Lysiosquilloides Manning, 1977

Ahyong, Shane T. & Lin, Chia-Wei, 2022, Garypus sanasai Lin, Huang & Chang 2022, sp. nov., Zoological Studies 61 (12), pp. 1-14 : 6-10

Lysiosquilloides Manning, 1977

Lysiosquilloides Manning, 1977: 84–85 . Type species Lysiosquilla aulacorhynchus Cadenat, 1957 , by original designation and monotypy. Gender masculine.

Diagnosis: Rostral plate anteriorly with median sulcus. Eye large, T-shaped, cornea strongly bilobed, mesial lobe distinctly conical (less pronounced in Ls. siamensis ). Dorsal processes of antennular somite low, blunt, without anterolateral spine. Antennular peduncle article 1 with prominent lateral crista, disto- and proximolateral corner almost a right-angle; article 2 lateral margin weakly cristate. Antennal protopod margin anterior to mesial papilla with prominent, anteromesial projection, distally uncalcified, papillate, apex soft, pointed. Mandibular palp present. Telson submedian teeth with movable apices; submedian denticles present adults; median boss with posterior spine or blunt lobe.

Composition: Lysiosquilloides aulacorhynchus ( Cadenat, 1957) ; Ls. mapia Erdmann & Boyer, 2003 ; Ls. siamensis ( Naiyanetr, 1980) , Ls. taiwanica sp. nov.

Remarks: Lysiosquilloides is most easily distinguished from Lysiosquilla by the movable (versus fixed) submedian teeth on the telson, presence of submedian denticles in adults, conical mesial lobe of the cornea (most prominent in Ls. mapia and Ls. taiwanica ), the median boss of the telson having a short posterior spine or lobe (unarmed in Lysiosquilla ), the low, unarmed dorsal processes of the antennular somite and the large, papillate dorsomesial projection on the antennal protopod. A new distinguishing feature of Lysiosquilloides identified here is in the ornamentation of the lateral margin of antennular peduncle articles 1–2: a distinct lateral crista on article 1 and weakly cristate margin on article 2. In Lysiosquilla , antennular peduncle article 1 is weakly cristate, and article 2 is subcylindrical and smooth, without a lateral crista.

In parallel with Lysiosquilla as revised herein, Lysiosquilloides includes species with slender through broad antennal scales. The antennal scale is most slender in Ls. aulacorhynchus (length 2.9–3.1 × width), broadest in Ls. mapia and Ls. taiwanica sp. nov. (~2.5) and somewhat intermediate in Ls. siamensis (2.4–2.7) ( Manning 1977; Ahyong 2001; Erdmann and Boyer 2003).

Lysiosquilloides taiwanica sp. nov. ( Figs. 3 , 4 ) urn:lsid:zoobank.org:act:45635710-340F-4D12-81A0-744D19B07241

Type material: NMMBA CD5609, male holotype (TL 145 mm), Hojie, Pingtung County, Taiwan, 26–28 m, from burrow in sandy bottom close to coral reef, coll. C.-W. Lin, 18 February 2017.

Diagnosis: Cornea mesial lobe distinctly conical, apex bluntly pointed. Antennal scale broad, length 2.50 × width. Rostral plate ovate, slightly longer than wide, widest at midlength; apex deflexed; with short median sulcus anteriorly. Raptorial claw dactylus with 7 teeth. Thoracic somite 8 sternal keel blunt, angular. Telson length 0.70 × width; with median boss terminating in small spine. Uropodal protopod with small ventral spine anterior to endopod articulation; endopod extending posteriorly slightly beyond telson posterior margin.

Description: Eye large, cornea set slightly obliquely on stalk, extending to end of antennular peduncle article 2 ( Fig. 3A ); cornea mesial lobe distinctly conical, apex bluntly pointed; CI 347. Ophthalmic somite anterior margin obtusely angular, unarmed; ventral margin with bluntly rounded median keel ( Fig. 3D ). Ocular scales produced as slender spines, directed anterodorsally ( Fig. 3C ).

