Boreomysis californica Ortmann, 1894

Hernández-Payán, J. C. & Hendrickx, M. E., 2024, The genus Boreomysis G. O. Sars, 1869 (Peracarida, Mysida, Mysidae) in western Mexico, Zootaxa 5418 (5), pp. 501-527 : 513-523

Boreomysis californica Ortmann, 1894

( Figures 10‒16 )

Boreomysis californica Ortmann 1894: 106 , figs. 4‒14.— Banner 1948: 367‒369, pl. IV, fig. 5a‒i; 1954: 579.—W.M. Tattersall 1951: 52‒55, figs. 9‒10.— Gordan 1957: 342 (list, complete synonymy).— Birstein & Tchindonova 1958: 294; 1962: 64, fig. 5.— Ii 1964: 610.— Taniguchi, 1969: 46‒47, fig. 4a‒d.— Childress & Nygaard 1974: 228 (chart).— Mauchline & Murano 1977: 88 (catalogue).— Austin 1985: 560 (list).— Kathman et al. 1986: 416.— Laubitz 1986: 15.— Ikeda 1991: 100 (table).— Müller 1993: 24 (list).— Price 2004: 56 (list).— Rinewalt et al. 2007: 46 (table).— San Vicente 2018: 125 (table).— Hernández-Payán & Hendrickx 2020: 52 (table 1).

Boreomysis media Hansen, 1912: 190 , pl. 1, fig. 2a‒b.

Boreomysis kincaidi Banner, 1948: 362‒365 , pl. 2, fig. 3a‒j.

Material examined 93 males; 250 females. No ovigerous females.

TALUD IV. St. 7 (22°00’22” N, 106°49’18’’ W), August 23, 2000, 5 females (CL 2.50‒6.65 mm), MN between surface and 500 m, 1970 m total depth ( ICML-EMU-12541 ); St. 15 (23°23’30” N, 107°47’48” W), August 24, 2000, 2 females (CL 2.19, 3.97 mm), MN between surface and 1500 m, 2350 m total depth ( ICML-EMU-12542-A ); St. 22 (24°17’20” N, 108°50’30” W), August 26, 2000, 1 male (CL 3.85 mm) and 2 females (CL 5.94, 6.33 mm), MN between surface and 1325 m ( ICML-EMU-12542-B ); St. 29 (24°57’48” N, 109°37’00” W), August 27, 2000, 3 females (CL 3.72‒4.49 mm), MN between surface and 1280 m, 2080 m total depth ( ICML-EMU-12542-C ); St. 35 (25°53’59” N, 110°11’17” W), August 27, 2000, 1 male (CL 7.10 mm), BS operated at 2000‒2100 m ( ICMLEMU-12542-D ); St. 36 (25°51’59” N, 110°11’00” W), August 27, 2000, 1 male (CL 6.97 mm) and 8 females (CL 2.55‒8.27 mm), MN between surface and 1000 m, 2100 m total depth ( ICML-EMU-12543 ).

TALUD V. St. 15 (23°21’30” N, 107°48’12” W), December 14, 2000, 6 females (CL 2.01‒8.07 mm), MN between surface and 1350 m, 2384 m total depth ( ICML-EMU-12544-A ); St. 29 (25°14’36” N, 109°24’15” W), December 17, 2000, 1 male (CL 8.57 mm) and 11 females (CL 3.21‒7.66 mm), MN between surface and 1290 m, 2040 m total depth ( ICML-EMU-12544-B ); St. 36 (25°54’30” N, 110°11’24” W), December 17, 2000, 4 males (CL 5.56‒9.11) and 8 females (CL 2.98‒7.38 mm), MN between surface and 1340 m, 1990 m total depth ( ICML-EMU-12545 ).

