Galathea labidolepta Stimpson, 1858

Botha, Thomas P. A., Griffiths, Charles L., Atkinson, Lara J. & Macpherson, Enrique, 2025, The Galatheidae (Anomura: Galatheoidea) of South Africa, with a description of a new species, Zootaxa 5661 (3), pp. 330-350 : 333-337

Galathea labidolepta Stimpson, 1858

( Figs. 2 , 3 , 7A, B )

Galathea labidolepta Stimpson, 1858: 89 ; Macpherson & Robainas-Barcia, 2015: 153 , fig. 53 (and references cited therein); Emmerson, 2016a: 25; Emmerson, 2016b: 443 (list); Macpherson et al., 2023: 382 (synonymies).

Galathea intermedia . — Barnard, 1946: 378; Barnard, 1950: 283, figs. 91, a–e; Tirmizi & Javed, 1993: 69, fig. 30 (not Galathea intermedia Liljeborg, 1851 ).

Type material. Neotype: South Africa, south of Still Bay , 34°33’45.36”S, 21°18’8.99”E, 62 m, 14/04/2021, SAMC- A094746, ♀ 5.9 mm.

Other material examined. South Africa, 33°44’57.12”S, 26°41’52.08”E, 53 m, 23/09/2016, SAMC-A066507 , 1 ovig. ♀ 4.9 mm ; South Africa, 33°44’57.12”S, 26°41’52.08”E, 53 m, 23/09/2016, SAMC-A066508 , 1 ovig. ♀ 6.0 mm ; South Africa, 33°44’57.12”S, 26°41’52.08”E, 53 m, 23/09/2016, SAMC-A066509 , 2 ♂ 2.5–5.7 mm, 2 ovig. ♀ 3.8–5.0 mm ; South Africa, 33°44’57.12”S, 26°41’52.08”E, 53 m, 23/09/2016, SAMC-A094739 , 2 ♂ 2.5–5.7 mm, 2 ♀ 3.8–5.0 mm ; South Africa, 34°37’38.99”S, 21°53’56.76”E, 78 m, 15/04/2021, SAMC-A094747 , 1 ♂ 3.3 mm, 1 ♀ 4.5 mm ; South Africa, 33°51’22.68”S, 26°38’24.72”E, 97 m, 01/05/2021, SAMC-A094750 , 1 ♂ 4.7 mm, 1 ovig. ♀ 5.6 mm ; South Africa, 34°36’02.16”S, 21°07’0.48”E, 75 m, 14/05/2021, SAMC-A094751 , 1 ♂ 3.0 mm ; South Africa, 29°51’54.79”S, 31°09’11.30”E, 88 m, 05/02/2021, SAMC-A094761 , 4 ♂ 1.4–1.8 mm, 3 ♀ 1.7–2.0 mm, 1 ovig. ♀ 2.4 mm ; South Africa, 29°55’52.54”S, 31°03’45.86”E, 66 m, 26/10/2020, SAMC-A094769 , 4 ♂ 3.2–3.7 mm, 2 ovig. ♀ 2.6–3.7 mm ; South Africa, 29°50’03.98”S, 31°14’08.99”E, 135 m, 05/02/2021, SAMC-A094785 , 2 ♂ 1.8–1.9 mm, 1 ♀ 2.5 mm ; South Africa, 29°49’14.41”S, 31°14’17.05”E, 99 m, 05/02/2021, SAMC-A094789 , 7 ♂ 1.5–2.6 mm, 12 ♀ 1.4–2.4 mm ; South Africa, 29°52’42.31”S, 31°10’00.41”E, 110 m, 05/02/2021, SAMC-A094798 , 31 ♂ 1.4–3.5 mm, 15 ♀ 1.6–2.5 mm, 3 ovig. ♀ 2.3–2.8 mm ; South Africa, 34°03’18.18”S, 25°46’42.72”E, 75 m, 05/04/2022, SAMC-A094800 , 5 ♂ 3.8–6.1 mm, 1 ovig. ♀ 4.3 mm ; South Africa, 34°19’43.68”S, 22°11’44.23”E, 75.2 m, 20/05/2022, SAMC-A094811 , 1 ovig. ♀ 4.5 mm ; South Africa, 34°04’60.00”S, 25°58’60.00”E, 84 m, 25/11/1960, SAMC-A094576 , 1 ♂ 4.6 mm, 8 ♀ 1.7–3.6 mm, 3 ovig. ♀ 3.5–4.3 mm ; South Africa, 34°04’60.00”S, 25°58’60.00”E, 84 m, 25/11/1960, SAMC-A094548 , 1 ♂ 3.2 mm, 1 ovig. ♀ 3.4 mm ; South Africa, 34°02”S, 23°27”E, 42 m, 11/02/1962, SAMC-A094574 , 1 ♀ 2.8 mm ; South Africa, 34°35’S, 21°56’E, 78 m, 28/08/1960, SAMC-A094573 , 1 ♂ 4.5 mm ; South Africa, 30°47.6”S, 30°29.6”E, 44 m, 17/05/1958, SAMC-A094577 , 5 ♂ 2.0– 3.7 mm, 1 ♀ 4.6 mm, 5 ovig. ♀ 2.5–3.2 mm ; South Africa, 34°09’29.88”S, 18°27’0.36”E, 19 m, 28/04/1947, SAMC-A19512 , 3 ♂ 3.9–5.2 mm, 1 ♀ 3.4 mm, 1 ovig. ♀ 5.5 mm ; South Africa, 34°09’23.34”S, 22°47’44.94”E, 69 m, 28/06/2022, SAMC-A094812 , 11 ♂ 2.8–5.9 mm, 6 ♀ 2.3–4.5 mm, 6 ovig. ♀ 4.4–5.0 mm ; South Africa, 33°58’13.08”S, 26° 06’46.92”E, 84 m, 05/04/2022, SAMC-A094765 , 1 ♂ 4.8 mm, 1 ♀ 4.4 mm, 1 ovig. ♀ 3.5 mm .