Antennular peduncle length 0.46CL; articles 1–2 lateral margin with straight, narrow crista, widest on article 1 ( Fig. 3E ). Antennular somite dorsal processes low, broad, subquadrate, apices short, acute directed anteriorly ( Fig. 3A ).

Antennal protopod with 1 mesial and 2 ventral papillae; anteromesial margin with prominent, elongate lobe, basally sclerotised, distally papilliform, larger and longer than mesial papilla, apex inclined anteriorly ( Fig. 3A, F ). Antennal scale length 2.50 × width; 0.51CL; entire margin setose ( Fig. 3A ).

Rostral plate ovate; slightly longer than wide; widest at midlength; margins convex, almost straight in proximal one-third; apex slightly deflexed, rounded; dorsal surface with median sulcus anteriorly; ventral surface smooth ( Fig. 3A, B ). Carapace anterolateral angles rounded; posterior margin concave.

Raptorial claw ( Fig. 3G ) dactylus with 7 graded teeth, outer margin broadly convex along distal half, almost straight along proximal half, with shallow basal notch. Propodus longer than carapace, distal margin unarmed; occlusal margin pectinate, with 4 movable spines proximally; PI 73. Carpus dorsal margin terminating in short stout spine, directed ventrally when claw folded. Merus unarmed. Ischium length one-third merus length.

Mandibular palp 3-segmented. Maxilliped 5 basal segment unarmed; merus with broad flange on inner margin, distally truncate ( Fig. 3H ). Maxilliped 1–5 each with epipod.

Thoracic somite 5 lateral process obsolete. Thoracic somites 6–8 lateral process broadly rounded ( Fig. 3I ). Thoracic somite 8 sternal keel angular, blunt ( Fig. 3J ).

Pereopods 1–3 proximal article unarmed; endopod slender, flattened, liguliform ( Fig. 3K–M ).

Pleopod 1 endopod without posterior ‘endite’ ( Fig. 3Q ).

Abdominal somites 1 – 5 with rounded posterolateral angles. Somite 5 smooth medially and laterally; posterior margin unarmed. Abdominal somite 6 ( Fig. 3N ) smooth medially; with low, smooth lateral boss flanked mesially by shallow groove; with acute, triangular ventrolateral projection anterior to uropodal articulation; sternum posterior margin unarmed.

Telson ( Fig. 3N ) subquadrate, wider than long, length 0.70 × width; surface smooth, with few, broad, shallow pits flanking low median and submedian bosses; median boss posterior spine well developed, slightly overreaching posterior telson margin ( Fig. 3O ); margin carina distinct; lateral margins weakly convex, unarmed; articulated submedian teeth slender, conical; 13–16 submedian denticles either side of midline; intermediate and lateral teeth short, slender; intermediate and lateral denticles rounded, each with minute spiniform apex; ventral surface unarmed.

Uropodal protopod ( Fig. 3N, P ) unarmed dorsally except for spine above proximal exopod articulation; with small ventral spine anterior to endopod articulation. Uropodal exopod proximal segment unarmed dorsally; inner distal margin with broad, round lobe; outer margin with 7 movable, distally flattened spines, distalmost spine reaching midlength of distal segment; distal margin with stout ventral spine. Exopod distal segment ovate, length twice width, longer than proximal segment, with dorsal and ventral median carina. Endopod elongate, length 2.45 × width, extending posteriorly slightly beyond telson posterior margin.

Colour in life: ( Fig. 4 ). Carapace and antennal scale transversely banded with pale cream-yellow and dark maroon; maroon bands diffuse, mottled, on anterior half of carapace, solid medially on posterior half, with posterior band black-brown laterally. Raptorial claw dactylus to ischiomerus banded pale yellow and dark maroon. Pereopods proximally yellow, distally translucent white with maroon proximal spot on distal exopod article. Thorax and abdomen transversely banded with pale yellow and black-brown across somite articulations; bands on abdominal somite 6 and telson becoming irregular, blotchy, posterior dark band on telson W-shaped. Uropodal protopod black-brown proximally, pale yellow distally; exopod pale yellow with broad black-brown band across articulation of distal and proximal articles; endopod pale yellow proximally, black-brown distally.

