Dardanus stimpsoni, Parente & Hendrickx, 2009

Parente, Manuel Ayón & Hendrickx, Michel E., 2009, 2323, Zootaxa 2323, pp. 1-71 : 27-40

Dardanus stimpsoni n. sp.

( Figs. 6C, 13C, 14–19, 36 K-O)

Dardanus sinistripes .— Ball & Haig, 1974: (in part, see material examined and additional material).— Hendrickx, 1990: 41 (in part, see additional material); 1994: 27–31 (in part, see material examined and additional material).— Ayón Parente, 1997: 45 (in part, see additional material).— Hendrickx et al., 1997a: 9 (in part, see additional material).— Hendrickx et al., 1997b: 70–72 (in part, see additional material).— Landa-Jaime et al., 1997: 410 (in part, see additional material).

Material examined. Type material. Holotype male (SL 14.50 mm), Gulf of California , Mexico, 28º36’N, 113º06’W, GUAYTEC II R / V “El Puma”, 06 Aug 1987, 72 m, trawl, EMU-223 . Paratypes: 3 males (SL 12.00– 14.60 mm), 1 ovigerous female (SL 13.40 mm), off Punta San Carlos, BCS, Mexico, 27º59’N, 112º42’W, GUAYTEC II R / V “El Puma”, 04 Aug 1987, 92 m, trawl, EMU-224 ; 1 male (SL 11.40 mm), 26º47’N, 110º06’W, Gulf of California , GUAYTEC II R / V “El Puma”, 01 Aug 1987, 85 m, trawl, EMU-5491 ; 6 males (SL 2.86–3.79 mm), 5 females (SL 2.86–4.07 mm), 6 ovigerous females (SL 3.64–5.00 mm), off Barra de Tonala , Chiapas, Mexico, 15º40’N, 94º12’W, CEEMEX P7 R / V “El Puma”, 10 May 1992, 144 m, trawl, EMU-4812 ; 10 males, (SL 3.29–9.53 mm), 4 females (SL 3.17–5.24 mm), 2 ovigerous females (SL 3.53–4.12 mm), 3 juvs., ATLAS II, 17º07’N, 100º37’W, 20 Abr 1982, 30 m, trawl, EM-3235 ; 3 males (SL 5.70–9.20 mm), “Te Vega”, stn. XVIII-22, La Manzanilla, 19º17.8’N, 104º48.5’W, Tenacatita Bay , Mexico, 25 May 1968, 9- 55 m, LACM CR 1968 - 372.2 ; 46 males (SL 2.20–10.00 mm), 15 females (SL 3.10–4.10 mm), 16 ovigerous females (SL 3.10–4.40 mm), Chamela Bay , Jalisco, Mexico, 16 Feb 1938, 46- 55 m, USNM-1076122 ; 2 males (SL 7.11–7.90 mm), Mulegé , BCS, outside Concepción Bay, Mexico, R / V “Te Vega”, stn. 16-48, 47- 55 m, UAZ-1547 .

