Robertgurneya Apostolov & Marinov 1988

Gómez, Samuel, 2020, A new species of Robertgurneya Apostolov & Marinov, 1988, with an illustrated record of R. rostrata (Gurney, 1927), an amended genus diagnosis and comments on R. soyeri (Apostolov, 1974) and R. spinulosa (Sars, 1911) (Harpacticoida Miraciidae), Zootaxa 4861 (4), pp. 451-485 : 452-475

publication ID

https://doi.org/10.11646/zootaxa.4861.4.1

publication LSID

lsid:zoobank.org:pub:9A77EDDD-4A1A-42E7-87E8-E63D455027A9

DOI

https://doi.org/10.5281/zenodo.4428321

persistent identifier

https://treatment.plazi.org/id/03DA87A3-FFF1-FF88-C6DD-8E744C7AC307

treatment provided by

Plazi

scientific name

Robertgurneya Apostolov & Marinov 1988
status

 

Genus Robertgurneya Apostolov & Marinov 1988

Type species. Stenhelia similis Scott A. 1896 (= Robertgurneya similis similis (Scott A. 1896)), by subsequent designation.

Other species and subspecies. Amphiascoides ? arabicus Noodt 1964 (= R. arabica ( Noodt 1964)) , Robertgurneya brevipes Wells & Rao 1987 (= R. brevipes ( Wells & Rao 1987)) , Amphiascus dactylifer Wilson 1932 (= R. dactylifer ( Wilson 1932)) , Amphiascus dictydiophorus Monard 1924 (= R. dictydiophora ( Monard 1924)) , Robertgurneya diversa Lang 1965 (= R. diversa ( Lang 1965)) , Amphiascus ecaudatus Monard 1936 (= R. ecaudata ( Monard 1936)) , Amphiascus falklandiensis Lang 1936 (= R. falklandiensis ( Lang 1936)) , Robertgurneya hopkinsi Lang 1965 (= R. hopkinsi ( Lang 1965)) , Amphiascus ilievecensis Monard 1935 (= R. ilievecensis ( Monard 1935)) , Robertgurneya mexicana sp. nov., Robertgurneya oligochaeta Noodt 1955 (= R. oligochaeta ( Noodt 1955)) , Robertgurneya remanei Klie 1950 (= R. remanei ( Klie 1950)) , Amphiascus rostratus Gurney 1927 (= R. rostrata ( Gurney 1927)) , Robertgurneya similis bulbamphiascoides Noodt 1955 (= R. similis bulbamphiascoides ( Noodt 1955)) , Stenhelia simulans Norman & Scott T. 1905 (= R. simulans (Norman & Scott T. 1905)) , Robertgurneya smithi Hamond 1973 (= R. smithi ( Hamond 1973)) , Robertgurneya soyeri Apostolov 1974 (= R. soyeri ( Apostolov 1974)) .

Amended diagnosis. Miraciidae : Diosaccinae . Body semi-cylindrical compressed. Rostrum elongate, triangular; tip bifurcated, pointed or rounded. Antennule eight-segmented in females; second segment longest, as long as wide or up to three times as long as wide; haplocer and ten-segmented in males. Antenna with allobasis; exopod three-segmented; middle segment smallest; first segment with, second segment with or without seta, third segment with one lateral and two or three apical elements. Mandible with well-developed gnathobasis, biramous; exopod two-segmented, endopod one-segmented. Maxillule biramous; rami one-segmented. Maxilla with three syncoxal endites; endopod two-segmented ( Hamond (1973) described the maxillary endopod of R. smithi “as in other species of the genus” ( Hamond 1973: 66), but it is shown as one-segmented ( Hamond (1973: 12, figure 11(16)); the maxillary endopod of Robertgurneya is diagnosed here as two-segmented until re-inspection of Hamond’s material). Maxilliped subchelate; endopod one-segmented. Female P1–P4 with three-segmented rami; P1 ENP1 longer than exopod; P2–P3 ENP as long as or longer than exopod, P4 ENP shorter than exopod.