Description. Carapace: About as long as broad (rarely up to 1.2 times longer than broad); transverse ridges with short dense simple setae; distinct cervical groove, laterally bifurcated. Gastric area with 8 transverse ridges: 2 epigastric ridges, anterior ridge interrupted medially with 1–2 pairs of median spines, posterior ridge scale-like, not extending laterally; 2 protogastric ridges, anterior ridge slightly convex, uninterrupted, without parahepatic spines, posterior ridge scale-like; 1 uninterrupted mesogastric ridge, not extending laterally to anteriormost branchial marginal spines; 3 metagastric ridges, anterior ridge extending laterally to anterior branchial margin, uninterrupted, median ridge laterally interrupted, posterior ridge short, not extending past cervical groove. Hepatic region unarmed or with small hepatic spine occasionally present near anterolateral spine. Cervical groove shallow, followed by uninterrupted mid-transverse ridge and 6 other ridges, 4 ridges uninterrupted. Lateral margins convex, with 7 spines: first well-developed anterolateral spine, slightly posterior to lateral level of orbit; 3 spines on anterior branchial margin and 3 on posterior branchial margin, last spine small. Small spine on lateral limit of orbit, with 1 small frontal spine, infraorbital margin with 2 spines. Rostrum 1–1.6 times as long as broad, 0.4–0.5 times carapace length and breadth 0.3–0.4 that of carapace greatest width; some setose scales on dorsal margin, lateral margin with 4 sharp, deeply-incised teeth.

Pterygostomian flap rugose with 7–8 spines on upper margin near linea anomurica, decreasing in size posteriorly, some ridges with short setae, anterior margin blunt.

Thoracic sternum: As long as broad, lateral extremities somewhat divergent posteriorly. Sternite 3 roughly 3 times wider than long; anterior margin serrated with median notch; sternite 4 2.3 times wider than sternite 3. A few scales on sternite 4.

Pleon: Pleonites 2–4 with 2 uninterrupted transverse ridges each; pleonite 5 with 2 medially interrupted ridges, anterior ridge short; pleonite 6 with 2 short, medially interrupted ridges. Males with G1 and G2.

Eye: Maximum corneal diameter 0.3–0.7 rostrum width; ocular peduncle length 0.8 times width.