Additional material. 5 males (NM), and 3 females (NM), off Teacapán , Sinaloa, Mexico, 22º18’N, 106º10’W, SIPCO II R / V “El Puma”, 22 Aug 1981, 66 m, trawl, EMU-200B ; 2 females (SL 3.10–4.50 mm), off Teacapán , Sinaloa, Mexico, 22º14’N, 106º16’W, SIPCO II R / V “El Puma”, 22 Aug 1981, 109 m, trawl, EMU-200C ; 1 male (NM), off Teacapán , Sinaloa, Mexico, 22º24’N, 105º54’W, SIPCO I R / V “El Puma”, 23 Apr 1981, 35 m, trawl, EMU-200D ; 1 female (4.95 mm), off Mazatlán , Sinaloa, Mexico, 23º8’N, 106º25’W, SIPCO I R / V “El Puma”, 25 Apr 1981, 27 m, trawl, EMU-201A ; 1 female (SL 3.00 mm), off Mazatlán , Sinaloa, Mexico, 23º8’N, 106º32’W, SIPCO II R / V “El Puma”, 24 Aug 1981, 78 m, Van Veen dredge, EMU- 201B ; 1 female (SL 5.30 mm), off Piaxtla Point , Sinaloa, Mexico, 23º34’N, 106º57’W, SIPCO I R / V “El Puma”, 24 Apr 1981, 66 m, trawl, EMU-203 ; 1 male (SL 8.40 mm), Mazatlán Bay , Sinaloa, Mexico, 23º13’N, 106º27’W, BBMAZ C4 R / V “ FC1 ”, 26 Sep 1979, 15 m, trawl, EMU-204A ; 1 male (SL 5.90 mm), Mazatlán Bay , Sinaloa, Mexico, 23º13’N, 106º27’W, BBMAZ C14 R / V “ FC1 ”, 25 Aug 1980, 22 m, trawl, EMU-204B ; 1 female (SL 7.10 mm), Mazatlán Bay , Sinaloa, Mexico, 23º13’N, 106º27’W, BBMAZ C17 R / V “ FC1 ”, 20 Jan 1981, 27 m, trawl, EMU-204C ; 1 male (SL 14.90 mm), off Altata Bay , Sinaloa, Mexico, 24º30’N, 108º11’W, CICLO I shrimper “Crestón I”, 56 m, trawl, EMU-205 ; 1 male (SL 14.15 mm), Topolobampo , Sinaloa, Mexico, 25º33’N, 109º7’W, 12 Apr 1984, 0 m, with the hand, EMU-206 ; 1 juv., off Punta Mita , Nayarit, Mexico, 20º52’N, 105º32’W, CORTES 1 R / V “El Puma”, 14 May 1982, 57 m, trawl, EMU-207A ; 9 males (SL 3.07–11.75 mm), 3 females (SL 3.73–4.90 mm), 2 ovigerous females (SL 4.81–4.97 mm), off Punta Mita , Nayarit, Mexico, 20º54’N, 105º28’W, CORTES 1 R / V “El Puma”, 14 May 1982, 37 m, trawl, EMU-207B ; 1 male (SL 14.20 mm), 2 females (SL 8.90 mm), off Arboleda Point , Sonora, Mexico, 26º53’N, 110º6’W, CORTES 3 R / V “El Puma”, 31 Jul 1985, 40 m, trawl, EMU-208 ; 4 males (SL 4.52–16.40 mm), 5 NS, N of Tiburón Island , Sonora, Mexico, 29º11’N, 112º31’W, CORTES 3 R / V “El Puma”, 02 Aug 1985, 77 m, trawl, EMU-209 ; 4 males (NM), off San Miguel Cape , Baja California, Mexico, 28º8’N, 112º41’W, CORTES 3 R / V “El Puma”, 01 Aug 1985, 53 m, trawl, EMU-210A ; 1 male (SL 16.60 mm), off San Miguel Cape , Baja California, Mexico, 28º9’N, 112º42’W, CORTES 3 R / V “El Puma”, 01 Aug 1985, 102 m, trawl, EMU-210B ; 1 male (SL 11.50 mm), off Arboleda Point , Sonora, Mexico, 26º51’N, 110º5’W, CORTES 1 R / V “El Puma”, 05 Aug 1982, 53 m, trawl, EMU-211 ; 1 females (SL 7.15 mm), off Fuerte River , Sinaloa, Mexico, 25º40’N, 109º28’W, CORTES 2 R / V “El Puma”, 14 Mar 1985, 31 m, trawl, EMU-213A ; 4 males (SL 5.00– 14.70 mm), 3 females (SL 5.50–7.70 mm), off Santa María Bay , Sinaloa, Mexico, 25º2’N, 108º31’W, CORTES 1 R / V “El Puma”, 03 May 1982, 28 m, trawl, EMU-216A; 1 ovigerous female (SL 6.15 mm), off Santa María Bay, Sinaloa, Mexico, 24º59’N, 108º41’W, CORTES 3 R / V “El Puma”, 09 Aug 1985, 52 m, trawl, EMU-216C ; 1 male (SL 2.90 mm), 2 females (SL 3.42–3.97 mm), Novillero , Nayarit, Mexico, 22º22’N, 105º56’W, BIOCAPESS VI R / V “El Puma”, 29 Jun 1992, 44 m, trawl, EMU-4830C ; 2 males (SL 7.18–12.60 mm), off Presidio River , Sinaloa, Mexico, 23º4’N, 106º19’W, BIOCAPESS VI R / V “El Puma”, 29 Jun 1992, 24 m, trawl, EMU-4830D ; 9 males (SL 4.60–10.00 mmm), 9 ovigerous females (SL 3.44–7.00 mm), off Copalita River , Oaxaca, Mexico, 15º46’N, 95º59’W, CEEMEX P7 R / V “El Puma”, 14 May 1992, 75 m, trawl, EMU-4831A ; 1 male (SL 11.30 mm), off San Mateo del Mar , Oaxaca, Mexico, 16º1’N, 95º2’W, CEEMEX P7 R / V “El Puma”, 09 May 1992, 46 m, trawl, EMU-4831B; 3 ovigerous females (SL 3.34–3.45 mm), off Encrucijada, Chiapas, Mexico, 14º47’N, 93º0’W, CEEMEX P7 R / V “El Puma”, 12 May 1992, 60 m, trawl, EMU-4831C ; 1 male (SL 10.80 mm), 1 female (SL 12.90 m), Los Puentes Cuates, Mazatlán, Sinaloa, Mexico, 27 Oct 1995, gill net, EMU-4934A ; 1 male (SL 13.50 mm), Bajo Los Cardones , Mazatlán, Sinaloa, Mexico, 23º10’43”N, 106º24’17”W, 14 Feb 1995, EMU-4936 ; 1 male (SL 12.73 mm), Capultita Island , Ensenada Altata-Pabellón, Sinaloa, Mexico, 05 Mar 1991, 2 m, EMU-8464 ; 2 males (SL 2.29–5.43 mm), 3 females (SL 3.57–5.43 mm), Santa María Bay , Sinaloa, Mexico, 09 Jun 2005, 10 m, trawl, EMU-8465 ; 7 males (SL 2.40–14.10 mm), 2 females (SL 2.33–4.33 mm), 3 ovigerous females (SL 4.17–6.33 mm), Santa María Bay , Sinaloa, Mexico, 09 Jun 2005, 24 m, trawl, EMU-8466 ; 53 males (SL 1.70–10.25 mm), 10 females (SL 3.40–7.00 mm), Santa María Bay , Sinaloa, Mexico, 17 Mar 2006, 10 m, trawl, EMU-8467 ; 1 female (SL 8.39 mm), Santa María Bay , Sinaloa, Mexico, 27 Mar 2007, 10 m, trawl, EMU-8468 ; 2 males (SL 10.50–13.10 mm), SE Tiburón Island, GUAYTEC I R / V “El Puma”, 28º39.9’N, 112º12.8’W, 19 Feb 1987, EMU-8469 ; 1 male (SL 3.30 mm), 1 female (SL 5.1 mm), 2 ovigerous females (SL 4.20-5.40 mm), CEEMEX P8 R / V “El Puma”, 28 Jun 1992, 44 m, trawl, EMU-8470 .

