paratype male 2.1 mm (MNHN-IU- 2014-13801). Scale bars = 1 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.