Measurements: TL 145 mm, CL 25.3 mm, cornea width 7.3 mm, antennular peduncle length 11.7 mm, antennal scale length 12.9 mm, raptorial claw propodus length 36.2 mm.

Etymology: Named taiwanica , after the region of the type locality.

Remarks: Like its Indo-West Pacific congeners, Ls. taiwanica has a cordiform-ovate rostral plate ( Fig. 3A, B ) (versus triangular in the West African Ls. aulacorhynchus ), a relatively broad antennal scale (length about 2.5 × width versus 2.9–3.1 in Ls. aulacorhynchus ) and a posterior spine on the median boss of the telson ( Fig. 3N, O ) (blunt, dorsoventrally flattened lobe in Ls. aulacorhynchus ). As in other species of Lysiosquilloides , the apex of the rostral plate is rounded, but also deflexed, and because of the anterior median sulcus on the dorsal surface, the apex can appear to be notched if observed in oblique dorsal view. The new species most closely resembles Ls. mapia in sharing the prominently conical mesial lobe of the cornea with bluntly pointed apex ( Fig. 3A ) (versus conical with rounded apex in Ls. siamensis and Ls. aulacorhynchus ) and angular thoracic somite 8 sternal keel ( Fig. 3J ) (versus quadrate in Ls. aulacorhynchus and Ls. siamensis ). Lysiosquilloides taiwanica and Ls. mapia differ subtly morphologically: the telson is slightly shorter proportionally in Ls. taiwanica (length 0.70 × width versus 0.74) and when the uropod is extended, the endopod extends slightly beyond (versus not reaching) the posterior margin of the telson ( Fig. 3N ). The most striking difference between Ls. taiwanica and Ls. mapia , however, is the live colouration ( Fig. 4 ; Erdmann and Boyer 2003: figs 2, 3). The raptorial claws and anterior half of the cephalothorax are almost uniformly bright orange in Ls. mapia , compared to mottled maroon with diffuse cream banding in Ls. taiwanica . In-situ, Ls. mapia at its burrow mouth is unlikely to be mistaken for other lysiosquillids because of its bright orange cephalothorax, but Ls. taiwanica at its burrow may be overlooked as L. lisa because of often similar mottled cream and maroon colouration. Additionally, the thorax and abdomen are transversely banded with black-brown and yellow in Ls. taiwanica or with black-brown, yellow and orange in Ls. mapia .

Although Ls. taiwanica is confirmed only from Taiwan based on a specimen, underwater photographs of individuals from Milne Bay, Papua New Guinea (https://www.inaturalist.org/observations/19753630) and the Philippines (Moalboal, 7 m: https://www. inaturalist.org/observations/7792398; Leyte Gulf, 24 m: https://www.poppe-images.com/index.php/product/ lysiosquillina-lisa-6/) suggest the species has a wide range in the western Pacific.

Habitat: Burrowing in sandy bottom close to coral reef; with small pieces of coral rubble scattered around the burrow mouth; 7– 28 m.

Distribution: Presently known with certainty only from Taiwan but probably wide ranging in the western Pacific.

Figures

Fig. 3. Lysiosquilloides taiwanica sp. nov., male holotype, TL 145 mm, Hojie, Taiwan, NMMBA CD5609: A, anterior cephalothorax, dorsal view; B, rostral plate, dorsal view; C, ocular scales, dorsal view; D, ophthalmic somite ventral keel, right lateral view; E, right antennular peduncle, dorsal view; F, right antenna, lateral view; G, right raptorial claw, lateral view; H, right maxilliped 5 merus; I, right thoracic somites 6–8, dorsal view; J, thoracic somite 8 sternal keel, right lateral view; K–M, right pereopods 1–3, posterior view; N, posterior abdomen and right uropod, dorsal view; O, posterior telson, right lateral view; P, right uropod, ventral view; Q, right pleopod 1 endopod, anterior view. Scale: A, D–P = 5 mm; B, C, Q = 2.5 mm.

Fig. 4. Lysiosquilloides taiwanica sp. nov., male holotype, TL 145 mm (left raptorial claw missing), Hojie, Taiwan, NMMBA CD5609, colour in life. A, dorsal habitus; B, in habitat.