(All specimens in holdings of CEC; all samples collected in shrimp trawl) 2 males (SL 7.13-7.33 mm), 1 female (SL 4.13 mm), off Manzanillo , Colima, Mexico, 19º04.89’N, 104º21.23’W, DEM III cruise, 08 Mar 1996, 37 m; 3 males (SL 6.93–12.20 mm) , 2 ovigerous females (SL 6.20–9.13 mm), off Cuyutlán , Colima, Mexico, 18º55.95’N, 104º07.07’W, DEM I-7 cruise, 07 Jun 1995, 37 m; 3 males (SL 5.00– 7.80 mm) , 1 ovigerous female (SL 4.93 mm), off El Coco, Jalisco, Mexico, 19º09.13’N, 104º38.13’W, 27 Jun 1995, 18 m; 2 males (SL 11.30–14.00 mm) , 1 female (SL 5.33 mm) , off Cuitzmala , Jalisco, Mexico, 19º21.74’N, 105º01.25’W, DEM I cruise, BIP V, 13 Jun 1995, 37 m; 1 male (SL 5.40 mm) , off Cuitzmala , Jalisco, Mexico, 19º21.74’N, 105º01.25’W, DEM I cruise, BIP V, 13 Jun 1995, 37 m; 3 males (SL 5.53-13.80 mm) , 1 female (SL 4.20 mm) , 1 ovigerous female (SL 5.60 mm), off Cuyutlán , Colima, Mexico, 18º56.01’N, 104º07.64’W, DEM I cruise, 07 Jun 1995, 55 m; 5 males (SL 5.67–9.70 mm) , off Navidad Bay , Jalisco, Mexico, 19º10.09’N, 104º42.06’W, DEM IV-3 cruise, 20 Jun 1996; 3 males (SL 4.40–10.00 mm) , 1 female (SL 4.67 mm) , off Cuyutlán , Colima, Mexico, 18º56.01’N, 104º07.64’W, DEM II cruise, BIP V, 07 Dec 1995, 55 m; 2 males (SL 5.47–6.73 mm) , off Manzanillo , Colima, Mexico, 19º06.57’N, 104º22.09’W, DEM I cruise, 02 Jun 1995, 18 m; 5 males (SL 4.00– 9.40 mm) , off Navidad Bay , Jalisco, Mexico, 19º10.02’N, 104º41.08’W, DEM III-3 cruise, 19 Mar 1996; 2 males (SL 3.53–4.20 mm) , off Manzanillo , Colima, Mexico, 19º03.06’N, 104º22.09’W, DEM II cruise, 06 Dec 1995, 73 m.

