Sadayoshia benzoniae, Anker & Rodríguez-Flores & Bähr & Barreca & Dunn & Rodrigue & Qurban & Duarte & Pieribone, 2025

Sadayoshia benzoniae sp. nov. Rodríguez-Flores & Anker

( Figs. 1 View FIGURE 1 , 2 View FIGURE 2 )

Material examined. Holotype: female (CL 5.0 mm, PCL 3.6 mm), FLMNH UF 68644 , Saudi Arabia, Red Sea , about 100 km off Al Haridhah, Red Sea Decade Expedition Leg 2, ROV dive CHR0233, 17.387135, 40.827209 to 17.387619, 40.828850, depth: 104–248.5 m, Chimaera Dive Team, processed by F. Benzoni and F. Barreca, 28.03.2022 (CHR0233 / OCX-072) [GenBank Acc. No: PV627001] GoogleMaps . Paratype: male (CL 3.7 mm, PCL 2.5 mm), FLMNH UF 68645 , Saudi Arabia, Red Sea , about 5 km east of Shibara Island, Red Sea Decade Expedition Leg 4, ROV dive CHR0308, 25.407367, 36.775886, depth: 210.1 m, Chimaera Dive Team, processed by S. Bähr and N. Dunn, 16.06.2022 (fcn CHR0308 / OCX-147) GoogleMaps .

Description. Carapace. Sparsely setose, as long as broad; cervical groove distinct; dorsal surface nearly horizontal from anterior to posterior. Each side of carapace with 3 pairs of epigastric spines and 1 parahepatic spine; 3 uninterrupted ridges present on gastric region posterior to epigastric spines; mid-transverse ridge of carapace uninterrupted, preceded by cervical groove. Posterior branchial region laterally with 4 ridges (exclusive of mid-transverse ridge and posterior-most transverse ridges directly anterior to posterior margin of carapace). Dorsal surface with short uniramous and scattered long iridescent setae arising from transverse ridges. Lateral margins slightly convex, subparallel, with 6 spines: 1 st spine anterolateral, directed straight forward, followed by 1 spine on hepatic margin, 3 spines on anterior branchial margin, and 1–2 spines on posterior branchial margin. Rostrum moderately broad, as long as wide, about 0.4 times as long as carapace; dorsal surface nearly horizontal in lateral view, concave from side to side, with dorsal longitudinal carina, without setiferous striae; rostral spine 2.4 times longer than wide (measured at sinus between rostral and anterior lateral spines). Pterygostomian flap rugose, with sparse setae, bluntly produced anteriorly.

Thoracic sternum. Sternal plastron as long as broad; lateral limits divergent posteriorly. Sternite 3 about 3.4 times as broad as long, anterior margin moderately convex. Sternite 4 about 3.9 times longer and twice as broad as preceding sternite, 1.9 times broader than long; surface with 1 anterior stria flanking midline. Following sternites smooth. Lateral parts of sternite 7 smooth.

Pleon. Smooth. Somite 2 unarmed; somites 2–4 without transverse ridges other than anterior one, latter bearing both short and scattered long, uniramous, iridescent setae. Telson with 10 plates.

Eye. Peduncle as long as broad. Cornea slightly dilated; maximum corneal diameter about 0.4 times distance between bases of anterolateral spines; eyelashes short, not reaching mid-length of cornea.

Antennule. Article 1 with distal margin armed with 3 strong and 1 very small distal spines, distolateral spine longer than distodorsal one, distomesial spine much smaller than distolateral and distodorsal ones, distomesial spine minute or obsolescent; lateral margin unarmed; ventral surface unarmed.

Antenna. Article 1 with distomesial small spine not reaching distal margin of article 2. Article 2 with subequal, well-developed, distolateral and distomesial spines, reaching mid-length of article 3. Article 3 with distomesial spine reaching mid-length of article 3, distolateral angle unarmed. Article 4 unarmed.

Mxp3. Ischium with small distal spine on flexor margin; extensor margin unarmed; crista dentata with about 27 small denticles, proximal-most minute. Merus subequal in length to ischium, flexor margin with 2 subequal small spines: distal spine terminal, proximal spine at mid-length; extensor margin unarmed. Carpus unarmed.

P1. Twice as long as carapace, stout, with uniramous iridescent setae along lateral and mesial margins of merus, palm and fingers; dorsal and ventral surfaces of palm and fingers with scattered short setae. Merus about 0.7 times as long as carapace, 2.5 times as long as carpus, with dorsal and lateral spines, and 1 strong distomesial spine. Carpus 0.6 times as long as palm, 0.5 times as long as broad, with 2 rows of small spines on dorsal surface, 1 prominent spine on mesial margin and 3 prominent spines along lateral margin. Palm 0.9 times as long as broad; mesial and lateral margins with strong spines continuing onto fingers, dorsal surface with small spines. Fingers distally spooned; movable finger as long as palm, its mesial margin with 3 spines.

