On a small collection of Laophontidae T. Scott (Copepoda: Harpacticoida) from Mexico. I. New species and new records of Laophonte Philippi and Paralaophonte Lang Gómez, S. Morales-Serna, F. N. Journal of Natural History 2013 2013-02-11 47 5 - 12 329 380 Gómez & Morales-Serna, 2013 Gómez & Morales-Serna 2013 [478,814,1644,1669] Hexanauplia Laophontidae Paralaophonte Animalia Harpacticoida 36 363 Arthropoda species pacificavicinum sp. nov.  ( Figures 30–37)    Material examined One female holotype(EMUCOP-021205-04) and one male allotype(EMUCOP- 021205-05) preserved in alcohol. Paratypespreserved in alcohol: two femalesand  Figure 27.  Paralaophonte pacificaemulator sp. nov., male. (A) Urosome, ventral; (B) urosome, dorsal. Scale bars: A, B, 100 µm.  two males(EMUCOP-020591-05), one femaleand four males(EMUCOP-021205-06), one femaleand one male(EMUCOP-080205-20), one adultmale (EMUCOP-080205- 21), four females(EMUCOP-080205-22), two males(EMUCOP-090301-36), three femalesand two males(EMUCOP-090301-37), and  two females(EMUCOP-160506- 01). Dissected paratypes: three males(EMUCOP-021205-07, EMUCOP-021205-08, EMUCOP-090301-38),  four females(EMUCOP-021205-09, EMUCOP-021205-10, EMUCOP-021205-11, EMUCOP-090301-47), and one CIII(EMUCOP-090301-46). Collected from Ensenada del Pabellónlagoon ( Sinaloa State, north-western Mexico) (24 ◦19 ′– 24 ◦35 ′N, 107 ◦28 ′– 107 ◦45 ′W), stn. 3 (see Gómez-Noguera and Hendrickx  Figure 28.  Paralaophonte pacificaemulator sp. nov., male. (A) Antennule; (B) P1; (C) P2 ENP. Scale bars: A–C, 50 µm.  1997, for more information regarding nitrogen and carbon content and sediment type), brackish, less than  2 mdepth,  2 May 1991; from Urías System( Sinaloa State, northwestern Mexico) ( 23 ◦11 ′06 ′′N, 106 ◦25 ′06 ′′W), stn. 3, 4, 5, and 9 (see Morales-Serna Figure 29.  Paralaophonte pacificaemulator sp. nov., male. (A) P3; (B) P4; (C) P5; (D) P6. Scale bars: A–D, 50 µm. et al. 2006, for more information regarding organic matter content, chlorophyll acontent and sediment type), brackish, less than 2 mdepth, 9 March 2001, 2 December and 8 February 2005, coll. S. Gómez (Ensenada del Pabellón lagoon) and F. N. Morales-Serna, F. E. Vargas-Arriaga and S. Gómez (Urías System).    Typelocality   Urías System( Sinaloa State, north-west Mexico) ( 23 ◦11 ′06 ′′N, 106 ◦25 ′06 ′′W).   Other localities   Ensenada del Pabellónlagoon ( Sinaloa State, north-west Mexico) (24 ◦19 ′– 24 ◦35 ′N, 107 ◦28 ′– 107 ◦45 ′W), off Campeche State, Gulf of Mexico(south-east Mexico) ( 19 ◦18 ′55.20 ′′N, 91 ◦06 ′59.52 ′′W).    Etymology The specific epithet  pacificavicinum(  pacificaafter  P. pacifica; Latin, vicinum, neighbour) makes reference to the strong resemblance to  P. pacifica.    Description  Female.Habitus fusiform ( Figure 30A, B). Total body length measured from tip of rostrum to posterior margin of caudal rami ranging from 425 µm to 490 µm (mean = 449 µm; n= 7). Rostrum fused to cephalic shield, triangular, with bilobed tip flanked by pair of sensilla. Cephalothorax dorsally and laterally as shown ( Figure 30A, B), with posterior margin minutely serrate dorsally, with setules along posterior margin dorsally and laterally. P2–P5-bearing somites covered with tiny spinules, with posterior margin minutely serrate, with setules along posterior margin dorsally and laterally. Genital double-somite ( Figures 30A, B, 31A, B) distinct dorsally and laterally; fused ventrally; both halves of the genital double-somite with posterior margin minutely serrate, first half with posterior spinules and without setules, second half with setules but without spinules, lateral expansions moderately developed, and with sets of spinules; posterior half of genital-double somite (third urosomite) with spinules along posterior margin ventrally. Fourth and fifth urosomites as previous somite dorsally; fourth urosomite with, fifth urosomite without lateral expansions; both urosomites with small spinules along posterior margin. Anal somite ( Figures 31A, B, 32A) covered