TALUD VI. St. 7 (22°21’39” N, 107°01’42” W), March 14, 2001, 2 males (CL 4.82, 4.93 mm) and 4 females (CL 2.89‒6.67 mm), MN between surface and 1305 m, 2100 m total depth ( ICML-EMU-12546-A ); St. 22 (24°17’26” N, 108°50’05” W), March 15, 2001, 1 male (CL 5.06 mm) and 6 females (CL 2.03‒3.17 mm), MN between surface and 1500 m ( ICML-EMU-12546-B ); St. 26 (24°56’18” N, 109°06’42” W), March 16, 2001, 1 female (CL 8.07 mm), BS operated at 1190‒1270 m ( ICML-EMU-12547 ); St. 29 (25°16’24” N, 109º24’54” W), March 16, 2001, 4 males (CL 2.80‒9.34 mm) and 8 females (CL 2.01‒5.10 mm), MN between surface and 1440 m, 2080 m total depth ( ICML-EMU-12548 ); St. 36 (25°53’15” N, 110°10’08” W), March 17, 2001, 19 females (CL 2.01‒8.31 mm), MN between surface and 1360 m, 2000 m total depth ( ICML-EMU-12549 ).

TALUD VII. St. 5 (22°00’24” N, 106°39’54” W), June 5, 2001, 1 male (CL 6.53 mm), BS operated at 1490‒1520 m ( ICML-EMU-12550-A ); St. 12 (23°18’18” N, 107°26’48” W), June 6, 2001, 1 male (CL 7.44 mm), BS operated at 1040‒1220 m ( ICML-EMU-12550-B ); St. 15-B (23°25’19” N, 107°46’25” W), June 7, 2001, 3 females (CL 2.70‒4.47 mm), MN between surface and 1425 m, 2320 m total depth ( ICML-EMU-12550-C ); St. 19 (24°16’12” N, 108°23’42” W), June 7, 2001, 1 female (CL 6.84 mm), BS operated at 1160‒1180 m ( ICML-EMU-12550-D ); St. 22 (24°31’34” N, 108°55’10” W), June 7, 2001, 1 male (CL 5.86 mm), MN between surface and 1415 m, 2000 m total depth ( ICMLEMU-12551-A ); St. 27 (25°01’30” N, 109°12’00” W), June 8, 2001, 2 males (CL 7.44, 7.86 mm), BS operated at 1580‒1600 m ( ICML-EMU-12551-B ); St. 29 (25°17’32” N, 109°24’30” W), June 8, 2001, 2 males (CL 5.47, 5.54 mm) and 8 females (CL 2.21‒7.47 mm), MN between surface and 1335 m, 2080 m total depth ( ICML-EMU-12551- C ); St. 33-B (26°06’30” N, 110°06’42” W), June 9, 2001, 2 females (CL 7.21, 8.00 mm), BS operated at 1260‒1300 m ( ICML-EMU-12552-A ); St. 36 (25°42’37” N, 110°04’35” W), June 9, 2001, 1 male ( CL 7.74 mm) and 9 females (CL 2.59‒7.57 mm), MN between surface and 1390 m, 2400 m total depth ( ICML-EMU-12552-B ).

TALUD VIII. St. 10 (24°58’12” N, 110°16’06” W), April 17, 2005, 1 male (CL 7.63 mm) and 1 female (CL 7.62 mm), BS operated at 1500 m ( ICML-EMU-12553-A ); St. 15 (25°23’06” N, 110°18’24” W), April 18, 2005, 4 males (CL 7.95‒10.12 mm) and 1 female (CL 8.18 mm), BS operated at 2100 m ( ICML-EMU-12553-B ); St. 17-B (25°24’24” N, 110°50’06” W), June 9, 2001, 2 males (CL 9.10, 10.77 mm) and 12 females (CL 6.73‒9.75 mm), BS operated at 700‒750 m ( ICML-EMU-12554-A ); St. 20 (25°56’56” N, 110°43’00” W), April 19, 2005, 1 female (CL 7.13 mm), BS operated at 1140‒1150 m ( ICML-EMU-12554-B ); St. 22 (26°03’42” N, 110°23’54” W), April 19, 2005, 8 males (CL 6.04‒11.06 mm) and 5 females (CL 7.32‒8.25 mm), BS operated at 2200 m ( ICML-EMU-12555 ).