Armature formula of P1–P4:

Male P1 basis without “nebendornen” nor nose-like “Chitinzapfen”; with inner dimorphic spine either elongate and about 0.9 times as long as ENP1, or about half the length of ENP1 and with recurved tip, or as long as neighbouring spinule of the basis. Male P2 ENP sexually dimorphic, two-segmented; first segment with one, second segment with one or two proximal setae, and four distal elements. Female P5 EXP with five or six setae, endopodal lobe with four to six elements. Male P5 EXP with five or six, endopodal lobe always with two setae. Caudal rami wider than long, rarely as long as wide, never longer that wide; with seven setae.

Robertgurneya mexicana sp. nov.

(Figs. 1–9)

urn:lsid:zoobank.org:pub:9A77EDDD-4A1A-42E7-87E8-E63D455027A9

Type locality. Urías coastal system, Mazatlán, Sinaloa State, Mexico: stn 2 (23.1587°N, 106.3326°W; depth 1.8 m; organic carbon content 3.99%; organic matter content 6.86%; sand 80.42%; clay 8.29%; silt 11.28%). See also Gómez (in press, Fig. 1) GoogleMaps .

Other localities. Urías coastal system, Mazatlan, Sinaloa State, Mexico: stn 5 (23.2056°N, 106.3715°W; depth 0.6 m; organic carbon content 0.99%; organic matter content 1.71%; sand 78.61%; clay 6.72%; silt 14.67%), GoogleMaps stn 10 (23.1815°N, 106.4214°W; depth 6.0 m; organic carbon content 1.2%; organic matter content 2.07%; sand 69.12%; clay 7.91%; silt 22.97%). See also Gómez (in press, Fig. 1) GoogleMaps .

Type material. Female holotype (ICML-EMUCOP-180119-94) from type locality preserved in alcohol, and male allotype (ICML-EMUCOP-180119-95) from stn 10 dissected and mounted onto six slides, three female paratypes (ICML-EMUCOP-180119-104) from type locality preserved in alcohol, and two female paratypes from type locality dissected and mounted onto nine slides (ICML-EMUCOP-180119-96, ICML-EMUCOP-180119-97); January 18, 2019; S. Gómez leg.

Etymology. The specific epithet refers to the region where the new species was found. It is in the nominative singular, gender feminine.

Description. Female. Total body length measured from tip of rostrum to posterior margin of caudal rami ranging from 390 µm to 450 µm (mean, 423 µm; n, 3; total body length of holotype, 450 µm); habitus fusiform, widest at posterior end of cephalothorax in dorsal view, tapering posteriad.

Prosome (Fig. 1A) consisting of cephalothorax with fused first pedigerous somite, and second to fourth free pedigerous somites; prosomites without expansions nor spinular ornamentation; posterior hyaline frill of cephalothorax, second and third pedigerous somites broad, with posterior margins smooth, of fourth pedigerous somite visibly narrower, finely serrated, without striations.

