Sympagurus dimorphus (Studer, 1883)

Landschoff, Jannes & Lemaitre, Rafael, 2017, Differentiation of three common deep-water hermit crabs (Crustacea, Decapoda, Anomura, Parapaguridae) from the South African demersal abundance surveys, including the description of a new species of Paragiopagurus Lemaitre, 1996, ZooKeys 676, pp. 21-45 : 28-31

publication ID

https://dx.doi.org/10.3897/zookeys.676.12987

publication LSID

lsid:zoobank.org:pub:C7512B16-9B82-4F45-8EB7-138474095F73

persistent identifier

https://treatment.plazi.org/id/A7FBBE2C-2DAC-4856-ECE3-14D6F33B88CE

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scientific name

Sympagurus dimorphus (Studer, 1883)
status

 

Sympagurus dimorphus (Studer, 1883) Fig. 7A, B, 8

Primary synonyms: Eupagurus dimorphus Studer, 1883: 24, figs 11, 12 (type locality: South Atlantic Ocean, South Africa, off Cape of Good Hope, S.M.S. “Gazelle”, 34°13.6'S, 15°00.7'E, 211 m).

Parapagurus brevimanus Balss, 1911: 4, fig. 5.

? Eupagurus modicellus Stebbing, 1914: 255, pl. 26, fig. D. (See "General distribution").

Sympagurus var. arcuatus johnstoni Hale, 1941: 279, fig. 13 a–d.

Sympagurus var. arcuatus mawsoni Hale, 1941: 280, fig. 14 a–c.

Material examined.

South Africa, West Coast. WCDSS2012, AFR279: 4 males 9.5-12.0 mm, 1 ovig. female 8.1 mm, sta A32144-4116, S32°18.26', E16°18.53', 369 m, 11 Jan 2012 (SAMC MB-A066808). WCDSS2015, AND004: 1 ovig. female 9.7 mm [inside stomach of Monk fish], sta C0400-3330, S33°55.08', E17°39.26', 285 m, 20 Jan 2015 (SAMC MB-A066807); 4 males 10.0-12.0 mm, 5 ovig. females 7.7-9.1 mm, 1 female 9.4 mm, sta C0367-3336, S33°58.11', E17°52.51', 220 m, 9 Feb 2015 (SAMC MB-A066801); 1 male 7.4 mm, sta C0379-3130, S36°34.74', E20°38.10', 12 Feb 2015 (SAMC MB-A066805); 1 female 7.1 mm, sta C0458-5008, S29°57.54', E14°49.40', 448 m, 8 Mar 2015 (SAMC MB-A066803). WCDSS2016, CCH008: 1 male 7.8 mm, sta D00640, S31°28.02', E16°05.64', 470 m, 21 Feb 2016 (SAMC MB-A066806); 1 male 11.2 mm, sta D00726-2446, S32°22.98', E17°27.78', 199 m, 11 Mar 2016 (SAMC MB-A066492).

South Africa, South Coast. SCDSA 2015, AND005: 1 male 14.6 mm, sta D0520-4071, S36°27.78', E21°53.58', 401 m, 20 Apr 2015 (SAMC MB-A066839); 1 male 12.0 mm (SAMC MB-A066840), 1 male 13.2 mm (SAMC MB-A066841), sta D00521-4043, S36°25.50', E21°27.12', 192 m, 20 Apr 2015; 1 male 4.9 mm, sta D00540-6542, S35°21.30', E22°49.98', 585 m, 26 Apr 2015 (SAMC MB-A066833); 1 male 12.7 mm, sta D00561-6671, S34°05.22', E26°55.68', 466 m, 1 May 2015, (SAMC MB-A066818); 1 male 10.3 mm, sta D00565-4224, S34°10.20', E26°46.38', 425 m, 2 May 2015 (SAMC MB-A066823); 1 male 6.5 mm, 1 female 7.5 mm, sta D00582-4153, S34°54.96', E23°22.08', 210 m, 7 May 2015 (SAMC MB-A066820). SCDSA 2016, CCH009: 1 male 11.3 mm, sta D00757-4020, S36°49.19', E20°33.72', 538 m, 4 May 2016 (SAMC MB-A066802); 2 males 10.1-10.4 mm, 3 ovig. females 6.8-7.6 mm, sta D00812-4174, S34°46.80', E24°12.30', 196 m, 19 May 2015 (SAMC MB-A066804); 1 male 8.8 mm (SAMC MB-A066490), 1 ovig. female 9.4 mm (SAMC MB-A066491), sta D00819, S34°52.32', E23°35.70', 195 m, 21 May 2016.

