Phyllopodopsyllus parastigmosus, Gómez & Morales-Serna, 2015

Gómez, Samuel & Morales-Serna, Francisco Neptali, 2015, On a small collection of Tetragonicipitidae Lang, 1944 (Copepoda: Harpacticoida) from Mexico: new records and new species, Journal of Natural History 49 (45), pp. 2827-2868 : 2839-2850

publication ID	https://doi.org/ 10.1080/00222933.2015.1038329
DOI	https://doi.org/10.5281/zenodo.4330209
persistent identifier	https://treatment.plazi.org/id/D112879B-0630-EE04-D8BF-FE1C5754F4A0
treatment provided by	Carolina
scientific name	Phyllopodopsyllus parastigmosus
status	sp. nov.

Treatment

Phyllopodopsyllus parastigmosus View in CoL sp. nov.

( Figures 8A, B View Figure 8 , 9A, B View Figure 9 , 10A–D View Figure 10 , 11A, B View Figure 11 , 12A, B View Figure 12 , 13A–D View Figure 13 , 14 View Figure 14 , 15A–D View Figure 15 )

Type locality

Ensenada del Pabellón , Sinaloa State; 24.3167 –24.5833 ° N GoogleMaps , 107.4667– 107.75° W.

Type material

Female holotype, dissected (EMUCOP-010192–01); male allotype, dissected (EMUCOP- 010192 –02).

Etymology

The specific name alludes to the strong resemblance to P. stigmosus Wells and Rao, 1987 .

Description

Female. Habitus (not shown) fusiform; tapering from posterior margin of cephalothorax to anal somite. Second and third urosomites fused forming genital doublesomite, with remains of former division ventrally, completely fused dorsally ( Figure 8A, B View Figure 8 ). Genital double-somite and following urosomite with ventral and dorsal pores and sensilla and spinules as figured ( Figure 8A, B View Figure 8 ). Fifth urosomite without sensilla, with two ventral pores. Anal somite ( Figure 8A, B View Figure 8 ) slightly shorter than preceding somite; dorsally ( Figure 8A View Figure 8 ) with two pores and two sensilla, ventrally ( Figure 8B View Figure 8 ) with two pores close to medial cleft; with minute spinules along posterior margin ventrally; with rounded anal operculum ornamented with spinules along posterior margin ( Figure 8A View Figure 8 ). Caudal rami as figured, elongate, about 3.7 times as long as broad; with six setae as follows: seta II in proximal third ventrally; seta III smaller than seta II, situated laterally on distal fourth of ramus; seta IV as long as seta III, fused to seta V; seta VI inserted on inner distal corner of caudal armus, half as long as seta IV; dorsal seta VII long, biarticulated.

Antennule ( Figure 9A View Figure 9 ). Eight-segmented; first segment elongate, about 2.3 times as long as broad; second segment slightly longer than broad, with strong acute process; armature formula as follows: 1(1); 2(9); 3(8); 4(3+(1+ae)); 5(2); 6(3); 7(4); 8(5+(1+ae)).

Antenna ( Figure 9B View Figure 9 ). With basis; the latter about twice as long as broad, with inner longitudinal row of minute spinules; exopod one-segmented, with three elements (apicalmost fused to exopod). First endopodal segment without armature; second endopodal segment with medial and distal hyaline frills; with one slender seta and two spines laterally, and with five elements distally as shown.

Mandible ( Figure 10A View Figure 10 ). Gnathobase with three bicuspidate teeth, some spinules and one lateral pinnate seta. Coxa-basis with some medial spinules as shown, with three setae. Exopod one-segmented, with two lateral and seven distal setae. Endopod onesegmented, with one lateral and three distal setae.

Maxillule ( Figure 10B View Figure 10 ). Arthrite of praecoxa with two surface setae, one lateral pinnate seta and eight distal spines. Coxa with epipodal plumose seta and with two pinnate and three slender apical elements. Basis with eight setae. Exopod onesegmented, large, with one lateral strong seta, two subdistal and one apical element. Endopod one-segmented, small, with three setae.

Maxilla ( Figure 10D View Figure 10 ). Syncoxa with four endites; proximal endite with two, second endite with one, third endite with three, distal endite with three setae. Basis with

strong claw and two slender setae. Endopod two-segmented; first segment with three, second segment with four setae.

Maxilliped ( Figure 10C View Figure 10 ). Syncoxa with spinules as figured and with three inner setae. Basis with longitudinal row of inner spinules and with one inner seta; endopodal segment elongate, with long claw and one seta.

P1 ( Figure 11A View Figure 11 ). Coxa large, with spinules as figured. Basis with outer slender seta and strong bipinnate inner spine; with sparse spinules at base of inner element. Exopod three-segmented; first and second segments with outer spine; third segment with four elements. Endopod two-segmented; first segment elongate, about 5.7 times

as long as broad, with one inner element on distal third; second segment small, about twice as long as broad, with two apical elements.