Urosome (Figs. 1A, C, 2A) consisting of fifth pedigerous somite (first urosomite), genital double-somite, two free urosomites, anal somite and caudal rami; urosomites without expansions, covered with minute denticles dorsolaterally, without surface denticles ventrally. First urosomite (P5-bearing somite) narrower than preceding somites in dorsal view, with pores and posterior sensilla as depicted, posterior frill as in preceding somite dorsally and laterally (Fig. 1A). Genital double-somite rectangular, nearly as long as wide; anterior and posterior halves (second —genital— urosomite and third urosomite, respectively) distinct dorsally (Fig. 1A) and laterally (Fig. 1C), completely fused ventrally (Fig. 2A), with pores as shown; anterior half with dorsal sensilla, and with two short lateral row of posterior spinules on each side (Fig. 1A, C), ventrally with P6 proximally, genital field with epicopulatory bulb medially, and with two short spinular rows close to outer margin on each side (Fig. 2A); posterior half with sensilla as shown dorsally (Fig. 1A), laterally (Fig. 1C), and ventrally (Fig. 2A), with lateral spinules as in preceding half, with posterior hyaline frill finely serrated and striated (Fig. 1C). Fourth urosomite largely as in posterior half of genital double-somite dorsolaterally except for one lateral spinular row only (Fig. 1A, C), seemingly with only one pore ventrally. Fifth urosomite (figs. 1A, C, 2A) without sensilla nor spinules; with dorsal, lateral and ventral pores as shown; posterior hyaline frill finely serrated and striated, dorsal medial part slightly crescentic (Fig. 1C). Anal somite wider than long from dorsal view (Fig. 1C), without anal operculum, cleft medially, with two posterior dorsal sensilla (Fig. 1C); with pores as shown; with small spinules close to joint with caudal rami dorsally (Fig. 1C), with comparatively stronger spinules laterally (Fig. 1A), and with coarse small spinules ventrally (Fig. 2A). Caudal rami 0.4 times as long as wide from dorsal view (Fig. 1C, D); dorsally with transverse posterior row of small spinules (Fig. 1C, D), laterally without spinular ornamentation (Fig. 1A, B), ventrally with two small spinules between large tube pore and seta VI, and with two subdistal inner spinules on each side (Fig. 2A, B); with seven setae as follows: setae I and II situated subdistally on outer margin, the former very small and ventral to the latter; seta III displaced ventrally close to outer margin; setae IV and V normal, with fracture plane, the former shorter; seta VI arising at inner distal corner, as long as seta III; dorsal seta VII issuing subdistally, close to inner margin, triarticulated. Rostrum (Fig. 2A, B) not fused to cephalothorax; elongated, triangular, with blunt tip; with one sensilla arising medially on each side; reaching distal margin of second antennulary segment.

Antennule (Fig. 3A, B) eight-segmented; all segments smooth, except for one proximal and one subdistal dorsolateral row of spinules on first segment; all setae smooth except for pinnate seta on first segment, and two and four biarticulated setae on seventh and eight segments, respectively. Armature formula: 1(1); 2(10); 3(7); 4(3+(1+ae)), 5(2); 6(4); 7(4); 8(5+acro). Acrothek consisting of two setae and one aesthetasc fused basally.

Antenna (Fig. 3C) with small unornamented coxa. Allobasis with remains of former division between basis and first endopodal segment, slightly longer than free endopodal segment, with outer slender spinules proximally; abexopodal seta issuing midway inner margin. Exopod three-segmented; first segment longer than second and third segments combined, second segment smallest; first and second segments unornamented, with one pinnate seta each; third segment with subapical row of spinules, with one bipinnate lateral seta, seemingly with two distal elements only one of which small. Free endopodal segment with proximal and subdistal inner strong spinules, and with two outer frills; armed with two lateral inner spines and two slender setae —the latter set close to each other—, one inner apical spine, three single geniculate setae, one slender short seta, and one strongly spinulose geniculate outer seta fused basally to slender pinnate element.

Mandible (Fig. 4A) with well-developed gnathobasis bearing strong multi- and bicuspidate teeth as shown, with four ventral elements of which ventralmost pinnate and visibly longer. Basis massive, with spinules as depicted, with three inner setae. Exopod two-segmented; first segment larger than second, the former with one lateral and one distal seta, the latter with three apical elements. Endopod one-segmented, visibly larger that exopod; laterally with two setae, distally with one inner free element, and two medial and three outer setae fused basally.

Maxillule (Fig. 4B) with arthrite ornamented with some slender spinules; armed with two surface setae, seven distal spines as shown, one spinulose element, and one recurved stiff pinnate ventral seta. Coxal endite with few inner spinules, with three distal setae of which one thicker. Basis armed with two lateral, one subdistal and three distal elements, one of which visibly thicker. Rami one segmented, exopod with two pinnate setae, endopod with four smooth elements.