TALUD IX. St. 2 (24°38’42” N, 109°17’36” W), November 11, 2005, 6 males (CL 5.74‒10.57 mm) and 9 females (CL 6.07‒10.34 mm), BS operated at 2195‒2300 m ( ICML-EMU-12556-A ); St. 3 (24°32’52” N, 109°29’04” W), November 11, 2005, 1 male (CL 6.63 mm), BS operated at 1454‒1620 m ( ICML-EMU-12556-B ); St. 14 (25°31’30” N, 110°07’24” W), November 14, 2005, 4 males (CL 8.21‒9.87 mm) and 7 females (CL 9.14‒10.47 mm), BS operated at 2010‒2240 m ( ICML-EMU-12557-A ); St. 15 (25°21’27” N, 110°18’18” W), November 13, 2005, 3 males (CL 8.69‒9.36 mm) and 5 females (CL 7.23‒9.42 mm), BS operated at 1985‒2290 m ( ICML-EMU-12557- B ); St. 21-B (26°04’42” N, 110°34’48” W), November 14, 2005, 1 female (CL 8.94 mm), BS operated at 1349‒1369 m ( ICML-EMU-12557-C ); St. 22 (26°03’42” N, 110°20’36” W), November 14, 2005, 1 male (CL 9.49 mm) and 2 females (CL 7.91, 9.31 mm), BS operated at 2214‒2309 m ( ICML-EMU-12558 ).

TALUD X. St. 7 (27°53’09” N, 112°16’42” W), February 10, 2007, 4 males (CL 4.81‒6.85 mm) and 7 females (CL 2.06‒5.62 mm), MN between surface and 900 m, 1191 m total depth ( ICML-EMU-12559 ); St. 8 (28°05’56” N, 112°26’50” W), February 10, 2007, 3 males (CL 7.23‒7.61 mm) and 15 females (CL 4.58‒8.61 mm), BS operated at 975‒1007 m ( ICML-EMU-12560 ); St. 9 (27°52’51” N, 112º15’53” W), February 10, 2007, 5 males (CL 6.61‒7.97 mm) and 13 females (CL 6.87‒7.92 mm), BS operated at 1205‒1215 m ( ICML-EMU-12561-A ); St. 11 (27°34’16” N, 111°40’30” W), February 11, 2007, 1 male (6.10 mm) and 5 females (CL 3.43‒7.59 mm), MN between surface and 1220 m, 1800 m total depth ( ICML-EMU-12561-B ); St. 17 (27°08’00” N, 111°44’10” W), February 12, 2007, 3 males (CL 7.29‒9.55 mm) and 9 females (CL 6.71‒8.00 mm), BS operated at 1289‒1326 m ( ICML-EMU-12562 ); St. 18 (27°09’06” N, 111°46’54” W), February 12, 2007, 5 males (CL 7.27‒9.38 mm) and 5 females (CL 7.77‒9.92 mm), BS operated at 1526 m ( ICML-EMU-12563-A ); St. 20 (27°14’41” N, 111°36’15” W), February 13, 2007, 2 males (CL 8.83, 9.68 mm) and 8 females (CL 2.79‒8.36 mm), MN between surface and approx. 1250 m, 1785 m total depth ( ICML-EMU-12563-B ); St. 22 (27°14’31” N, 111°14’39” W), February 13, 2007, 4 males (CL 6.99‒9.99 mm) and 4 females (CL 6.22‒8.66 mm), BS operated at 1864‒1865 m ( ICML-EMU-12564-A ); St. 23 (27°00’30” N, 111°12’00” W), February 14, 2007, 3 males (CL 5.00‒ 9.67 mm) and 3 females (CL 3.67‒6.83 mm), MN between surface and approx.. 1250 m, 1770 m total depth ( ICML-EMU-12564-B ).

TALUD XI. St. 6-A (16°58’00” N, 100°57’00” W), June 7, 2007, 4 females (CL 2.41‒6.74 mm), MN between surface and 1400 m, 1960 m total depth ( ICML-EMU-12565 ); St. 19-B (17°56’00” N, 103°10’00” W), June 9, 2007, 1 male (CL 7.54 mm) and 9 females (CL 2.73‒6.74 mm), MN between surface and 1490 m, 1750 m total depth ( ICML-EMU-12566 ).

