Goreopagurus poorei Lemaitre & McLaughlin, 2003

Landschoff, Jannes & Lemaitre, Rafael, 2017, Crossing the Indian Ocean: a range extension for Goreopagurus poorei Lemaitre & McLaughlin, 2003 (Crustacea: Decapoda: Paguridae), Zootaxa 4306 (2), pp. 271-278 : 272-277

Goreopagurus poorei Lemaitre & McLaughlin, 2003

( Figs. 1–4 )

Goreopagurus poorei Lemaitre & McLaughlin, 2003: 222 , figs 1–3.— McLaughlin et al., 2010: 29.

New material. Agulhas Shelf. South Coast Survey spring 2016, AFR289: 1 male 4.5 mm, sta A32823–076, 35°14.94’S, 22°50.82’E, 520 m, 5 Oct 2016 ( USNM 1292090 ). Deep Secrets Cruise, ALG230: 1 male 3.9 mm, sta DSC027 DSCS-INV-422, 34°43.74’S, 25°09.06’E, 622 m, 15 Oct 2016 ( USNM 1292091 ) ; 1 female 3.7 mm (USNM 1292088), 1 female 4.5 mm (USNM 1292089), sta DSC006 DSCS-INV-154, 36°45.54’S, 21°12.72’E, 516 m, 1 Oct 2016; 1 female 2.8 mm (damaged), sta DSC012 DSCS-INV-280, 35°07.20’S, 23°02.76’E, 334 m, 6 Oct 2016 (USNM 1292093); 1 female 5.7 mm (USNM 1292087), 1 female 4.0 mm (SAMC MB-A066772), sta DSC003 DSCS-INV-97, 36°01.92’S, 19°42.24’E, 463 m, 30 Sep 2016; 2 males 4.1–4.7 (SAMC MB-A066784), sta DSC003 DSCS-INV-98, 36°01.92’S, 19°42.24’E, 463 m, 30 Sep 2016; 1 male 3.5 mm, 2 ovig. females 2.6–3.1 mm (USNM 1292092), 2 ovig. females 2.6–2.9 mm (SAMC MB-A066771), sta DSC057 DSCS-INV-568, 24°47.10’S, 24°45.60’E, 388 m, 22 Oct 2016.

Description. See Lemaitre & McLaughlin (2003).

Live colouration ( Fig. 1 ). General background orange. Shield light orange fading to white medially and near rostrum, anterior and anterolateral margins. Carapace lateral lobes adjacent to posterolateral margins white. Posterior carapace with branchiostegites orange with numerous minute white punctae; posteromedian plate orange; posterolateral plates white. Ocular acicles white with small orange portion basally on mesial side. Ocular peduncles mottled orange and white on proximal half, distal half mostly white distally except for two orange patches mesially. Chelipeds mostly orange on dorsal, lateral and mesial surfaces, and much lighter orange tone on chela and even lighter on fingers; ventral surfaces nearly white; carpus with light orange tone dorsomedially; merus dorsal surface, lateral and mesial surfaces light orange to white medially, and darker orange distally and proximally. Ambulatory legs each with dactyl white dorsally and light orange ventrally; propodus with weakly defined orange stripe on lateral and mesial faces, otherwise white dorsally and ventrally; carpus mostly orange with undefined white areas dorsally; merus with weakly defined orange stripe on lateral and mesial faces, orange all around distally end mesially, otherwise white dorsally and ventrally; ischium orange.

Distribution. From off eastern Tasmania, Australia, in the western Tasman Sea, and the Agulhas Shelf, off South Africa (see Fig. 4 for South African distribution). Depth range: 334–1,300 m.

Genetic data. Sta DSC006 DSCS-INV-154, 36°45.54’S, 21°12.72’E, 516 m, female 3.7 mm, BOLD: SEAKY1190–17 (USNM 1292088), female 4.5 mm, BOLD: SEAKY1189–17 (USNM 1292089). Sta A32823– 0 76, 35°14.94’S, 22°50.82’E, 520 m, male 4.5 mm, BOLD: SEAKY1187–17 (USNM 1292090). Sta DSC027 DSCS-INV-422, 34°43.74’S, 25°09.06’E, 622 m, male 3.9 mm, BOLD: SEAKY1188–17 (USNM 1202091). Sta DSC012 DSCS-INV-280, 35°07.20’S, 23°02.76’E, 334 m, female 2.8 mm, BOLD: SEAKY1191–17 (USNM 1292093).