Maxilla (Fig. 4C) with large syncoxa ornamented with long outer spinules; with three endites; proximal endite smallest, with two setae; middle and distal endites nearly subequal in length, the former with two, the latter with three setae. Basis drawn out into strong pinnate claw, additionally with strong pinnate spine, and two slender setae —one anterior, one posterior. Endopod two-segmented; first segment with two, second segment with four setae.

Maxilliped (Fig. 4D) subchelate. Praecoxa small, trapezoidal, unornamented. Coxa elongate, with medial and subdistal spinules as shown; with two inner setae issuing subdistally one of which visibly shorter, and one distal seta. Basis longer than coxa, elongate, with one posterior and one anterior row of spinules as depicted, with one medial inner and one subdistal inner seta. Endopod one-segmented, elongate, with three setae —one lateral, one subdistal and one distal small seta— and apical claw.

P1 (Fig. 5A) with broad, short unornamented intercoxal sclerite. Praecoxa triangular, with transverse row of minute spinules. Coxa massive, with spinular ornamentation as shown. Basis with inner and outer spinulose spines; with slender long inner spinules proximally, and with shorter and stronger spinules close to insertion of inner and outer spines, and distally on medial distal rounded extension. Exopod three-segmented, arising at a lower level than the endopod and reaching distal third of ENP1; ENP1:EXP length ratio 1.2; first and third exopodal segments subequal in length, second segment shorter, with spinular ornamentation as shown; first and second segments without inner armature, third segment with four elements. Endopod three-segmented, arising from pedestal; ENP1 elongate, about 5.4 times as long as wide, and 2.3 times as long as second and third segments combined, with outer strong and inner slender long spinules, with one inner stiff, long, and strongly pectinate seta arising subdistally; second and third segments with strong outer spinules as shown, the former nearly as long as wide and half as long as the latter, with one inner long seta; third segment elongate, about 2.7 times as long as wide, with one inner distal slender seta, one apical long element, and one outer distal spine.

P2 (Fig. 5B) with narrow, tall intercoxal sclerite with acute distal projection on each side. Praecoxa triangular, with transverse row of minute spinules. Coxa with three anterior and one posterior row of spinules as shown. Basis with distal inner acute projection; with long inner spinules proximally, with small spinules close to insertion site of endopod, and with longer spinules distally on medial extension and at base of outer element. Rami three-segmented; endopod and exopod subequal in absolute length. Exopod arising at a lower level than the endopod, reaching distal third of ENP3; exopodal segments with outer spinules as shown; EXP1 and EXP2 with outer distal acute projection —of EXP1 shorter—, both segments with coarse inner distal hyaline frill; EXP1 without, EXP2 with inner seta; EXP3 with six elements —three outer spines, two apical elements, and one inner seta. Endopod arising from pedestal at a higher level than exopod; endopodal segments with strong outer spinules; ENP1 and ENP2 subequal in length, ENP3 longest; ENP1 with inner distal acute projection, with outer subdistal pore, with distal inner hyaline frill, with one short inner element; ENP2 ornamented as ENP1, but with additional distal outer acute projection, with inner long seta; ENP3 with outer spinular ornamentation as in previous segment, with medial pore, with one inner and two apical setae, and one outer spine.

P3 (Fig. 6A) with intercoxal sclerite, praecoxa and coxa as in P2. Basis largely as in P2 except for shorter inner spinules proximally and for smaller inner distal acute projection. Rami three-segmented, exopod slightly longer than endopod. Exopod largely as in P2. Endopod largely as in P2 except for two inner setae on P3 ENP3.

P4 (Fig. 6B) with intercoxal sclerite, praecoxa, coxa, and basis as in P3. Exopod longer than endopod, largely as in P3 except for two inner setae on P4 EXP3. Endopod reaching middle of EXP3; largely as in P3 except for one inner seta only on P4 ENP3.