with tiny spinules dorsally, with spinules along posterior margin dorsally and ventrally; rounded anal operculum with minutely serrate posterior margin and flanked by pair of sensilla. Caudal rami ( Figures 31A, B, 32A) about 1.2 times as long as wide; covered with tiny spinules dorsally and laterally, and with stronger spinules ventrally along posterior margin ( Figure 31B); with seven elements; seta I very small (arrowed in Figure 32A), situated ventrally to seta II, both situated on distal fifth along lateral margin; seta III longer than seta II and situated almost at the same level, ventrally to seta II and posterior to seta I; seta IV pinnate; seta V longest; seta VI arising from inner distal corner, nearly as long as seta II; seta VII situated dorsally, on the distal third of the inner margin, triarticulated. Antennule ( Figure 33A) six-segmented; first segment with medial and distal inner spinules, without process; second segment with some inner spinules proximally, with acute conical outer process; third segment with some transverse rows of minute spinules along outer margin medially and distally; fourth and fifth segments small, each with spinular outer row; sixth segment elongate, about three times as long as wide, with outer spinular row proximally. Armature formula, I-(1); II-(8); III-(7); IV-(2 + ae); V-(1); VI-(9 + acrothek) (acrothek consisting of two setae and one aesthetasc fused basally). Antenna ( Figure 33B). Allobasis with one small, unipinnate abexopodal seta, and with inner spinules proximally. Exopod one-segmented, with two lateral (proximal one longer, bare and slender) and two distal elements. Free endopodal segment with inner row of spinules, with two outer frills, and with two spines and a slender seta laterally, and apically with two strong spines, two geniculate single setae and one geniculate seta fused to tiny element basally. Mandible ( Figure 33C). Strong gnathobase with bi- and multicuspidate teeth distally and one pinnate seta laterally. Palp one-segment, with five seta (one basal, one exopodal, three endopodal). Maxillule ( Figure 33D). Arthrite with some spinules as depicted, with five strong apical spines and one lateral element. Coxa with two setae. Basis with three apical elements (one of them stronger). Exopod one-segmented, elongate, with two setae. Endopod small, one-segmented, with three setae.  Figure 30.  Paralaophonte pacificavicinum sp. nov., female. (A) Habitus, dorsal; (B) habitus, lateral. Scale bars: A, B, 200 µm.  Figure 31.  Paralaophonte pacificavicinum sp. nov., female. (A) Urosome, dorsal (P5-bearing somite omitted); (B) urosome, ventral (P5-bearing somite omitted). Scale bars: A, B, 50 µm. Maxilla ( Figure 33E). Syncoxa with outer and inner spinules as shown; with three endites; proximal endite with one seta, middle and distal endites with three elements as figured (one of them fused to endite basally). Allobasis drawn into strong claw with three accessory setae. Endopod represented by two setae. Maxilliped ( Figure 33F). Syncoxa with spinular rows as depicted, with two distal setae. Basis with small outer spinules; endopod drawn out into claw with one accompanying seta. P1 ( Figure 34A). Coxa with several spinule rows as figured. Basis with longitudinal row of spinules, with inner and outer spine-like element. Exopod three-segmented, not reaching to middle of ENP1. Endopod two-segmented, elongate; ENP1 long, about 6.6 times as long as wide, with inner setules; ENP2 about twice as long as wide, with outer and apical spinules, with one small apical seta and one strong claw, the latter about 2.1 times as long as supporting segment.  Figure 32.  