P2 ( Figure 11B View Figure 11 ). Coxa large, with spinules as shown. Basis with sparse posterior spinules, with outer long seta. Exopod three-segmented; first segment with inner seta, second segment without inner seta; third segment with two outer spines, two apical and one inner element. Endopod two-segmented, reaching about proximal fifth of EXP3; first segment unarmed; second segment with three elements.

P3 ( Figure 12A View Figure 12 ). Coxa large, with spinules as shown. Basis with outer long seta. Exopod three-segmented; first segment with, second segment without inner seta; third segment with two outer spines, two apical and two inner elements. Endopod twosegmented, reaching about the distal fourth of EXP2; first segment with one inner element; second segment with three elements.

P4 ( Figure 12B View Figure 12 ). Coxa large, with spinules as shown. Basis with outer long seta. Exopod three-segmented; first and second segments with inner seta; third segment with two outer small spines, two apical and three inner elements as shown. Endopod two-segmented, reaching tip of EXP1; first segment small, with one inner element; second segment elongate, with three setae.

P5 ( Figure 13D View Figure 13 ). Large, foliose, forming brood pouch; with 11 setae.

P6 ( Figure 8B View Figure 8 ). Each leg represented by small lobe bearing one long outer and one minute inner seta.

Male. Habitus (not shown) as in female. Surface ornamentation of urosomites as in female, except for continuous row of minute spinules along posterior margin of third and fourth urosomites ventrally. Anal somite and anal operculum ( Figure 13A View Figure 13 ) as in female. Caudal rami more slender than in female, elongate, about 5.7 times as long as wide, with six setae ( Figure 13A–C View Figure 13 ); all setae as in female, except for seta VII situated more distally in male.

Antennule ( Figure 14 View Figure 14 ). Seven-segmented, subchirocer; first segment elongate, about 1.8 times as long as wide; second segment nearly as long as wide, with strong acute process. Armature formula difficult to define, most probably as follows: 1(1); 2(9); 3(6); 4(9+(1+ae)); 5(0); 6(1); 7(10+(1+ae)?).

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

P1 (not shown). As in female.

P2 ( Figure 15A View Figure 15 ). Coxa, basis and exopod as in female. Endopod two-segmented; first segment unarmed; second segment sexually dimorphic, with one inner apophysis and one seta distally.

P3EXP (not shown). As in female. Endopod ( Figure 15D View Figure 15 ) as in female except for comparatively longer seta of ENP1 and smaller medial seta of ENP2.

P4 ( Figure 15B View Figure 15 ). Coxa and basis as in female. Exopod as in female except for outer distal process at base of outer spine of male EXP2 (triangular arrow in Figure 15B View Figure 15 ) and for six instead of seven elements in EXP3. Endopod as in female except for two instead of three setae on ENP2.

P5 ( Figure 15C View Figure 15 ). Baseoendopods of both legs fused, with outer basal seta and with three elements on inner endopodal lobe. Exopod with five setae as shown; with acute distal process.

P6 ( Figure 13A View Figure 13 ). Represented by transverse plate bearing both P6; each leg represented by well-developed lobe bearing three elements.

Remarks

Phyllopodopsyllus tenuis was originally described inhabiting fine to medium sandy bottoms with algae and high amounts of detritus from Seaward Bay (Mayabandar, North Andaman). The Mexican specimen fits well the description by Wells and Rao (1987), especially in the shape and length:width ratio of the caudal rami and shape of caudal seta V ( Figure 1A–C View Figure 1 ), number of segments and shape of the female ( Figure 2A View Figure 2 ) and male ( Figure 6A View Figure 6 ) antennule, shape of the female ( Figure 4F View Figure 4 ) and male ( Figure 7D View Figure 7 ) P5, general shape of female ( Figure 3A–C View Figure 3 ) and male ( Figure 6C View Figure 6 ) P1, female P2 ( Figure 3D View Figure 3 ), female P3 ( Figure 4B–E View Figure 4 ) and male P3ENP ( Figure 7C View Figure 7 ), and female ( Figure 4A View Figure 4 ) and male ( Figure 7B View Figure 7 ) P4ENP. Some slight differences were observed regarding the number of setae on the endopodal segment of the maxilliped and regarding the relative length of some setae of the female and male P5. Also, the apical innermost seta of P2EXP3 and the apical seta of P4ENP2 of the Mexican female specimen might have fallen off during sample processing. The innermost minute seta of the female P3ENP2, and of the male P3ENP2 and P4ENP2 as shown by Wells and Rao (1987, p. 349, fig. 125 b, e, f) are in fact acute projections of the supporting segment in the Mexican material. The Mexican material presented herein is proposed to be attributed to P. tenuis until more specimens from the Gulf of Mexico are available for further inspection.