Setal formula of swimming legs as follows:

P5 (Fig. 2C) with outer seta of baseoendopod arising from setophore. Endopodal lobe triangular with subdistal pore, reaching the middle of exopod; with small outer subdistal and inner proximal spinules, and between apical and subdistal inner seta; with five elements —one outer subdistal, one apical, and one subdistal inner normal setae, and two strongly pectinate inner elements. Exopod oval with subdistal pore; with long slender outer spinules, and small outer spinules; with six elements.

P6 (Fig. 2A) seemingly with one or two outer spinules, with three setae—one short outer pinnate element, and one medial and one inner seta of which medial shorter.

Male. Total body length measured from tip of rostrum to posterior margin of caudal rami 325 µm.

Prosome (not shown) as in female.

Urosome (Figs. 7A, B, 8A) as in female except for second—P6-bearing somite—and third urosomites separated, and for continuous spinular rows of third and fourth urosomites ventrally.

Sexual dimorphism expressed in the ventral somitic ornamentation, antennule, basis of P1, P2 ENP, P5, and P6.

Antennule (Fig. 9A) ten-segmented, haplocer. All segments smooth, except for one proximal and one subdistal spinular row on first segment. All setae smooth except for pinnate seta on first segments, and for four biarticulated setae on ninth and tenth segments. 1(1); 2(10); 3(4); 4(2); 5(6+(1+ae)), 6(2); 7(3); 8(2); 9(4); 10(5+acro). Acrothek consisting of two setae and one aesthetasc fused basally.

Antenna, mandible, maxillule, maxilla and maxilliped (not shown) as in female.

P1 as in female except for comparatively narrower basis without slender inner, long spinules, and for exceedingly long modified inner spine (Fig. 9B), the latter about 0.88 times the length of ENP1, and reaching the tip of EXP3.

P2 EXP (not shown) as in female. Endopod (Fig. 9C) sexually dimorphic, two segmented; ENP1 0.7 times the length of ENP2, with longitudinal row of outer spinules, and with transverse row of inner small spinules close to inner distal acute projection, with outer subdistal pore, armed with one short inner element; ENP2 with longitudinal row of outer spinules, with one inner short medial setae arising from pedestal, distally with long sinuous apophysis with a subdistal rounded extension and seta-like tip, with one posterior strong, blunt element, and with one lateral and one apical seta arising from elongate cylindrical extension fused to segment basally.

P3 and P4 (not shown) as in female.

P5 (Fig. 8B) with outer seta arising from long setophore, the latter ornamented with some spinules; endopodal lobe reaching distal third of exopod, with few inner subdistal small spinules and with longitudinal spinular row along outer margin and close to insertion of exopod; with two inner elements as shown. Exopod small, oval, with outer and inner subdistal spinules as depicted; with five setae.

P6 (Fig. 8C) with three setae each, of which innermost spiniform, medial and outermost slender, medial longest.

Robertgurneya rostrata ( Gurney 1927)

(Figs. 10–18)

Distribution. Barbados: Belair (Coull 1970); Bermuda: Harrington Sound, Trunk Island ( Willey 1935, as A. rostratus ), Bailey’s Bay and Trunk Island ( Coull & Herman 1970); Black Sea: Kolesnikova (1983, 2003).

Egypt: Port Said ( Gurney 1927, as A. rostratus ); Federated States of Micronesia: Yap State, Caroline Islands, Ifaluk atoll ( Vervoort 1964); France: Banyuls ( Monard 1928, as Amphiascus ctenophorus Monard 1928 ); Indian Ocean: Bay of Bengal (Nankauri Harbour, Nicobar Islands) and Arabian Sea (Addu Atoll, Maldive Archipelago) ( Sewell 1940, as A. ctenophorus ); Israel: Gulf of Haifa, Cape Carmel ( Por 1964); Jamaica: Port Royal, Kingston Harbour (Coull 1970); Mexico: Urías coastal system, Mazatlán, Sinaloa State, México: stn 2 (23.1587°N, 106.3326°W; depth 1.8 m; organic carbon content 3.99%; organic matter content 6.86%; sand 80.42%; clay 8.29%; silt 11.28%),