(All specimens in holdings of EM) 22 males (SL 2.65–9.53 mm), 6 females (SL 2.35–4.76 mm), 4 ovigerous females (SL 2.94–4.47 mm), 5 juvs., ATLAS II, 16º37’18” to 16º37’06”N, 99º17’12” to 99º16’W, 08 Feb 1989, 22 m, EM-3242 ; 3 males (SL 6.50–18.00 mm), 2 females (SL 5.83–7.92 mm), 1 ovigerous female (SL 8.50 mm), ATLAS III cruise, 16º36’36” to 16º36’56”N, 99º32’36” to 99º33’30”W, 17 Jan 1983, 57 m, EM-3272 ; 4 males (SL 3.92–9.17 mm), 2 females (SL 5.67–6.58 mm), ATLAS II cruise, 16º38’ to 16º38’18”N, 99º40’24” to 99º41’48”W, 17 Abr 1982, 54 m, EM-3275 ; 2 males (SL 8.50–9.17 mm), 1 ovigerous female (SL 7.50 mm), ATLAS I cruise, 17º34’ to 17º34’36”N, 101º30’ to 101º31’W, 12 Feb 1982, 60 m, EM-3278 ; 4 males (SL 6.08–7.33 mm), 4 females (SL 3.42–9.33 mm), ATLAS I cruise, 17º58’12” to 17º51’48”, and 102º12’48” to 102º11’36”W, 02 Feb 1982, 44 m, EM-3285 ; 6 males (SL 5.25–15.75 mm), ATLAS II cruise, 16º58’12” to 16º54’36”N, 100º05’54” to 100º04’54”W, 02 May 1989, 123 m, EM-3305 ; 2 males (SL 9.25–12.88 mm), ATLAS III cruise,16º34’36” to 16º34’48”N, 99º05’06” to 99º06’18” W, 16 Jan 1983, 53 m, EM-3306 ; 2 males (SL 6.38–9.38 mm), ATLAS II cruise, 7º28’ to 17º28’18”N, 101º18’48” to 100º22’06”W, 22 Apr 1982, 22 m, EM-3315; 4 males (SL 4.86–8.13 mm), 1 female (SL 10.63 mm), ATLAS II cruise, 17º45’ to 17º44’N, 101º42’ to 101º41’W, 22 Apr 1982, 22 m, EM-3335; 3 males (SL 5.50–13.00 mm), ATLAS III cruise, 17º15’30” to 17º16’12”N, 01º05’ to 101º06’06”W, 13 Jan 1983, 72 m, EM-3336 ; 8 males (SL 2.89–6.89 mm), 3 females (SL 3.22–4.89 mm), ATLAS I cruise, EM-4253 ; 10 males (SL 4.67–9.11 mm), 5 females (SL 3.56–7.22 mm), ATLAS I cruise, EM-4259 ; 1 male (SL 15.22 mm), ATLAS II cruise, 16º58’54” to 16º59’48”N, 100º18’54” to 100º20’W, 19 Apr 1985, EM-4285 ; 8 males (SL 7.78–13.89 mm), 3 females (SL 7.00– 9.22 mm), ATLAS III cruise, EM-4287 ; 1 female (SL 4.16 mm), ATLAS II cruise, 21º37’18 to 21º40’N, 106º09’ to 107º07’30”W, 27 Apr 1982, 114 m, EM-3757 ; 1 male (SL 4.22 mm), 4 females (SL 3.44–4.44 mm), ATLAS II cruise, 21º24’ to 21º23’N, 105º40’ to 105º37’54”W, 26 Apr 1982, 56 m, EM-3759 ; 6 males (SL 2.78–6.67 mm), ATLAS II cruise, 21º47’48 to 21º46’30”N, 105º56’ to 105º55’W, 27 Apr 1982, 54 m, EM-3767 ; 5 males (SL 8.33–11.44 mm), 3 females (SL 11.11–12.56 mm), ATLAS IV cruise, 18º08’02” to 18º07’59”N, and 103º09’22” to 103º10’12”W, 09 Jul 1983, EM-3813 ; 5 males (SL 3.22– 6.00 mm), 2 females (SL 2.78–3.22 mm), ATLAS III cruise, 57 m, EM-4062 ; 1 male (SL 11.56 mm), 2 ovigerous females (SL 4.78 mm), ATLAS III cruise, 16 Jan 1983, 100 m, EM-4327 ; 6 males (SL 2.89–5.33 mm), 14 females (SL 2.67–5.33 mm), ATLAS II cruise, 21°29’ to 21°27.4’N, 105°32.42’ to 105°30.42’W, 52 m, EM-4070 ; 1 male (SL 9.78 mm), ATLAS III cruise, 17º48’12” to 17º48’36”N, 101º48’ to 101º49’06”W, 19 Jan 1983, 100 m, EM-4323 ; 4 males (SL 6.44–9.33 mm), ATLAS III cruise, 17º00’24” to 17º00’00”N, 100º26’48” to 100º25’30”W, 17 Jan 1983, EM-4350 ; 1 male (SL 7.78 mm), ATLAS V, 21º01.6’N, 105º33.7’W, 27 Aug 1988, 36 m, EM-10309; 1 ovigerous female (SL 5.44 mm), ATLAS V, 21º01.6’N, 105º33.7’W, 27 Aug 1988, 36 m, EM-10310 .