TALUD XII. St. 4 (16°59’39” N, 100°58’07” W), March 28, 2008, 2 males (CL 4.74, 6.22 mm) and 2 females (CL 2.25, 6.62 mm), MN between surface and 1200 m, 1995 m total depth ( ICML-EMU-12567-A ); St. 9 (17°10’26” N, 101°37’37” W), March 29, 2008, 1 male (CL 9.46 mm) and 1 female (CL 6.11 mm), BS operated at 1392‒1420 m ( ICML-EMU-12567-B ); St. 15-C (17°27’51” N, 102°10’43” W), March 31, 2008, 2 females (CL 2.74, 3.93 mm), MN between surface and 1530 m, 1880 m total depth ( ICML-EMU-12567-C ); St. 22 (18°11’27” N, 103°52’29” W), March 31, 2008, 1 male (CL 5.51 mm) and 1 female (CL 4.65 mm), MN between surface and 1340 m, 2200 m total depth ( ICML-EMU-12568-A ); St. 28-B (18°56’00” N, 104°59’57” W), April 2, 2008, 2 males (CL 5.39, 5.61 mm) and 6 females (CL 2.68‒4.82 mm), MN between surface and 1425 m, 2041 m total depth ( ICML-EMU-12568-B ).

TALUD XIII. St. 34 (26°33’36” N, 111°02’00” W), January 14, 2009, 1 female (CL 8.49 mm), AD operated at 1485‒1530 m ( ICML-EMU-12569-A ); St. 36 (26°07’12” N, 110°30’53” W), January 15, 2009, 1 female (CL 9.40 mm), AD operated at 2300‒2360 m ( ICML-EMU-12569-B ).

TALUD XV. St. 5-C (23°16’42” N, 110°54’55” W), August 5, 2012, 1 male (CL 7.59 mm), BS operated at 980‒1036 m ( ICML-EMU-12570-A ); St. 9 (24°25’12” N, 112°52’48” W), July 30, 2012, 1 female (CL 8.48 mm), BS operated at 1425‒1494 m ( ICML-EMU-12570-B ); St. 17 (26°20’24” N, 114°13’07” W), July 31, 2012, 1 female (CL 8.78 mm), BS operated at 2111‒2136 m ( ICML-EMU-12570-C ); St. 24 (27°05’42” N, 114°35’30” W), August 1, 2012, 1 female (CL 7.19 mm), BS operated at 772‒786 m ( ICML-EMU-12571 ).

TALUD XVI-B. St. 26 (31°46.1” N, 116°58.35” W), May 27, 2014, 1 female (CL 7.39 mm), BS operated at 982‒989 m ( ICML-EMU-12572-A ); St. 27 (31°42.6” N, 117°13” W), May 27, 2014, 2 males (CL 6.55, 7.77 mm), BS operated at 1394‒1397 m ( ICML-EMU-12572-B ).

Description. Carapace ( Fig. 10A, C ) elongated, produced anteriorly to form a subtriangular rostrum ending in an acute point, reaching about 0.5 times length of antennula first article; anterolateral margins sharply produced; cervical sulcus well marked dorsally, posterodorsal margin reaching to about mid-length of ultimate thoracic segment.

Eyes ( Fig. 10B ) small, subcylindrical, cornea as wide as ocular peduncle distal end, well marked, antero-dorsal, triangle-shape tubercle.

Antennular peduncle ( Fig. 10D ) robust; article 1 rectangular, longer than articles 2 and 3 combined, 4 short setae in middle of outer margin, inner margin with 5 longer setae, 2 longer setae on inner, distal corner; article 2 smallest, 3 long setae on outer distal corner; article 3 almost as wide as long, 8 long setae on distal outer margin, distal margin with small protuberance with 3 short setae in middle of flagella.