Antennule: Article 1 with 2 well-developed distal spines, distodorsal larger, both with tuft of setae, distomesial spine minute. Ultimate article with some short, fine setae on distodorsal margin, not in tuft.

Antenna: Article 1 with well-developed ventral distomesial spine exceeding distal margin of article 2. Article 2 with 2 distal spines, distolateral slightly longer than distomesial, reaching mid-length of article 3. Articles 3 and 4 unarmed.

Mxp3: Ischium with 2 (rarely 1) small spines on distoflexor margin, 1 distal spine on extensor margin; crista dentata with 17–22 (rarely up to 24) denticles. Merus 1.3–2.0 times longer than ischium, flexor margin with 2 subequal spines on distal half, extensor margin with small spine and several eminences and long setae. Carpus, propodus, dactylus unarmed; propodus elongate.

P1: Length 2.9 times carapace length; with scattered, finely setiferous scales, some long, non-iridescent simple setae. Merus 0.8 times carapace length, 1.7 times as long as carpus, spines roughly arranged in rows, dorsomesial and mesial spines stronger, distal spines well-developed. Carpus 0.8 times length of palm, 2.7 times longer than broad; dorsal and lateral surfaces with rows of spines; mesial margin 3–5 spines (distal second strongest). Palm 3.4 times longer than broad, spines arranged roughly in lateral, dorsolateral, mesial and dorsomesial rows; dorsolateral continuing along fixed finger. Fingers 1.2 times length of palm, movable fingers with small spines proximally and well-developed distal spine, fixed finger with row of spines.

P2–4: Moderately slender, with setose striae and long, scattered, non-iridescent simple setae. P2 1.8 times carapace length. Merus shorter successively (P3 merus 0.9 length of P2 merus, P4 merus 0.8 length of P3 merus); P2 merus 0.6 times carapace length, 4.0 times as long as broad, 1.3 times longer than P2 propodus; extensor margin with row of 10–12 proximally diminishing spines on P2–3, only distal spine on P4; flexor margin distally ending in strong spine (with small spine at base occasionally present) followed proximally by 0–1 spines and several eminences, lateral margins unarmed. Carpus with 6–7 spines on extensor margin of P2–3, P4 unarmed; lateral margin with 2 or 3 acute granules sub-parallel to extensor margin; flexor margin with some eminences on P2–3, distal margin acute. Propodus 4.5–4.6 times as long as broad; extensor margin with 1–2 proximal spines on P2–3, P4

unarmed; flexor margin with 6 slender movable spines on P2, P3–4 only 4 spines. Dactylus ending in well-curved strong spines, 0.5–0.6 times length of propodi; flexor margin with 5 or 6 proximally diminishing teeth, distal tooth prominent.

Epipods on P1.

Variation. Ranges noted in description. P1 fingers occasionally gaping distally in males.

Coloration in life. ( Figs. 2 , 7A, B ). Carapace light-orange to brick-red with blue or white spots ( Figs. 2 , 7A, B ); pleomere tergites 2–4 light-orange, often mottled ( Fig. 7B ), posterior tergites and tailfan white. Rostrum and ocular peduncles white to light-orange. Eyes green or light-green. Chelipeds and walking legs orange with some orange/white mottling on meri.

Global distribution. Endemic to South Africa.

South African distribution. False Bay to Durban Bay, 19–135 m ( Fig. 6 ). Neotype from Still Bay, 62 m.

Genetic data. 16S, COI; see Table 1.