(All specimens in holdings of LACM CR) 1 male (SL 11.80 mm), off Robelar, Sinaloa, Gulf of California , stn. VS-BII-30, no date available, 88 m, LACM CR 1959 - 001.1 ; 5 males (SL 5.00– 6.70 mm), 1 female (SL 5.2 mm), off San Lorenzo River, Sinaloa, Gulf of California , 10 May 1959, 49– 57 m, LACM CR 1959 - 001.2 ; 12 males (SL 6.60–11.10 mm), 2 ovigerous females (SL 5.90–6.10 mm), off Piaxtla Point, 23º33.3’N, 106º52.6’W, Sinaloa, Gulf of California , stn. VS-BII-33, 13 May 1959, 44– 48 m, LACM CR 1959 - 001.3 ; 2 males (SL 8.90– 9.70 mm), 5 females (SL 8.10–9.10 mm), off Concepción Bay, Gulf of California , stn. 681-37, 15 Mar 1937, 5.5 m, LACM CR 1937 - 083.2 ; 9 males (SL 3.20–5.80 mm), Tenacatita Bay , Mexico, 18 Feb 1938, 46– 73 m, LACM CR 1938 - 001.1 ; 1 male (SL 7.30 mm), off Punta Bahía Kino , Sonora, 27 Mar 1960, 24 m, LACM CR 1960 - 005.1 ; 1 female (SL 4.60 mm), N of Lobos Point, Sonora, Gulf of California , stn. 725-37, 26 Mar 1937, 18 m, LACM CR 1937 - 128.2 ; 1 male (SL 7.40 mm), S of Tiburón Island, Gulf of California , stn. 1044-40, 25 Jan 1940, 4 m, LACM CR 1940 - 016.1 ; 1 female (SL 5.50 mm), S. of Tiburón Island, Gulf of California , stn. 566-36, 11 Mar 1936, 37 m, LACM CR 1936 - 080.1 ; 1 male (SL 3.00 mm), 1 female (4.7 mm), Angeles Bay on spit, Gulf of California , stn. 539-36, 3 Mar 1936, 2 m, LACM CR 1936 - 053.2 ; 2 males (SL 10.00– 13.70 mm), 1 female (SL 8.20 mm), off Acapulco , Mexico, 26 Jan 1860, coll. A. Agassiz, MCZ-1124 .

(All specimens in holdings of USNM) 1 juv., Gulf of California , Mexico, 27º45’N, 110º45’W, R / V “ Albatross ”, 31 Mar 1889, 37 m, beam trawl, USNM- 265369 ; 1 female (SL 4.00 mm), Gulf of California , Mexico, 27º45’N, 110º45’W, R / V " Albatross ", 31 Mar 1889, 37 m, beam trawl, USNM-265363 ; 2 males (SL 14.80–17.50 mm), Concepción Bay , Gulf of California, no date available, USNM-1076123 ; 2 males (SL 7.10–7.84 mm), Tenacatita Bay , Jalisco, Mexico, 19º18’N, 104º51’W, 11 Apr 1937, 13 m, USNM-1075613 ; 2 males (SL 5.70–6.20 mm), 1 female (SL 5.2 mm), 14 juvs., Isabela Island , Nayarit, Mexico, Allan Hancock Expedition, stn. 277-34, 05 Mar 1934, USNM-1076119 .

Diagnosis. Merus of third maxilliped with at least 2 spines on ventral margin. Left cheliped short and broad. Setae on outer face of palm of left cheliped short, plumose, reaching to base of the next scale. Scales on the palm of left cheliped large and evenly subcircular. Outer lower angle of carpus of left cheliped bearing a small spine. Upper face of dactyl of left cheliped with 2 rows of scale-like tubercles, fringed anteriorly with rounded granules. Outer face of palm of the left cheliped and the lateral face of the left third pereopod dactyl and propodus with short to moderately short plumose setae. Lateral face of dactyl of left third pereopod with scales on both sides of longitudinal groove, fringed with small rounded tubercles or spines and short plumose setae. Corneous-tipped spines along entire ventrolateral margin of the dactyl of the left third pereopod.

Description. Shield ( Fig. 14A, B) 0.94–1.10 times larger than broad; anterior margin between rostrum and lateral projections shallowly concave; lateral margins convex, somewhat irregular, with scattered small spines or tubercles on anterior 0.20 and tufts of long setae. Posterior margin rounded. Anterolateral margins usually with a few granules or small spines. Dorsal surface of shield flat, with tufts of long setae; weakly calcified; Y-shape line present posteriorly. Rostral tooth indistinct or weakly produced. Lateral projections large, obtusely triangular or rounded, produced, usually with 1 small submarginal spine. Posterior carapace lateral elements well calcified, unarmed. Branchiostegites unarmed.

Ocular peduncles ( Fig. 14A, B) 0.40–0.60 length of shield, moderately to very thick and weakly compressed in the middle, with 7 long setae on the upper notch. Cornea moderately to strongly dilated, 1.20– 1.45 the width of the base of ocular peduncle; corneal length 0.36–0.55 of ocular peduncle length. Ocular acicles ( Fig. 14A–C) broad, distal margins each with 3–6 spines, separated by 0.33–0.50 width of an acicle. Interocular plate ( Fig. 14C) subrectangular transversally, with pair of protrusions.

Antenular peduncles ( Fig. 14A, D) slender; when fully extended exceeding to ocular peduncles by 1.25– 1.50 length of ultimate segment; ultimate segment with 3 or 4 long stiff setae dorsally; penultimate segment with tufts of long setae on ventral and dorsal surfaces; basal segment ( Fig. 14D) with ventromesial distal angle bearing small spine, ventral margin with 4–6 small spines.