Antennal peduncle ( Fig. 10E ) about 2/3 the length of the scale; article 1 short, with prominent thorn on inner margin; article 2 longest, 2 times as long as 1 or 3, approximately 1/3 times scale, 2 distal setae on outer margin, 1 distal seta on inner margin; article 3 similar in size to article 1, 7 distal setae in outer margin, 3 distal setae in inner margin. Antennal scale ( Fig. 10E ) moderately long, extending beyond distal edge of antennal peduncle by about 0.5 its length, about 3 times as long as wide, outer margin slightly convex, without setae, inner margin setose; apical tooth well-marked, its tip reaching to the level of scale apex; no distal suture.

Labrum ( Fig. 11A ) symmetrical, posterior margin slightly bilobed, with short, simple setae (left) and finely pitted (right).

Mandibles ( Fig. 11B , 12A‒F ) with long, broad palp; first article short, without spines; second longer than third, broad in its proximal part, both margins setose; third article approximately 4 times as long as wide, short comb-shaped setae on distal inner margin, numerous long, plumose setae, outer margin with 5 thin setae. Right mandible ( Fig. 12A‒C ) well developed, with reduced incisive process, comprised of 1 chitinous ridge with 4 teeth; lacinia mobilis reduced, located between incisive and pars centralis, represented by 1 set of small spinal setae; pars centralis formed by 1 row of long and thick apical setae as well as 1 series of small and thin setae that cover both base of the molar process and external margins ( Fig. 12B ); molar process subrectangular, with 1 series of parallel lamellae on crushing surface formed by short sharp spines attached at base, 1 series of small pores at edge of molar process. Left mandible ( Fig. 11B , 12 D‒F ) incisor process composed of 1 chitinous ridge with 4 teeth; lacinia mobilis well developed, consisting of 4 teeth, 2 extremes stronger, prominent, 1 bifid, 2 central teeth smaller; pars centralis represented by series of 6 lamellae with slightly narrower base, margins spiny; molar process similar to right mandible.

Maxillula ( Fig. 11C ) external lobe armed with 12 robust, indented, apical setae, 9 long plumose setae on ventral surface; inner lobe with 5‒7 long apical setae, 7 plumose setae on inner margin, 5 short simple setae on outer margin, and 7 short setae on ventral surface.

Maxilla ( Fig. 11D ) with narrow, tapering exopod, armed with 40 or 41 simple marginal setae; proximal article of endopodite with 6 simple setae, distal article circle-shaped, densely setose on both margins, setae long, plumose; 3 subrectangular endites, distal margins with plumose setae; protopod with dense covering of long, plumose setae.

Thoracopod 1 ( Fig. 13A ) short, thin; gnathobase of endopod with well developed, elongated lobe, 1 series of long plumose setae on outer margin, 5‒7 short, plumose setae on distal edge; pre-ischium with 9 plumose setae; ischium with 5 long, plumose setae on inner margin, 6 single setae on outer margin; merus elongated, with 14 long, plumose setae on inner margin, several single setae on outer margin and on ventral surface; carpo-propodus short, with 5 simple setae on inner margin, several single setae on outer margin, and few setae on ventral surface; dactylus short, triangular with several long and thin setae on margins and ventral face; nail curved, slightly shorter than dactylus, distal with setulae; exopod almost 2 times as long as endopod, 22-articulated, each article with long plumose setae.

Thoracopod 2 ( Fig. 13B ) endopod longer than first, shorter than 3 and 4; endopod elongated, not distally subchelate; short, naked pre-ischium; ischium armed with long, simple setae on both margins; merus and carpo-propodus armed with 1 series of long, simple setae on inner margin; dactylus with numerous simple setae, 1 series of short, serrated setae on inner margin; exopod slightly shorter than endopod, 24-articulated, each article with long, plumose setae.

Thoracopod 3‒8 ( Figs. 13 C‒D , 14 A‒D ) similar; elongated endopods; pre-ischium naked; ischium armed with long simple setae on both margins; merus armed with simple setae on inner margin; carpus with 1 series of long and short setae on inner margin; propodus divided into 2 subsegments, proximal shorter than distal; dactyl and nail forming long claw; exopod slightly shorter than endopod, 24-articulated, each article with long, plumose setae.