Paralaophonte pacificavicinum sp. nov., female. (A) Anal somite and caudal rami (seta I arrowed), dorsal; (B) P5. Scale bars: A, B, 50 µm. P2 ( Figure 34B). Praecoxa with transverse row of outer spinules. Coxa with spinular rows as figured. Basis with spinules at base of outer spine-like element. Exopod three-segmented; EXP1 without, EXP2 with inner seta; EXP3 with three outer spines, two apical and one inner element. Endopod two-segmented, reaching insertion site of inner seta of EXP2; ENP1 without armature; ENP2 with two inner (proximalmost smaller) and two apical setae. P3 ( Figure 35A). Praecoxa as in P2. Coxa and basis as in P2, except for slen- der and bare basal seta. Exopod three-segmented; EXP1 without, EXP2 with inner seta; EXP3 with three outer spines, two apical and two inner elements. Endopod twosegmented, reaching insertion site of inner seta of EXP2; ENP1 without armature; ENP2 with three inner setae, two apical and one outer element.  Figure 33.  Paralaophonte pacificavicinum sp. nov., female. (A) Antennule; (B) antenna; (C) mandible; (D) maxillule; (E) maxilla; (F) maxilliped. Scale bars: A–F, 50 µm. P4 ( Figure 35B). Praecoxa, coxa, basis and exopod as in P3 (though P4 EXP3 somewhat different in general shape). Endopod two-segmented, reaching slightly beyond EXP1; ENP1 without armature; ENP2 with one inner seta, two apical and one outer element. P5 ( Figure 32B) large, with separate rami. Baseoendopodal lobe well developed, not reaching to middle of EXP, with spinules as shown; with four setae; outer basal seta arising from short setophore. Exopod covered with spinules, with five setae; two outermost bare elements of equal length. P6 ( Figure 31B) represented by one seta. Armature formula of P1–P5 as in Table 3.   Male.Habitus (not shown) as in female except for separate second and third urosomites ventrally, and for longer spinules on third, fourth and fifth urosomites ventrally along posterior margin ( Figure 36A). Urosome more slender than in female. Total  Figure 34.  Paralaophonte pacificavicinum sp. nov., female. (A) P1; (B) P2. Scale bars: A, B, 50 µm.  Figure 35.  Paralaophonte pacificavicinum sp. nov., female. (A) P3; (B) P4. Scale bars: A, B, 50 µm.  Table 3. Armature formula of swimming legs of Paralaophonte pacificavicinum sp. nov.    EXP ENP  P1 I-0;I-0;II,2,0 0-0;0,I1,0  P2 I-0;I-1;III,I1,1 0-0;0,2,2  Female P3 I-0;I-1;III,I1,2 0-0;1,2,3  Male P3 I-0;I-I;II,II,1II 0-0;apophysis-0;0,2,2  P4 I-0;I-1;III,I1,2 0-0;1,2,1  Female P5 5 4 + 1 (basal)  Male P5 5 1 + 1 (basal) body length ranging from 350 to 420 µm measured from tip of rostrum to posterior margin of caudal rami (mean = 378 µm; n= 4). Antennule ( Figure 37A) eight-segmented, subchirocer; second segment with conical outer process; sixth segment with two acute projections. Armature formula difficult to define: I-(1); II-(9);III-(6);IV-(0);V-(11 + ae);VI-(0);VII-(1);VIII-(8 + acrothek). Acrothek consisting of two setae and one aesthetasc fused basally. Antenna, mandible, maxillule, maxilla, maxilliped and P1 (not shown) as in female. P2 EXP ( Figure 36B) as in female. P2 ENP ( Figure 36B) dimorphic, twosegmented, distalmost inner seta modified as depicted. P3 ( Figure 36C) dimorphic. Exopod three-segmented; segments more strongly developed than in female; EXP1 without, EXP2 with one, EXP3 with two inner elements; setae and spines very strong and without ornamentation except for outer spine on EXP1; relative length of spines on EXP3 as depicted. Endopod three-segmented; ENP1 without armature; ENP2 with outer apophysis reaching beyond ENP3, the latter with two inner and two apical setae. P4 (not shown) as in female, except for comparatively longer outer spines, longer outer apical element of EXP3 and shorter inner seta of EXP2. Left and right P5 fused ( Figure 37B); baseoendopodal lobe with one seta plus outer seta of basis; exopod with five setae as figured. P6 ( Figure 37C) represented by two plates bearing one outer slender seta and one inner strong spine-like element.  Remarks The descriptions of  P. pacificaemulator sp. nov.and  P. pacificavicinum sp. nov.match  P. pacifica.In fact, the former two species seem to be closely related to the latter, agree well in almost all characters with Lang’s (1965)description of  P. pacifica, and are hence hypothesized to co-occur sympatrically in north-western Mexico.  