stn 4 (23.184°N, 106.3579°W; depth, 0.7 m; organic carbon content, 1.13%; organic matter content, 1.94%; sand, 82.44%; clay, 8.27%; silt, 9.29%), stn 5 (23.2056°N, 106.3715°W; depth 0.6 m; organic carbon content 0.99%; organic matter content 1.71%; sand 78.61%; clay 6.72%; silt 14.67%), and stn 10 (23.1815°N, 106.4214°W; depth, 6.0 m; organic carbon content, 1.2%; organic matter content, 2.07%; sand, 69.12%; clay, 7.91%; silt, 22.97%) (present study; see also Gómez (2020, Fig. 1); Mozambique: Inhaca Island ( Wells 1967); Turkey: Noodt (1955); USA: Florida (St. George Sound) ( Reidenauer & Thistle 1981; Thistle 1980), off North Carolina ( Coull 1971 b, 1973), US Virgin Islands (St. Thomas) ( Coull 1971a).

Additional uncertain records. Northern Gulf of Mexico ( Baguley 2004, as Robertgurneya aff. rostrata ) .

Material examined. Three dissected females (ICML-EMUCOP-180119-82, ICML-EMUCOP-180119-83, ICML-EMUCOP-180119-84), two dissected males (ICML-EMUCOP-180119-85, ICML-EMUCOP-180119-93), and one female and one male (ICML-EMUCOP-180119-87), nine females, one male, 1 CIV (ICML-EMUCOP- 180119-88), three females, two males, 1 CIV, 1 CV (ICML-EMUCOP-180119-89), 13 females, 11 males, 6 CIII, 2 CIV, 10 CV (ICML-EMUCOP-180119-86), three females (ICML-EMUCOP-180119-90), 1 CV (ICML-EMUCOP- 180119-91), and 13 females, ten males, two CI, one CII, 12 CIII, seven CIV, 23 CV (ICML-EMUCOP-180119-92) preserved in alcohol. Twenty-nine females, 20 males and 5 copepodids were used for molecular analyses .

Description. Female. Total body length measured from tip of rostrum to posterior margin of caudal rami ranging from 485 µm to 620 µm (mean, 554 µm; n, 9); habitus fusiform, widest at posterior end of cephalothorax in dorsal view, tapering posteriad.

Prosome (not shown) as in previous species.

Urosome (Figs. 10A–D, 11A) with general architecture as in previous species; dorsal and lateral surface covered with minutes denticles (omitted in Fig. 10A–D). Spinular ornamentation as follows: first half of genital-double somite with one dorsolateral short row of spinules, second half with one lateral long row of spinules as shown; fourth urosomite with lateral spinular row as in second half of genial-double somite and with additional short row of spinules ventrally; fifth urosomite without spinular ornamentation. Anal somite as in previous species. Caudal rami as in previous species dorsally and laterally; ventrally with transverse row of small spinules between seta VI and large tube pore; caudal setae largely as in previous species; caudal setae IV and V ornamented as shown.

Antennule (Fig. 12A) eight-segmented; all segments smooth, except for one proximal and one subdistal dorsolateral row of spinules on first segment; all setae smooth except for one, three, and one pinnate seta on first, second and third segments, respectively, and for two and four biarticulated setae on seventh and eighth segments, respectively. Armature formula: 1(1); 2(10); 3(7); 4(3+(1+ae)), 5(2); 6(4); 7(4); 8(5+acro). Acrothek consisting of two setae and one aesthetasc fused basally.