Remarks. Galathea labidolepta was the first squat lobster described from South Africa by William Stimpson based on specimens collected from the Cape of Good Hope in 1858. The description was short, though a subsequent publication by Stebbing (1907) included some more information, especially on colour patterns. Unfortunately, the type material was lost during the Chicago fire of 1871, which destroyed the Chicago Academy of Sciences, where the Stimpson collection was held. Later some illustrations were provided by Doflein & Balss (1913), and Lenz & Strunk (1914) using specimens collected along the South African coast. However, due to the short description and few illustrations existing at the time, the taxonomic validity of this species was questioned by different authors and was synonymized with G. intermedia , a common species in the northeast Atlantic (e.g., Barnard 1946, 1950; Tirmizi & Javed 1993). The two species are characterized by the presence of a row of spines along the upper margin of the pterygostomian flap adjacent to the linea anomurica, and the Mxp3 merus is more than twice as long as the ischium. These characters are not observed in other species known from the Pacific and Indian Oceans, but they are common in North Atlantic species (e.g., Zariquiey-Alvarez 1968). Macpherson & Robainas-Barcia (2015) made mention of the similarities between these two species (and others) and highlighted the need for a revision, not only of G. labidolepta , but also G. intermedia (which is in progress).After close examination of the morphology of South African material, it can be confirmed that G. labidolepta is a valid species, distinctly different from G. intermedia and other closely related species; G. bolivari Zariquiey Alvarez, 1950 and G. cenarroi Zariquiey Alvarez, 1968 . The main differences between G. labidolepta and G. intermedia concern ridges on the carapace and pleon, with the former having more ridges and the ridges bearing plumose setae, whereas in the latter there are few ridges with simple setae. The distinction between the species was confirmed by genetic analyses which showed G. labidolepta to have an 11.3–12.0% (COI) divergence from G. bolivari and 11.4–13.0% (COI) from G. intermedia .

The taxonomic confusion between G. labidolepta and G. intermedia is due to their morphological similarities and hence updated descriptions are necessary to avoid future confusion. Therefore, and considering that a name-bearing type is necessary to define the nominal taxon objectively (see International Code of the Zoological Nomenclature), a neotype collected near the original type locality has been chosen. Unfortunately, a neotype could not be collected from the original type locality, though one is selected from nearby. The neotype does, however, closely match with the original description, including the colour pattern provided by Stimpson (1907). This species was frequently collected with other squat lobsters, such as G. hydrae , Trapezionida antonbruuni ( Tirmizi & Javed, 1980) , T. janetae (Tirmizi & Javed, 1992) , T. limula ( Macpherson & Baba, 1993) , and the newly described species detailed below, Galathea noboya sp. nov.

The records of G. labidolepta herein expand the known distribution and depth range of this species (previously False Bay to East London; 18–102 m) to False Bay to Durban Bay (18–135 m). Specimens from across the distributional range had an intraspecific variation (COI) of 0.5–1.2% confirming, along with morphological analyses, that all the material represents G. labidolepta .

Galathea labidolepta is easily distinguishable from others in the genus by the row of spines on the upper margin of the pterygostomian flap (a rare, but unique character). Moreover, the third maxilliped merus is usually twice as long as the ischium ( Fig. 3D ).

Figures

FIGURE 2. Galathea labidolepta Stimpson, 1858 from the Knysna Estuary on an unknown poriferan and exhibiting the blue spots on the dorsal carapace, not collected. Photograph: Dr. Louw Claassens.

FIGURE 3. Galathea labidolepta Stimpson, 1858, neotype, ♀, 5.9 mm (SAMC-A094746), south of Still Bay, South Africa: A, carapace and anterior pleonites, dorsal view; B, sternal plastron, ventral view; C, cephalic region, showing antennular and antennal peduncles, ventral view; D, right Mxp3, lateral view; E, right P2, lateral view; F, right P3, lateral view; G, right P4, lateral view; H, left P1, dorsal view. Scale bar: A, H = 2.0 mm; B–G = 1.0 mm.

FIGURE 6. Marine ecoregions in South African waters (Sink et al. 2019) with distribution of species in the genus Galathea superimposed.

FIGURE 7. Dorsal view of live specimens. A, Galathea labidolepta Stimpson, 1858, Kenton-on-sea, South Africa, ovig. ♀, 6.0 mm (SAMC-A066508); B, Galathea labidolepta Stimpson, 1858, Still Bay, South Africa, neotype, ♀, 5.9 mm (SAMC- A094746); C, Galathea noboya sp. nov., Still Bay, South Africa, ♂ 7.1 mm (SAMC-A094753); D, Galathea noboya sp. nov., Still Bay, South Africa, ♀ 7.5 mm (SAMC-A094752).