P2–4. Somewhat compressed mesiolaterally, sparsely covered with uniramous iridescent setae and some plumose setae. Meri successively shorter posteriorly; P2 merus 0.8 times as long as carapace, 3.5 times as long as broad, 1.1 times longer than P2 propodus; P3 merus 3.8 times as long as broad, 1.2 times length of P3 propodus; P4 merus 3.8 times as long as broad, 0.9 times length of P4 propodus; dorsal margins of meri with row of proximally diminishing spines in P2 and P3, unarmed in P4; dorsolateral surface unarmed in P2 and P3, with 1 spine on P4; ventrolateral margins with prominent terminal spine. Carpi with 3 spines on extensor margin in P2 and P3, unarmed in P4, distal-most spine largest; lateral surface with 1 spine or unarmed; flexor margins with distal spine. Propodi subequal in length on P2–4, each 4.6–5.2 times as long as broad; extensor margin with 1–2 proximal spines, lateral side unarmed; flexor margin with 6–7 slender movable spines in P2–4. Dactyli subequal in length, 0.7–0.8 times length of propodi, ending in incurved strong sharp spine; flexor margin with 5–6 obsolescent teeth, each with stout spiniform movable spine.

Colour in life. Ground colour of carapace and pleon yellow orange. Carapace with several transverse bands of lavender fringed with deep purple on gastric and cardiac regions, some bands complete, others interrupted near midline; epigastric and post-rostral regions with similar, lavender or lilac-purple patches and spots. Rostrum speckled with small red dots; rostral spines with reddish tips. Pleonites 2–4 with some symmetrically arranged, whitish and orange spots on anterior ridge; pleonites 2–3 whitish with pale orange tinge, pleonites 4–6 bright yellow orange. Eyes brownish yellow. P1 whitish with large pale orange areas and bright red markings on spines; chelae whitish proximally, mostly orange distally, with reddish spots on spines; fingertips whitish. P2–4 with alternating whitish and pale orange transverse bands or rings, orange areas with white spots ( Fig. 2 View FIGURE 2 ).

Etymology. The new species is named after our dear friend and colleague, Francesca Benzoni (King Abdullah University of Science and Technology), for making all the benthic crustacean samples from OceanX expeditions available for study and supporting one of the authors’ (AA) taxonomic work on various groups of Decapoda .

Distribution and bathymetry. Red Sea, at depths of 104–248.5 m.

Ecology. Both specimens were found as “by-catch” in sample baskets with coral rubble and living octocorals.

Remarks. Sadayoshia benzoniae sp. nov. belongs to a small species group within Sadayoshia , which is characterised by (1) the pleonites devoid of spines, smooth, with an anterior ridge only; (2) the shape of the sternite 3, which is more than three times as broad as long; and (3) the antennular article 1 with an unarmed lateral margin. This species group includes only two other species, namely S. actaea Macpherson & Baba, 2012 from New Caledonia (Lifou), and S. latisternata Macpherson & Baba, 2010 from French Polynesia (Austral Islands), New Caledonia (Lifou) and Mauritius ( Macpherson & Baba 2010, 2012). The new species can be distinguished from both species by (1) the rostrum with a dorsal carina, which is absent in S. actaea and S. latisternata ; (2) the proportionally longer rostral spine, about 2.4 times longer than wide vs. 2.1 times longer than wide in S. actaea and S. latisternata ; (3) the antennular article 1 with distomesial spine minute or obsolescent vs. well developed in S. actaea and S. latisternata ; (4) the gastric region of the carapace with 3 uninterrupted ridges posterior to the epigastric spines vs. 4 ridges in S. actaea and S. latisternata ; and (5) the dorsal surface of the carapace with 3 pairs of epigastric spines vs. 4 pairs in S. actaea and S. latisternata , although this last character may be somewhat variable and more specimens need to be examined to confirm its validity (cf. Fig. 1 View FIGURE 1 ; Macpherson & Baba 2010, 2012). The presence or absence of a distomesial spine on the antennal article 3 (present in the new species, absent in S. actaea and S. latisternata ) represent another distinguishing character of the new species (cf. Fig. 1D View FIGURE 1 ; Macpherson & Baba 2010, 2012). In addition, the colour pattern of S. benzoniae sp. nov. differs from that of S. latisternata (cf. Fig. 2 View FIGURE 2 ; Macpherson & Baba 2010); the life colour of S. actaea remains unknown.

Molecular results were fully congruent with morphological evidence. The new species was recovered as sister species of S. actaea , although with low support, in ML analyses ( Fig. 3 View FIGURE 3 ). This clade further clustered with S. latisternata . The COI genetic divergence between the new species and its closest relatives exceeds 8%.