Remarks. Goreopagurus poorei had not been reported since its original description by Lemaitre & McLaughlin (2003), which was based exclusively on specimens collected off the Freycinet Peninsula and seamounts of the Southeast Cape, eastern Tasmania. Thus, the presence of this species in South African waters represents a huge range extension to the west and across the Indian Ocean, of approximately 10,100 km (5,400 nautical miles). The specimens in the original description were collected at a depth range of 500–1,300 m, whereas the new specimens herein reported from South Africa were collected at a shallower depth range of 334– 622 m. The broad distribution of this species across such an immense expanse of oceans, covering from the western Indian Ocean to the Tasman Sea in the western Pacific, might appear to be unusual. However, a good number of deepwater paguroids, such as various species in genera of the families Paguridae and Parapaguridae that live at similar depth ranges along the continental slopes, are known to also have the same or even wider distributions in the Indo- West Pacific region (e.g., McLaughlin 1997, 2002, 2004; Lemaitre 1999, 2004a, 2004b, 2013, 2014). Moreover, parallel distribution patterns from southern Australia to southeastern Africa were recently recorded for the caridean shrimp Leontocaris bulga Taylor & Poore, 1998 , and the squat lobster Munidopsis pyrochela Ahyong, 2013 . Whether or not G. poorei will be found between Tasmania and South Africa, across the vast Indian Ocean, can only be determined by more sampling of the varied deep-water habitats that exist in this oceanic region.

Morphological variations of species of Goreopagurus have been sufficiently documented in each of the original descriptions of the four species currently known of this genus ( McLaughlin 1988; McLaughlin & Haig 1995; Lemaitre & McLaughlin 2003; Nucci & Melo 2007). Variations are particularly visible on the expansion of the carpus and length of the chela of right cheliped, which in some species can be attributable to sexual dimorphism ( G. piercei , G. garthi ) or allometric growth ( G. poorei ). In the specimens herein reported from South Africa of G. poorei , we have noticed variations in the ambulatory legs (pereopods 2 and 3) related to sex that do not occur in other congeners or at least have not been discussed in the descriptions of species of Goreopagurus . In G. poorei , males tend to develop distinctly more slender ambulatory legs and longer dactyls than females ( Figs 1 , 2 ), and some females can have distinctly stout segments on the ambulatory legs ( Fig. 2 ). The dactyls in males can be up to nine times as long as wide, whereas in females the dactyls can be short and wide, only about six times as long as wide.

The only appreciable morphological difference between the South African specimens of G. poorei and those from Tasmania used in the original description by Lemaitre & McLaughlin (2003), is in the armature of the dactyls of the ambulatory legs. The dactyls were described by Lemaitre & McLaughlin (2003) as having ventral margins armed with a range of 10–13 corneous spines, whereas the South African specimens reported herein have a range of 12–23 corneous spines. In addition, the preungual process on the dactyl of pereopod 4 is in some specimens obsolete.

The finding in South African waters of numerous specimens of Goreopagurus poorei during South African research surveys, suggests that this species is not rare. Individuals can grow to a relatively large size, and it is probably quite abundant. Thus, it seems this species has simply remained overlooked despite the various taxonomic studies and voluminous reports and catalogs on South African decapods spanning 100 years ( Stebbing 1910; Barnard 1950; Kensley 1969; Emmerson 2016a-c). This discovery also clearly suggests that, like other invertebrates, the paguroid fauna from South Africa is understudied and requires attention.

Figures

FIGURE 1. Goreopagurus poorei Lemaitre & McLaughlin, 2003, Agulhas Shelf, fresh specimens after capture, dorsal view. A, male 4.5 mm, South Coast Survey spring 2016, sta A 32823 – 076 (USNM 1292090); B, female 5.7 mm, Deep Secrets Cruise, ALG 230, sta DSC 003 DSCS-INV- 98 (USNM 1292087); C, same male as A, shield and cephalic appendages, and posterior carapace; D, ovigerous female 3.1 mm, Deep Secrets Cruise, ALG 230, sta DSC 057 DSCS-INV- 568 (USNM 1292092).

FIGURE 2. Goreopagurus poorei Lemaitre & McLaughlin, 2003, left ambulatory legs (pereopods 2 and 3), lateral view: A, B, male 4.5 mm, South Coast Survey spring 2016, sta A 32823 – 076 (USNM 1292090); C, D, female 2.8 mm, Deep Secrets Cruise, ALG 230, sta DSC 012 DSCS-INV- 280 (USNM 1292093). A, C, pereopod 2; B, D, pereopod 3. Scale = 2 mm (A, B), and 1 mm (C, D).

FIGURE 3. Goreopagurus poorei Lemaitre & McLaughlin, 2003, dactyls of left ambulatory legs (pereopods 2 and 3), mesial view: A, B, male 4.5 mm, South Coast Survey spring 2016, sta A 32823 – 076 (USNM 1292090); C, D, female 2.8 mm, Deep Secrets Cruise, ALG 230, sta DSC 012 DSCS-INV- 280 (USNM 1292093). A, C, pereopod 2; B, D, pereopod 3. Scale = 1 mm.

FIGURE 4. Distribution of Goreopagurus poorei Lemaitre & McLaughlin, 2003 along the edge of the Agulhas Shelf, South Africa.