Paralaophonte pacificaemulator sp. novand  P. pacificacan be distinguished from each other by the shape of the female P5 EXP (comparatively more elongate in  P. pacifica; broader in  P. pacificaemulator sp. nov.), relative length of two inner elements of the female P5 BENP (reaching well beyond baseoendopodal lobe in  P. pacifica, noticeably shorter in  P. pacificaemulatorsp nov.), and relative length of the female P3 ENP (not reaching the insertion level of the inner seta of P3 EXP 2 in  P. pacifica, reaching slightly beyond the insertion site of the same seta in  P. pacificaemulator sp. nov) and female P4 ENP (reaching the insertion site of the inner seta of P4 EXP 2 in  P. pacifica, barely reaching the tip of P4 EXP 1 in  P. pacificaemulator sp. nov.), relative length of the spines on the male P3 EXP3 (distalmost outer spine stronger than apical spine in  P. pacifica, both spines equal in  P. pacificaemulator sp. nov.), relative length of the baseoendopodal seta of male P5 (shorter than exopod in  P. pacifica, noticeably longer in  P. pacificaemulator sp. nov.), and relative length of the outer seta of male P6 (longer than inner element in  P. pacifica, noticeably shorter in  P. pacificaemulator sp. nov.). Contrary to  P. pacificaemulator sp. nov., the female P5 of  P. pacificavicinum sp. novand  P. pacificaas shown in Lang’s (1965)description are identical, with only very small differences in relative length of the baseoendopodal and exopodal setae. Also, some differences were observed regarding the relative length of the setae of the mandibular palp, being comparatively shorter in  P. pacificavicinum sp. nov.  Paralaophonte pacificavicinum sp. nov.can be distinguished from  P. pacificaby the relative length of the female P3 ENP (not reaching the insertion level of the inner seta of P3 EXP 2 in  P. pacifica, reaching slightly beyond the insertion site of the same seta in  P. pacificavicinum sp. nov), relative length of the spines on the male P3 EXP3 (distalmost outer spine as long as the outer apical spine in  P. pacifica, noticeably shorter in  P. pacificavicinum sp. nov.), relative length of the baseoendopodal seta of male P5 (shorter than exopod in  P. pacifica, noticeably longer in  P. pacificavicinum sp. nov.), and relative length of the outer seta of male P6 (longer than inner element in  P. pacifica, but slightly shorter in  P. pacificavicinum sp. nov.).  Figure 36.  Paralaophonte pacificavicinum sp. nov., male. (A) Urosome, ventral; (B) P2; (C) P3. Scale bars: A, 100 µm; B, C, 50 µm.  Figure 37.  Paralaophonte pacificavicinum sp. nov., male. (A) Antennule; (B) P5; (C) P6. Scale bars: A–C, 50 µm.   Paralaophonte pacificaemulator sp. nov.and  P. pacificavicinum sp. nov.can be distinguished from each other by the shape of the female P5 EXP (comparatively broader in  P. pacificaemulator sp. nov.), and the relative length of its two outermost setae of the female P5 EXP (equal in  P. pacificavicinum sp. nov., outermost element noticeably shorter in  P. pacificaemulator sp. nov.), relative length of the spines of the male P3 EXP3 (distalmost outer spine as long as outer apical spine in  P. pacificaemulator sp. nov., noticeably shorter in  P. pacificavicinum sp. nov.), and relative length of the baseoendopodal seta of the male P5 (longer than inner most element of P5 EXP in  P. pacificaemulator sp. nov., nearly as long as inner most element of P5 EXP in  P. pacificavicinum sp. nov.). Also, the two acute projections on the sixth segment of the male antennule are comparatively longer in  P. pacificaemulator sp. nov.than in  P. pacificavicinum sp. nov. Dissected 38 365 1 1 paratype CIII Mexico 24.583334 Ensenada del Pabellon 1250 -107.75 38 365 1 1 Sinaloa paratype 1991-05-02 Mexico 2 23.185 Urias System 21 -106.41833 Morales-Serna 39 366 1 Sinaloa [211,1089,1311,1339] Mexico 23.185 Urias System 21 -106.41833 40 367 1 Sinaloa holotype Mexico 19.315332 Ensenada del Pabellon 1 -91.11653 40 367 1 Sinaloa