Lysiosquilla maculata ( Fabricius, 1793 )

Lysiosquilla maculata ( Fabricius, 1793)

( Fig. 19 View FIGURE 19 )

Squilla maculata Fabricius, 1793: 511 [type locality Manado, Indonesia, by neotype selection (Ahyong 2001)]. Lysiosquilla miersi de Vis, 1883: 321 [type locality Moreton Bay, Queensland, Australia].— Kemp, 1913: 4, 10, 111, 116–117. Lysiosquilla maculata .— Barnard, 1950: 855, fig. 3d.— Stephenson, 1953a: 44, 45.— Stephenson & McNeill, 1955: 246 (Western

Australian specimen only).— McNeill, 1968: 88.— Manning, 1968a: 36–38, fig. 12; 1978d: 3–7, figs. 1–3, 9.— Moosa,

1991: 179.— Manning, 1991: 7.— Ahyong & Lin, 2022: figs. 1D, 2. Lysiosquillina maculata .— Manning, 1995: 134–137, figs. 68c, 70a, b, 71a, b, 72a, b, 74–77, 78a, 80a.—Ahyong, 2001: 137–

139, fig. 67; 2002b: 830.

Material examined. KZN: SAMC-A001333 , 1 ♀ (TL 111 mm), Durban , 29°53’06.6”S 31°00’00.0”E, depth and date unknown, stat. 156 GoogleMaps ; SAMC-A008219 , 1 ♂ (TL 229 mm), Durban , 29°53’06.6”S 31°00’00.0”E, depth and date unknown, coll. H.W. Bell Marley GoogleMaps ; SAMC-A001334 , 1 ♀ (TL 203 mm), Umsunduzi River , Pietermaritzburg, 29°36’59.8”S 30°39’59.8”E, river bank, coll. Dr. Gilchrist. GoogleMaps

Diagnosis. Rostral plate cordiform (occasionally subtriangular), usually broader than long and broadest in advance of base; with distinct median carina anteriorly, not flanked by longitudinal grooves or carinae. Mandibular palp 3-segmented. A2 scale ovate, length about 2.5 times width. Raptorial claw dactylus with 7–11 teeth. TS8 sternal keel rounded. AS 5 smooth dorsally. AS 6 smooth medially; with low lateral boss, medially marked with parallel grooves. Uropodal exopod proximal segment outer margin with 7–9 movable spines; endopod at least 0.66 dark distally; exopod proximal half also dark.

Colour in alcohol: Uropodal endopod with distal 0.75 completely dark; proximal half of uropodal exopod also dark. Dactylus of raptorial claw pale; propodus dark along inner margin. Banding faded in large specimen except for two dark transverse bands on medial section of carapace.

Colour in life (after Ahyong 2001). Dorsum base colour white to pale yellow, with dark brown to black transverse bands. Carapace with three dark, transverse bands intervened by pale bands of about the same width. Uropodal exopod with distal half of proximal segment and proximal 0.66 of distal segment black; endopod with distal 0.66 black. A2 scale with diffuse patch of dark brown chromatophores across central portion.

Measurements. ♂ (n = 2) TL 203–229 mm, ♀ (n = 1) TL 111 mm. CI 375–455. A1 peduncle 0.46–0.52CL. A2 scale length 2.2–4.2 times width and 0.59–0.62CL; entire margin setose. PI 81–86 ( ♂), 81 ( ♀). Uropodal endopod length 1.9–2.0 times width. Roxas & Estampador (1930) recorded the largest known specimen at TL 385 mm.

Distribution and habitat. Indo-West Pacific from South Africa, Mozambique and Madagascar to Australia, Vietnam, Taiwan, Japan and Hawaii. Occupies deep burrows on level intertidal and shallow subtidal habitats in sand and mud flats.

Remarks. Lysiosquilla maculata is the largest and most widely distributed species of the genus in the Indo-West Pacific. However, due to the recent revisions within the family, it is expected that many reported examples of L. maculata could refer to other species of Lysiosquillidae and many earlier records of L. maculata require verification ( Manning 1978d; Ahyong 2001; Ahyong & Lin 2022). Within the Iziko collection, two specimens of L. tredecimdentata Holthuis, 1941 were misidentified as L. maculata . Meanwhile, Barnard (1950) recorded specimens of L. maculata up to TL 300 mm, but these specimens are considered lost and cannot be verified. Sexual dimorphism is recorded particularly for large females and is observed in the relative size and number of spines of the raptorial claw ( Manning 1995; Ahyong 2001). Females larger than 230 mm have the propodus of the raptorial claw shorter than the carapace and exhibit a reduced number of teeth on the dactylus, usually 7–8 (Ahyong 2001). This is compared to the usually longer propodus in smaller specimens with more teeth. While the present series only records 9–10 teeth, Ahyong (2001) diagnosis of the species records 7–11 teeth (usually 10–11) on the dactylus of the raptorial claw.

Until recently, the species was placed in Lysiosquillina and while this genus is now considered a synonym of Lysiosquilla , L. maculata is still characterized by its broad antennal scale; its length being less than 3.0 times its greatest width. Ahyong & Lin (2022) define three major clades of Lysiosquilla : the ‘maculata clade’ is defined for species that share the broadened antennal scale and lack the anteromesial antennal spine and contains L. maculata and other species previously in Lysiosquillina . Species of the second clade have dorsally spinulate and scabrous telsons, AS 6 and uropods, while the third clade containing L. tredecimdentata consists of the remaining dorsally non-spinose species with an elongate or ovate pereopod 1 endopod.

The specimens present in this study mostly agree with published accounts of the species ( Manning 1978d, 1995; Ahyong 2001). Most specimens agree with the diagnosed proportions of the antennal scale length being 2.5 times its width. However, the largest male examined appears to have a slenderer antennal scale with a length 4.2 times its width. This previously unrecorded variation could be due to its long storage in ethanol since the early 1900s as these structures are quite soft with minimal calcification so easy deformed during preservation. Otherwise the specimen exhibits the feature combination of the three-segmented mandibular palp (distinguishing L. maculata from Lysiosquillina lisa Ahyong & Randall, 2001 ), and the blunt and rounded shape of the TS8 sternal keel (distinguishing L. maculata from L. tredecimdentata ), assuring this identification within the genus Lysiosquilla as currently understood ( Ahyong & Lin 2022).