Kunz (1984) suggested nine species-groups (bradyi-, furciger-, aegypticus-, borutzkyi-, pauli-, opistoceratus-, mossmani-, xenus - and longipalpatus -group) for the genus Phyllopodopsyllus based on the number of segments of the female antennule, presence/absence of an unguiform projection on the second antennular segment, and structure and chaetotaxy of the female swimming legs. Fiers (1995) questioned the naturalness of these groups but recognized it as useful as an identification tool, and commented on the difficulties of performing sound phylogenetic interpretations with the current knowledge of the expression of sexual dimorphism, among other characters.

Currently, Kunz’ s (1984) furciger -group, which he defined by the presence of (1) a female eight-segmented, antennule, (2) five and six setae/spines on the P2EXP3 and P3EXP3, (3) one inner seta on the P4EXP2, and (4) a two-segmented P4ENP, is composed by P. furciger Sars, 1907 , P. minutus Lang, 1948 , P. bermudae Lang, 1948 , P. parafurciger parafurciger Geddes, 1968 , P. parafurciger carolinensis Coull, 1971 , P. chavei Coull, 1970 , P. langi Kunz, 1975 , P. curtus Marcus, 1976 , P. stigmosus Wells and Rao, 1987 , P. galapagoensis Mielke, 1989 and P. yucatanensis Fiers, 1995 . Following Fiers (1995), P. yucatanensis , P. parafurciger parafurciger and P. parafurciger carolinensis seem to be related, based on the presence of an additional sharp process on the anterior distal corner of the second antennular segment, which as noted by Fiers (1995) is also present in other speciesgroups of Phyllopodopsyllus .

The Mexican material differs from the other species of the group in the armature formula of P3ENP1, P4EXP3 and P4ENP2, (compared with P. minutus ), shape of the caudal seta V, relative length of P1ENP1, and armature formula of P3ENP1 and P4EXP3 (compared with P. bermudae ), shape of the female caudal ramus, and armature formula of the male P4ENP2 (compared with P. furciger and P. galapagoensis ), armature formula of P2ENP1, shape of the female caudal ramus, relative length of the male P4ENP, shape of the male P5, armature formula of the male P2ENP2 (compared with P. galapagoensis ), shape of the caudal ramus, armature formula of the female P4EXP3, P4ENP2 and P4EXP3, shape and chaetotaxy of the male P3EXP, P3ENP and P4EXP3, and shape of the male P5 (compared with P. langi ), shape of the female caudal ramus and caudal seta V, armature formula of the female P2ENP1, P4EXP3 and shape of the male P5 (compared with P. chavei ), so reinforcing Fiers (1995) doubts about the naturalness of Kunz’ s (1984) groupings.

Marcus (1976) described P. curtus from the Libyan coast of the Mediterranean, and a decade later, Wells and Rao (1987) described P. stigmosus from several places in the Andaman and Nicobar Islands. Despite the marked differences observed by Marcus (1976, p. 123, Table 1), he hypothesized a closer relationship between P. curtus , P. bermudae and P. longicaudatus , and Wells and Rao (1987) could not define any relationship between P. stigmosus and other species of the genus known at that time. Phyllopodopsyllus parastigmosus sp. nov. seems to be more closely related to P. curtus and to P. stigmosus than to any other species. In fact, P. parastigmosus sp. nov. fits Wells and Rao’ s (1987) description of P. stigmosus and Marcus’ s (1976) description of P. curtus in almost every character, especially in the combination of the following: general shape of the female caudal rami ( Figure 8A, B View Figure 8 ), expression of sexual dimorphism in the male caudal rami (more slender in the male) ( Figure 13A– C View Figure 13 ) and in the armature formula of the P4EXP3 [with seven elements in the female, but only six in the male, though not conclusive for P. curtus in Marcus (1976) ], shape and general structure of the female antennule ( Figure 9A View Figure 9 ) (with the first segment as long as the succeeding five segments combined), shape and armature of the female P1–P4 ( Figures 11A, B View Figure 11 , 12A, B View Figure 12 , 15A, B, D View Figure 15 ), and general shape of the female ( Figure 13D View Figure 13 ) and male ( Figure 15C View Figure 15 ) P5, and general sexual dimorphism in swimming legs. Phyllopodopsyllus parastigmosus sp. nov., P. stigmosus and P. curtus can be separated by the relative length of the P1ENP1 (P1ENP1 1.2 times as long as P1EXP in P. paratigmosus sp. nov. and P. stigmosus , but 1.7 times in P. curtus ), by the relative length of the P2ENP (shorter than P2EXP1 and EXP2 combined in P. stigmosus , but P2ENP reaching beyond P2EXP 2 in P. parastigmosus sp. nov. and P. curtus ); by the P3ENP (comparatively more elongated, reaching the distal third of P3EXP 2 in the new species and in P. curtus , but P3ENP2 comparatively shorter and reaching proximal third of P3EXP 2 in P. stigmosus ; by the number of setae on the female P5 (11 setae in the new species, but 10 setae in P. stigmosus and P. curtus ), and by the relative length of the setae of the male P5 (more similar between P. parastigmosus sp. nov. and P. curtus ) and P6 (more similar between P. curtus and P. stigmosus ).