Diagnosis, taxonomy, larval and juvenile morphology.

See Lemaitre (1989; 1990; 1996; 2000; 2004b), Lemaitre and McLaughlin (1992), and Poore (2004).

Colour (in life; Fig. 7A, B). Until now, information on colour of Sympagurus dimorphus had been based on three published photographs taken of live specimens inside their gastropod housing (Lemaitre 2000, pl. 7; 2004b, fig. 35a; Poore 2004: pl. 17c), and formalin-preserved specimens with patterns still visible ( Lemaitre 2004b). Although the basic colour pattern can be discerned in those photographs, the specimens used have only partially visible body parts, and furthermore, the exposures of the images show somewhat distorted colour tones. Herein, we present for the first time a high quality colour photograph of the entire body removed from it’s housing of a freshly caught male and of an ovigerous female specimen (Fig. 7A, B), which accurately show complete colour tones and patterns. The photographs show that the background colour of the body is white, or white and light amber on the chelae. The shield has orange and reddish patches arranged more-or-less symmetrically on the calcified portions. The ocular peduncles are white, each with an orange-red stripe on the dorsal face, and a light orange ventral face. The antennular peduncles are semi-transparent. The antennal peduncles each have a light orange-red patch on the laterodistal face of the second segment, and an orange stripe on the lateral faces of the fourth and fifth segments; the flagella are semitransparent or light orange. The right cheliped has the chela mostly light amber with white spines or tubercles, and white patches medially; the carpus is orange dorsally, with white spines or tubercles; the merus is red dorsally, with bright white lateral and mesial faces. The colour pattern of left cheliped is similar to that of right cheliped. The ambulatory legs have dactyls mostly white except for a light orange proximally; the propodus and carpus are white except for two light orange stripes (one dorsolateral, and one ventrolateral) on the lateral face of both segments, and the mesial face of both segments are similar to the lateral face; the merus is bright white except for a dorsolateral red stripe broadening distally near the distal margin; the ischium is white with a dorsolateral light orange stripe. The pleon is orange or reddish. The uropods and telson are white with light orange.

General distribution.

Reported from the Southern hemisphere from 22°S to 57°S. Depth: 91-1995 m.

As discussed by Lemaitre (2004b), Eupagurus modicellus Stebbing, 1914 from Ascencion Island, was believed by Manning and Chace (1990) to represent S. dimorphus . However, Stebbing’s taxon was based on a juvenile specimen that likely does not represent S. dimorphus . Thus, the presence of this species as far north as Ascencion Island in the South Atlantic is considered questionable.

South African distribution

(Fig. 8). Highly abundant all along the west coast, common on and along the shelf of the Agulhas Bank on the south coast, extending to offshore areas of East London; depth range of material in this study is 170-585 m.

Common names.

"Monkey-nut hermit crab", "Cloaked hermit crab".

Habitat.

Found living in gastropod shells, usually with actinian or zoanthid polyp attached to the shell, or in carcinoecia formed by colonies of Epizoanthus sp.; young have been found in scaphopod shells ( Lemaitre 2004b). On the south coast of South Africa, commonly found in gastropod shells that are not covered by anthozoan symbionts.

Genetic data.

Sta D0520-4071, S36°27.78', E21°53.58', 401 m, male 13.2 mm, BOLD: SEAKY876-15 (MB-A066841). Sta D0520-4071, S36°27.78', E21°53.58', 401 m, male 14.6 mm, BOLD: SEAKY962-15 (MB-A066839).