Penis ( Fig. 14E ) elongated, about 2 times as long as wide; distal portion with tiny tubercles and short setae.

Abdominal somites ( Fig. 10A ) 1‒6 without spines.

Male pleopods ( Fig. 15A‒E ) biramous, well developed; exopods multi-articulated (9‒21 articles), without marginal setae, exopod of pleopod 2 equal in length to exopod, of pleopod 3 longer, of pleopods 4‒5 shorter; first pleopod endopod uniarticulated, a well developed, elongated, rectangular lobe, about 2/3 the length of the corresponding endopod, short pseudobranchial lobe proximally with four simple setae, rest of the endopod with 11 long plumose setae on outer margin, distal setae diminishing in length. Pleopods 2‒5 endopods multi-articulated (11‒14 articles), basal article long, almost 1/2 length of entire endopod, proximal pseudobranchial lobe short, with 4‒6 long, simple setae, inner margin covered with long plumose setae.

Uropods ( Fig. 16A ) long, thin; exopod about 1.3 times telson length, almost 7 times as long as wide, about 1.2 times as long as endopod, outer margin armed with 1 short proximal seta; endopod about 6 times as long as greatest width, armed with one long, robust seta on inner margin.

Telson ( Fig. 16B ) linguiform, about 3.5 times as long as wide, maximum width about 2.8 times minimum width; margins proximal 1/3 naked, remaining 2/3 with 45‒49 setae, including long setae and intermediate clusters of 2 or 3 short setae; distal cleft ( Fig. 8D‒F ) V-shaped, deep, approximately 1/5 to 1/6 of total telson length; base of cleft narrowing, V-shaped, with short basal slit; inner margins of cleft armed each with 29‒31 robust setae, setae increasing in size towards distal part of cleft, spine-like, closely set, articulated at base; 3 long, robust setae on each terminal lobe, outer seta longest.

Females. Marsupium of females comprised of 7 pairs of oostegites. Female pleopods ( Fig. 15 F-J) uniramous, well developed, increasing in size posteriorly, covered with long, plumose setae on inner margin.

Size (Material examined). Males, CL 2.80‒11.06 mm; females, CL 2.01‒10.47 mm.

New records in Mexico. Review of collections data bases at the Smithsonian Institution ( USNM), at Scripps, La Jolla, at the Los Angeles County Museum of Natural History, and at the Museum of Comparative Zoology, Harvard, failed to disclose records in western Mexico other than the type locality. Boreomysis californica is now recorded in 58 new locations in western Mexico: 43 localities in the center and south of the Gulf of California, six off the west coast of the Baja California Peninsula, and nine off the SW coast of Mexico ( Fig. 17 ) thus indicating it is a widespread and very frequent species in the region. Hernández-Payán & Hendrickx (2020) briefly included B. californica in a list of species of mysids known to occur in western Mexico, referring to the same material reported in detail herein.

Geographic distribution. 50 miles south of Guaymas, Gulf of California (type locality) ( Ortmann 1894), and at 20°25’N, 105°42’W, in SE Gulf of California ( Brusca & Hendrickx 2008 onwards); off California, off Peru, Okhotsk Sea, Bering Sea, off British Columbia; Indian and Atlantic Oceans (as Boreomysis media Hansen, 1912 ; Illig 1930). Widely distributed in eastern Pacific, from Bering Sea to British Columbia and south to Peru. Only two previous record for Mexican Pacific: south of Guaymas and near southern entrance to Bahía Banderas. Now recorded as widely spread off western Mexico ( Fig. 17 ) (this study).

Bathymetric distribution. Because stratified (discrete) samples were not available during our study, the specimens examined herein were collected at unknown depths during sampling operations within the water column, from surface to 700‒2309 m ( BS), to 1485‒2360 (AD), and to 1530 ( MN). Childress & Nygaard (1974) reported the occurrence of B. californica off southern California and estimated that it ranged from a minimum depth of 500 m to a maximum depth of> 1100 m (rough estimates where most of the population was found). According to Mauchline & Murano (1977) B. californica is considered a bathypelagic species.