Antenna (Fig. 12B) with long outer spinules on small coxa. Allobasis with remains of former division between basis and first endopodal segment, slightly longer than free endopodal segment, with inner long spinules proximally and with two small spinules close to insertion site of exopod; abexopodal seta issuing midway inner margin. Exopod three-segmented; first segment slightly shorter than second and third segments combined, second segment smallest; first and second segments unornamented, with one pinnate seta each; third segment with subapical row of spinules, with three apical setae (one very small element, one spiniform pinnate short seta, and one long pinnate element). Free endopodal segment with proximal and subdistal inner strong spinules, and with two outer frills; armed with two lateral inner spines and two slender setae set close to each other, one inner apical spine, three single geniculate setae, one slender short seta, and one strongly spinulose geniculate outer seta fused basally to slender element.

Mandible (Fig. 13A) with well-developed gnathobasis bearing strong multi- and bicuspidate teeth as shown, with four ventral elements of which ventralmost pinnate and visibly longer. Basis massive, with medial row of spinules, with three pinnate inner setae. Exopod two-segmented; first segment larger than second, with one lateral and one distal seta, second segment with three apical elements of which one visibly thicker. Endopod one-segmented, larger that exopod; with two lateral setae, and distally with one inner seta, and two medial and three outer setae fused basally.

Maxillule (Fig. 13B) with arthrite ornamented with few spinules; with two surface setae, seven distal spines as shown, one spinulose element, and one pinnate ventral seta. Coxal endite with three setae of which one thicker. Basis armed with two lateral, and one subdistal and three distal elements, one of which visibly thicker. Rami one segmented, exopod with two, endopod with four smooth elements.

Maxilla (Fig. 13C) with large syncoxa ornamented with outer spinules as shown; with three endites; proximal endite smallest, with two setae; middle endite with two, distal endite with three setae. Basis drawn out into strong pinnate claw, additionally with strong spine, and one anterior and one posterior slender seta. Endopod two-segmented; first segment with two, second segment with four setae.

Maxilliped (Fig. 13D) subchelate. Coxa elongate, with spinules as shown; with two inner setae issuing subdis- tally one of which visibly shorter, and one distal seta. Basis longer than coxa, elongate, with one posterior and one anterior row of spinules, with one medial and one subdistal inner setae. Endopod one-segmented, elongate, with three setae and apical claw.

P1 (Fig. 14A) with massive coxa ornamented with anterior and posterior spinules as shown. Basis with small spinules medially on anterior face, on inner margin and at base of outer spinulose spine, and with stronger spinules at base of inner spinulose spine and distally on medial extension between rami. Exopod three-segmented, arising at a lower level than the endopod and reaching tip of ENP1; first and third exopodal segments subequal in length, second segment shorter, with spinular ornamentation as shown; first and second segments without inner armature, third segment with four elements. Endopod three-segmented, arising from pedestal; ENP1 elongate, about three times as long as wide, and 1.2 times as long as second and third segments combined, with outer strong and inner slender long spinules, with one inner stiff, long, and strongly pectinate seta arising subdistally; second and third segments with outer spinules as shown, the former with one inner seta; third segment elongate, about six times as long as wide, with one inner distal slender seta, one apical long element, and one outer distal spine.

P2 (Fig. 14B) with triangular praecoxa ornamented with transverse row of small spinules. Coxa with anterior and posterior rows of spinules as shown. Basis with distal inner acute projection; with long inner spinules proximally, with small spinules close to insertion of endopod, and with longer spinules distally on medial extension between rami and at base of outer element. Rami three-segmented; endopod slightly longer than exopod. Exopod arising at a lower level than the endopod, reaching distal third of ENP3; exopodal segments with outer spinules as shown; EXP1 and EXP2 with outer distal acute projection —of EXP1 shorter—, both segments with inner distal hyaline frill; EXP1 without, EXP2 with inner seta; EXP3 with six elements —three outer spines, two apical elements, and one inner seta. Endopod arising from pedestal at a higher level than exopod; endopodal segments with strong outer spinules; ENP1 and ENP2 subequal in length, ENP3 longest; ENP1 with inner distal acute projection, with outer subdistal pore, with distal inner hyaline frill, with one short inner element; ENP2 ornamented as ENP1, but with additional distal outer acute projection, with inner long seta; ENP3 with outer spinular ornamentation, with subdistal pore and with notch midway inner margin between inner seta and inner apical element, with one inner and two apical setae, and one outer spine.