Antennal peduncles ( Fig. 14A, B, E) when fully extended reaching 3/4 or exceeding by 1/4 length of ocular peduncles; fifth segment unarmed, with tufts of short setae on ventral and dorsal surfaces; fourth segment with 1 or 2 very small spines or spinules on laterodistal margin and tufts of long setae on the ventrolateral margin; third segment with 1 small spine at ventral subdistal margin and tufts of long setae; second segment with dorsolateral distal angle produced, ending in strong simple or bifid spine, lateral margin unarmed, dorsomesial distal angle bearing 1 or 2 spines, mesial margin setose; first segment with ventrolateral distal angle with 1 or 2 small spines, ventral surface produced, rounded. Antennal acicle ( Fig. 14A–C, E) reaching 1/2 ocular peduncle length up to 1/4 length of cornea; dorsomesial margin with 4 or 5 small spines, occasionally with 6; dorsolateral margin usually with 1 or 2 small spines, ventrolateral margin unarmed or with 1 or 2 small spines; terminating in bifid spine. Antennal flagella with very short setae on each articulation.

Maxillule ( Fig. 15A) with internal lobe bearing 1 proximal seta and 4–8 stiff setae or bristles distally. Maxilla ( Fig. 15B) with endopod exceeding slightly in distal extension the scaphognathite; scaphognathite moderately broad. First maxilliped ( Fig. 15C) with endopod reaching approximately 3/4 length of external basal segment and occasionally bearing a long apical bristle. Second maxilliped ( Fig. 15D) without distinguishing characters. Third maxilliped ( Fig. 15E) with basis-ischium incompletely fused; basis with 1 or 2 moderately strong spines on ventrolateral distal margin, spines concealed by tufts of long setae; ischium with well developed crista dentata, with 8–11 denticles; ventrolateral distal margin with strong spine; merus with 2–4 spines on ventral margin, dorsal distal margin with small spine.

Chelipeds vastly unequal, left larger. Left cheliped ( Figs. 6C, 16A) very stout, 1.30–1.60 times longer than wide, more elongate in males than in females, armature generally similar in males and females. Dactyl ( Figs. 16C) terminating in large corneous tooth; cutting edge with 5 strong molar teeth; outer face with row of strong spine-like tubercles; upper face with 2 rows of scale-like tubercles, fringed anteriorly with 1–4 small granules and short plumose setae; upper inner face with row of corneous-tipped tubercles and two longitudinal rows of short setae. Fixed finger terminating in large corneous tooth; cutting edge with 6 molar teeth. Palm ( Fig. 16A–B) with outer face strongly convex; outer face of palm and fixed finger covered with scales fringed on their distal edge with 1–13 small rounded granules and short plumose setae; inner surface with numerous rounded spine-like tubercles accompanied with long stiff setae; lower margin ( Fig. 16D) bearing row of strong, triangular-shaped corneous spines; upper margin with double row of 5–9 prominent, corneous-tipped spines. Carpus ( Fig. 16A) with upper margin bearing 4 prominent, corneous-tipped spines; upper face with 3 irregular rows of corneous-tipped spines, the middle row with larger spines; outer face slightly convex with few corneous-tipped spines, lower, outer face with corneous-tipped spines on distal and proximal margins; inner surface with scattered tufts of long setae; ventromesial distal angle with 3 or 4 teeth or rounded spines. Merus ( Fig. 16E) with distal margin of lateral face bearing several corneous-tipped spines, larger on dorsal face; dorsal face with tufts of long stiff setae, subdistal margin with short transverse row of small corneous-tipped spines; ventrolateral distal angle with 1 large spine, occasionally a second, smaller spine present; ventromesial margin crested with 5–8 rounded teeth, proximal larger. Ischium with 5 teeth on the ventromesial margin.

Right cheliped ( Figs. 16F–G) moderately slender, setose. Dactyl terminating in large corneous tooth; cutting edge with 4 or 5 molar teeth; upper margin with 3 rows of moderately large, corneous-tipped spines and tufts of long setae; outer face with tufts of long setae and small corneous-tipped spines. Fixed finger terminating in large corneous tooth; cutting edge with 5 or 6 molar teeth, proximal smaller. Palm with 2 rows of strong, corneous-tipped spines on upper face; outer face with longitudinal rows of flattened tubercles fringed anteriorly with 1 or 2 small spines, at least 3 rows of tubercles extending on fixed finger and many long stiff setae flanked by short setae; lower face with row of strong, triangular corneous spines and tufts of long setae. Carpus with 8 or 9 strong, peripheral, corneous-tipped spines on upper face; outer face convex, with few corneous-tipped spines; lower outer face with scaly tubercles fringed distally with small corneous spines; inner face naked; ventromesial margin with 1 or 2 rounded spines. Merus with tufts of long setae on dorsal margin; dorsodistal margin with 1 strong, corneous-tipped spine; outer face with few flattened tubercles fringed distally with spinules, distal margin with few small corneous spines; laterodistal angle with 1 strong, corneous-tipped spine; ventromesial margin crested with 5 or 6 rounded teeth or spines, proximal larger. Ischium with 4 or 5 spines on ventromesial margin.