Remarks. The material examined fit well with the illustrations provided by Banner (1948) and W.M. Tattersall (1951): eye with large cornea and well-marked triangular process on the upper surface ( Banner 1948: plate IV: 5d; W.M. Tattersall 1951: fig. 10a), rostrum with obtuse spine reaching to approximately 1/3 length of first article of antennular peduncle (W.M. Tattersall 1951: fig. 9b); antennal scale in our material ( Fig. 10E ) is about 3 times as long as wide, similar to what is reported by Banner (1948: plate IV, fig. 5 e) and W.M. Tattersall (1951: fig. 10b); shape and proportions of the telson, with a somewhat V-shaped basal portion of cleft ( Fig. 8D‒F , 16B ), somewhat similar to that illustrated by Banner (1948: plate IV: 5 a‒b) and W.M Tattersall (1951: fig. 10f).

Boreomysis californica differs from the other species recorded in the eastern Pacific by one or several of the following characters: antennal scale moderately long and wide, outer margin slightly convex and with an apical tooth well-marked, without distal suture; eye small, sub-cylindrical and with a antero-dorsal, triangle-shape tubercle, well-developed; telson linguiforme, distal cleft V-shaped deep and well-marked, and with 3 long, robust setae on each terminal lobe.

Figures

FIGURE 8. A‒C, Boreomysis arctica (Krøyer, 1861). Male (CL 11.07 mm; TL, 27.42 mm) (ICML-EMU-12577-B); D‒F, Boreomysis californica Ortmann, 1894. Female (CL 10.21 mm; TL 18.73 mm) (ICML-EMU-12544-A). A, D, distal part of telson, dorsal view; B, E, same, enlarged cleft; C, F, same, enlarged basal part of cleft.

FIGURE 10. Boreomysis californica Ortmann, 1894. Female (CL 10.21 mm; TL 18.73 mm) (ICML-EMU-12544-A).A, lateral view; B, left eye, dorsal view; C, cephalothorax with appendages, dorsal view; D, antennula, lateral view; E, antennal peduncle with scale, dorsal view.

FIGURE 11. Boreomysis californica Ortmann, 1894. Female (CL 10.21 mm; TL 18.73 mm) (ICML-EMU-12544-A). A, labrum, with magnification of posterior margin (arrow); B, left and right mandibles with mandibular palp; C, maxillula with magnification of external lobe seta (arrow); D, maxilla.

FIGURE 12. Boreomysis californica Ortmann, 1894. Female (CL 10.21 mm; TL 18.73 mm) (ICML-EMU-12544-A). A‒C, right mandible; D‒F, left mandible.

FIGURE 13. Boreomysis californica Ortmann, 1894. Female (CL 10.21 mm; TL 18.73 mm) (ICML-EMU-12544-A). A, thoracopod 1 with magnification of distal articles (arrow); B, thoracopod 2 with magnification of distal articles (arrow); C, thoracopod 3; D, thoracopod 4.

FIGURE 14. Boreomysis californica Ortmann, 1894. A‒D, female (CL 10.21 mm; TL 18.73 mm); E, male (CL 10.70 mm; TL 25.11 mm) (ICML-EMU-12554-A). A, thoracopod 5; B, thoracopod 6, with magnification of dactylus (arrow); C, thoracopod 7; D, thoracopod 8; E, penis.

FIGURE 15. Boreomysis californica Ortmann, 1894. A‒E, male (CL 10.70 mm; TL 25.11 mm) (ICML-EMU-12554-A); F‒J, female (CL 10.21 mm; TL, 18.73 mm) (ICML-EMU-12554-A). A‒E, pleopods 1 to 5; F‒J, pleopods 1 to 5.

FIGURE 16. Boreomysis californica Ortmann, 1894. Female (CL 10.21 mm; TL 18.73 mm) (ICML-EMU-12554-A). A, uropodal endopod and exopod, dorsal view; B, telson, dorsal view, with magnification of distal cleft basal part (arrow).

FIGURE 17. Localities in western Mexico where B. californica Ortmann, 1894 was collected during this study.