Paralaophonte pacificavicinum, Gómez & Morales-Serna, 2013

Gómez, S. & Morales-Serna, F. N., 2013, On a small collection of Laophontidae T. Scott (Copepoda: Harpacticoida) from Mexico. I. New species and new records of Laophonte Philippi and Paralaophonte Lang, Journal of Natural History 47 (5 - 12), pp. 329-380: 363-378

publication ID

http://doi.org/ 10.1080/00222933.2012.757657

persistent identifier

http://treatment.plazi.org/id/2C4C87C9-DF24-7D26-FE28-203EFE32FC47

treatment provided by

Felipe

scientific name

Paralaophonte pacificavicinum
status

sp. nov.

Paralaophonte pacificavicinum   sp. nov.

( Figures 30–37 View Figure 30 View Figure 31 View Figure 32 View Figure 33 View Figure 34 View Figure 35 View Figure 36 View Figure 37 )

Material examined

One female holotype (EMUCOP-021205-04) and one male allotype (EMUCOP- 021205-05) preserved in alcohol. Paratypes preserved in alcohol: two females and

two males (EMUCOP-020591-05), one female and four males (EMUCOP-021205-06), one female and one male (EMUCOP-080205-20), one adult male (EMUCOP-080205- 21), four females (EMUCOP-080205-22), two males (EMUCOP-090301-36), three females and 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 Pabellón lagoon (Sinaloa State, north-western Mexico) (24 ◦ 19 ′ – 24 ◦ 35 ′ N, 107 ◦ 28 ′ – 107 ◦ 45 ′ W), stn. 3 (see Gómez-Noguera and Hendrickx GoogleMaps  

1997, for more information regarding nitrogen and carbon content and sediment type), brackish, less than 2 m depth, 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 GoogleMaps  

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 a content and sediment type), brackish, less than 2 m depth, 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).

Type locality

Urías System (Sinaloa State, north-west Mexico) (23 ◦ 11 ′ 06 ′′ N, 106 ◦ 25 ′ 06 ′′ W) GoogleMaps   .

Other localities

Ensenada del Pabellón lagoon (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) GoogleMaps   .

Etymology

The specific epithet pacificavicinum   ( pacifica   after P. pacifica   ; Latin, vicinum, neighbour) makes reference to the strong resemblance to P. pacifica   .

Description

Female. Habitus fusiform ( Figure 30A, B View Figure 30 ). 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 View Figure 30 ), 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 View Figure 30 , 31A, B View Figure 31 ) 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 View Figure 31 , 32A View Figure 32 ) 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 View Figure 31 , 32A View Figure 32 ) 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 View Figure 31 ); with seven elements; seta I very small (arrowed in Figure 32A View Figure 32 ), 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 View Figure 33 ) 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 View Figure 33 ). 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 View Figure 33 ). 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 View Figure 33 ). 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.

Maxilla ( Figure 33E View Figure 33 ). 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 View Figure 33 ). 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 View Figure 34 ). 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.

P2 ( Figure 34B View Figure 34 ). 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 View Figure 35 ). 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.

P4 ( Figure 35B View Figure 35 ). 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 View Figure 32 ) 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 View Figure 31 ) 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 View Figure 36 ). Urosome more slender than in female. Total

sp. nov.

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 View Figure 37 ) 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 View Figure 36 ) as in female. P2 ENP ( Figure 36B View Figure 36 ) dimorphic, twosegmented, distalmost inner seta modified as depicted.

P3 ( Figure 36C View Figure 36 ) 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 View Figure 37 ); baseoendopodal lobe with one seta plus outer seta of basis; exopod with five setae as figured.

P6 ( Figure 37C View Figure 37 ) 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. nov and P. pacifica   can 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. pacificaemulator   sp 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. nov and P. pacifica   as 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. pacifica   by 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.).

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.