Second pereopods ( Fig. 17A–E) and right third pereopod ( Fig. 18A–C) generally similar, but armament of dactyls, propodi and carpi somewhat different between second pair and right third; second pair more slender than right third. Dactyls 1.30–1.40 (second) or 1.40–1.50 (right third) length of propodi, each terminating in strong corneous claw; dorsal surfaces ( Fig. 17B) each with double row of corneous-tipped spines, inner row extending on proximal 0.60, spines accompanied by tufts of stiff setae which on distal third become long, thick spine-like setae; lateral ( Figs. 17A, 18A) and mesial faces ( Figs. 17C, 18B) each with weak longitudinal groove and two rows of tufts of long stiff setae, one in midline and another dorsally, the latter is usually accompanied by small to moderately strong corneous-tipped spines; ventral margins each with 3–7 (second, Figs. 17A, C) or 2 or 3 (right third, Fig. 18A, B) moderately to strong corneous spines distally and tufts of long stiff setae; ventrolateral margin of the left second pereopod with small corneous spines on proximal third. Propodi 1.30–1.40 length of carpi; dorsal faces flattened and very broad (second, Fig. 17E) or comparatively narrower (right third, Fig. 18C), each with 3 (second) or 2 (right third) irregular longitudinal rows of flattened tubercles bearing 1 or 2 small corneous spines accompanied by one long thick setae and 1–3 very short setae, dorsodistal margin with few small corneous spines and thick setae; lateral faces each with two longitudinal rows of tufts of stiff setae, one in midline and another ventrally, in the left second pereopod ( Fig. 17A) ventral row bearing small corneous spines, distal margin with 1 or 2 small corneous-tipped spines; mesial faces ( Fig. 17D) of second pereopods with two longitudinal rows of tufts of stiff setae, one near to midline and another ventrally, the former (in left second) usually bearing small corneous-tipped spines, right third ( Fig. 18B) with one longitudinal row of stiff tuffs in midline and another ventrally, distal margins with 1 small corneoustipped spine; ventral faces each with tufts of long setae, on left second pereopod the tufts also bearing small corneous spines. Carpi 0.60–0.90 (second, Fig. 17A) or 0.80–1.00 (right third, Fig. 18A) length of meri; lateral faces convex with weak longitudinal groove flanked ventrally only with tufts of setae (right third) or tufts of setae accompanied by small corneous spines (second); dorsal margins each with several large, tippedcorneous spines, larger on second pereopods ( Fig. 17E), accompanied by one row of smaller spines. Meri each with tufts of thick setae on dorsal margin; ventrolateral distal margin with 1 strong, corneous-tipped spine; ventral face with irregular simple or double row of small spines or denticles (second) or few small spines or denticles distally (right third) and tufts of long setae. Ischia usually with 1 or 2 small spines ventrodistally.

Left third pereopod ( Figs. 13C, 19A) stout. Dactyl 1.40–1.50 length of propodus, terminating in large corneous claw; dorsal face with longitudinal row of flattened tubercles bearing 1 or 2 small corneous spines and tufts of stiff setae, running close to dorsolateral margin on proximal 3/4; mesial face ( Fig. 19D) convex, with weak longitudinal median groove and two rows of tufts of long, thick stiff setae, one in midline and the other dorsally, the latter bearing 1 or 2 corneous-tipped spines, ventromesial margin with tufts of long setae; lateral face ( Figs. 13C, 19A, B) flattened, with shallow, broad, median longitudinal groove, vanishing distally and bearing small flattened tubercles fringed distally by short plumose setae, transverse scales on both sides of groove; scales with small, rounded or tipped granules and short plumose setae on distal edge, setae longer toward edges of dactyl; scales terminating in strong, rounded or tipped, spine-like tubercles on ventrolateral margin ( Fig. 19A, B), and in strong, corneous-tipped spines on dorsolateral margin ( Fig. 19B, C), spines becoming small corneous spines distally, concealed by long, spine-like, thick setae; ventral face with moderately deep longitudinal groove and 1 or 2 strong corneous spines distally. Propodus ( Figs. 13C, 19A) 1.30–1.40 length of carpus, very broad; dorsal face ( Fig. 18E) with two irregular longitudinal rows of flattened tubercles bearing 1 or 2 small corneous spines, one long thick setae, and 2 or 3 very short setae, distal margin with long thick setae and few small corneous spines; mesial face ( Figs. 18D, 19D) with two longitudinal rows of tufts of short setae, one in midline and another ventrally; lateral face ( Figs. 13C, 19A) convex, with transverse scales on both sides of a bare, middle area; scales fringed distally with small, rounded or tipped spine-like tubercles and short plumose setae, setae longer toward edges of propodus; scales terminating in strong, rounded or tipped spine-like tubercles on ventrolateral margin, and in tubercles bearing 2 corneous-tipped spines on dorsolateral margin. Carpus ( Fig. 19A) 0.80–0.90 length of merus; lateral face convex with short transverse rows of small tipped-corneous spines scarce accompanied by long stiff setae, subdistal margin with few tipped-corneous spines; dorsal margin with row of tipped-corneous spines, larger distally; dorsolateral angle usually with 1 moderately strong, corneous-tipped spine. Merus with tufts of long, thick bristle-like setae on dorsal face; lateral and mesial faces with few tufts of short setae; ventral face with few small rounded spines distally, laterodistal angle usually with 1 small tipped-corneous spine. Ischium usually with 1 ventrodistal spinule.