P3 (Fig. 15A) Praecoxa as in P2. Coxa as in P2 but with additional transverse medial row of spinules. Basis as in P2 except for longer outer seta. Rami three-segmented, exopod and endopod subequal in length. Exopod largely as in P2. Endopod largely as in P2 except for two inner setae and lack of inner notch on P3 ENP3.

P4 (Fig. 15B) with praecoxa as in P2 and P3. Coxa as in P3 except for lack of posterior spinules and for additional long proximal spinules posteriorly. Basis as in P3 except for shorter inner proximal spinules. Exopod longer than endopod, largely as in P3 except for two inner setae on P4 EXP3. Endopod reaching distal third of EXP3; largely as in P3 except for one inner seta only on P4 ENP3.

Setal formula of swimming legs as follows:

P5 (Fig. 11C) with outer seta of baseoendopod arising from setophore. Endopodal lobe triangular with subdistal pore, reaching distal fifth of exopod; with small outer and inner spinules; with five elements —two apical, and one subdistal inner normal setae, and two pectinate inner elements. Exopod oval; with small spinules along outer and inner margins; with six elements.

P6 (Fig. 11A) with three setae —one short outer pinnate element, and one medial and one inner seta of which medial shorter.

Male. Total body length measured from tip of rostrum to posterior margin of caudal rami ranging from 335 µm to 450 µm (mean, 395 µm; n, 4).

Prosome (not shown) as in female.

Urosome (Figs. 16A, B, 17A) as in female except for second —P6-bearing somite— and third urosomites separated, and for continuous spinular rows of third and fourth urosomites ventrally.

Sexual dimorphism expressed in the ventral somitic ornamentation, antennule, basis of P1, P2 ENP, P5, and P6.

Antennule (Fig. 18A) ten-segmented, haplocer. All segments smooth, except for two spinular rows on first segment. All setae smooth except for one, three and one pinnate seta on first, second and third segments, and for three and four biarticulated setae on ninth and tenth segments. Armature formula as follows: 1(1); 2(10); 3(8); 4(1); 5(6+1 modified+(1+ae)), 6(2); 7(1); 8(2); 9(4); 10(5+acro). Acrothek consisting of two setae and one aesthetasc fused basally.

Antenna, mandible, maxillule, maxilla and maxilliped (not shown) as in female.

P1 as in female except for comparatively narrower basis, and for modified inner spinulose spine with curved tip (Fig. 18B), the latter about 0.67 times the length of ENP1, and as long as EXP1 and EXP2 combined.

P2 EXP (not shown) as in female. Endopod (Fig. 18C) sexually dimorphic, two segmented; ENP1 0.6 times the length of ENP2, with longitudinal row of outer spinules, and with transverse row of inner small spinules close to inner distal acute projection, with outer subdistal pore, armed with one short inner element; ENP2 with longitudinal row of long, slender, outer spinules, with one inner long medial setae arising from pedestal, distally with long sinuous apophysis with a subdistal rounded extension and seta-like tip, with one posterior strong, blunt element, and with one lateral and one apical seta arising from elongate cylindrical extension fused to segment basally.

P3 and P4 (not shown) as in female.

P5 (Fig. 17B) with outer seta arising from setophore; endopodal lobe reaching slightly beyond exopod, with few inner small subdistal and comparatively stronger outer spinules as shown; with two inner elements. Exopod small, circular, with outer proximal and distal spinules, with six setae.

P6 (Fig. 17C) with three setae each, of which medial longest.

CV

Municipal Museum of Chungking