Sternite XII (third pereopods) ( Fig. 14F) with anterior lobe rectangular, bearing prolonged projection, with tuft of long setae anteriorly.

Fourth pereopod ( Fig. 14G) subchelate; dactyl with 5 or 6 corneous ventral spines on lateral face; propodal rasp well developed; carpus with sharp dorsodistal spine.

Fifth pereopod chelate; rasps of dactyl and propodus well developed.

Male pleon ( Fig. 17F) with second to fifth left pleopods fringed with long setae, each with well developed exopod; small subcircular fleshy membranous protuberance between fourth and fifth pleopods, fringed anteriorly with short setae. Female pleon ( Fig. 17G) with second to fifth left pleopods fringed with long setae; second to fourth triramous; fifth biramous, endopod very small; single, elongate, triangular fleshy membrane fringed with long setae present between fourth and fifth pleopods.

Uropods ( Fig. 17F, G) strongly asymmetrical, left larger than right; endopods and exopods with well developed rasps.

Telson ( Fig. 14H) with lateral constrictions; marginal area partially calcified; posterior lobes separated by median cleft, left larger than right, each with 4 or 5 corneous spines and long setae on terminal margin; anterior lobes with long setae on lateral margins.

Color. In life ( Fig. 26B), carapace light orange with reddish stains on dorsal and lateral faces; shield purple with scattered red spots; ocular peduncles purples with two reddish bands, one distal and one median, ventral face reddish with one median purple band and another purplish-white band distally; cornea golden; antennal segments light purple; antennal and peduncular flagella light orange; chelipeds reddish-purple with many purples tubercles, merus with a red line distally; smaller cheliped with yellow setae with red tip and white stains on distal and proximal margins of carpus and palm, respectively; walking legs light reddishpurple with purples tubercles; carpus and merus each with a median red band, inner face whitish on proximal half.

Etymology. The species is named to honor William Stimpson (1832–1872) in recognition of his enormous contribution to the study of crustaceans, in particular the hermit crabs.

Distribution. Throughout the Gulf of California and along the west coast of Mexico south to off Tonala, Chiapas; 2– 144 m.

Remarks. Based on the numerous specimens of this species found in several collections, it appears that D. stimpsoni is widely spread and the most common species of Dardanus in the eastern Pacific. It also features a very ample bathymetric distribution.

Based on the material examined, ovigerous females of D. stimpsoni range in size from 2.94 to 10.00 mm SL. Minimum size of mature females is very small compared with other species of Dardanus from the eastern Pacific ( Table 1).

Small differences are observed when comparing specimens collected in SW Mexico and specimens from the Gulf of California. Southern specimens present ocular peduncles proportionally longer (0.45–0.60 SL) than those from the Gulf of California (0.40–0.45 SL). The former also feature stouter ocular peduncles and a more dilated cornea (1.33–1.45 width of ocular peduncle basis) than Gulf specimens (1.20–1.25). Compared to ocular peduncle length, corneal length (measured along inner side) is proportionally larger in southern specimens (0.40–0.55) than in Gulf specimens (0.36–0.40). The posterior portion of shield in southern specimens is somewhat narrower than in the Gulf specimens and the latter also feature thinner and longer antennal acicles, usually reaching to ¼ the length of the cornea in lieu of the basis of cornea as in the southern material examined. However, all other characters (e.g., chelipeds, pereiopods 2 and 3, telson) are strikingly similar and these variations are considered intraspecific. Armature on outer face of left cheliped and lateral face of left third pereopod dactyl and propodus, considered diagnostic characters to separate species of eastern Pacific Dardanus , are similar. Although in examined specimens the tuberculation of palm showed some variations in the size of scales and number of granules on distal margin of scales, the type and location of granules is constant. The density and length of setae in scales are also similar (except in juveniles where setae were less dense). The pattern of scales and fringes of setae on lateral faces of dactyl and propodus in the left third pereopod is also similar; setae on these segments are always short and never exceeded length of spines on ventrolateral and dorsolateral margins. Proportion between width of dactyl and propodus of third left pereopod is also similar among all specimens examined.

The sculpture on the palm of the left cheliped, left third pereopod dactyl and propodus distinguishes D. stimpsoni n. sp. from D. sinistripes , D. janethaigae , D. pilosus , and D. magdalenensis . The scales on the palm are larger and more evenly circular in D. stimpsoni , with a major number of granules on the anterior margin; besides, the fringe of setae in scales scarcely reach the basis of the next scale ( Fig. 36K, Table 1). The armature of the inner lower margin of the left cheliped ( Fig. 36L) in D. stimpsoni is different from D. janethaigae , D. pilosus , and D. magdalenensis . The setation on the lateral face of the left third pereopod dactyl and propodus also differentiates D. stimpsoni from the other four species, and the marginal setae of scales are shorter and never exceeding tip of spines on dorsolateral and ventrolateral margins. Moreover, in D. stimpsoni the left third pereopod propodus is slender and is slightly broader than dactyl, whilst in the other species it is moderately broader than dactyl ( Fig. 36N).