Typhlamphiascus medici, Gómez & Corgosinho & Rivera-Sánchez, 2021

Gómez, Samuel, Corgosinho, Paulo Henrique Costa & Rivera-Sánchez, Karen I., 2021, Proposal of new genera and species of the subfamily Diosaccinae (Copepoda: Harpacticoida: Miraciidae), European Journal of Taxonomy 759 (1), pp. 1-62 : 12-24

Typhlamphiascus medici sp. nov.

urn:lsid:zoobank.org:act:67A13A9C-4D1E-4F86-82F2-CEE5407BCD26

Figs 1–10

Etymology

The specific epithet from the Latin ‘medicī’, ‘doctor’, ‘physician’, is dedicated in honour and to the memory of all physicians and health personnel for their self-sacrifice during the fight against the COVID-19 pandemic. It is in the genitive singular, gender masculine.

Material examined

Holotype MEXICO • ♀ (preserved in alcohol); Sinaloa State, Mazatlán, Urías coastal system, stn 2 (see also Gómez 2020a: 43, fig. 1); 23.1587° N, 106.3326° W; 1.8 m depth; 18 Jan. 2019; S. Gómez leg.; organic carbon content 3.99%, organic matter content 6.86%, sand 80.42%, clay 8.29%, silt 11.28%; ICML- EMUCOP-180119-40.

Allotype MEXICO • ♂ (preserved in alcohol); same collection data as for holotype; ICML-EMUCOP-180119-43 . Other paratypes

MEXICO • 3 ♀♀ (preserved in alcohol); same collection data as for holotype; ICML-EMUCOP-180119- 103 • 2 ♀♀, 2 ♂♂ (preserved in alcohol); same collection data as for holotype; ICML-EMUCOP-180119- 46 • 1 ♀ (dissected); same collection data as for holotype; ICML-EMUCOP-180119-41 • 1 ♀ (dissected); same collection data as for holotype; ICML-EMUCOP-180119-42 • 1 ♂ (dissected); same collection data as for holotype; ICML-EMUCOP-180119-44 • 1 ♂ (P1 and P2 dissected, rest intact and preserved in alcohol); same collection data as for holotype; ICML-EMUCOP-180119-45 .

Other material

MEXICO • 8 CV, 4 CIV, 1 CII (preserved in alcohol); same collection data as for holotype; ICML- EMUCOP-180119-47 • 1 ♀, 2 ♂♂, 2 CV (preserved in alcohol); Sinaloa State, Mazatlán, Urías coastal system, stn 4 (see also Gómez 2020a: 43, fig. 1); 23.1840° N, 106.3579° W; 0.7 m depth; 18 Jan. 2019; S. Gómez leg.; organic carbon content 1.13%, organic matter content 1.94%, sand 82.44%, clay 8.27%, silt 9.29%; ICML-EMUCOP-180119-48 • 1 CV, 1 CIV, 1 CI (preserved in alcohol); Sinaloa State, Mazatlán, Urías coastal system, stn 5 (see also Gómez 2020a: 43, fig. 1); 23.2056° N, 106.3715° W; 0.6 m depth; 18 Jan. 2019; S. Gómez leg.; organic carbon content 0.99%, organic matter content 1.71%, sand 78.61%, clay 6.72%, silt 14.67%; ICML-EMUCOP-180119-49 • 1 ♂, 1 CIII (preserved in alcohol); same collection data as for preceding; ICML-EMUCOP-180119-50 • 1 ♀, 2 CIV, 1 CII (preserved in alcohol); same collection data as for preceding; ICML-EMUCOP-180119-51 • 1 CV, 1 CIII, 2 CII (preserved in alcohol); Sinaloa State, Mazatlán, Urías coastal system, stn 6 (see also Gómez 2020a: 43, fig. 1); 23.2123° N, 106.3780° W; 1.4 m depth; 18 Jan. 2019; S. Gómez leg.; organic carbon content 1.65%, organic matter content 2.84%, sand 61.44%, clay 14.57%, silt 23.99%; ICML- EMUCOP-180119-52 • 1 ♂, 1 CV, 1 CIV (preserved in alcohol); same collection data as for preceding; ICML-EMUCOP-180119-53 • 1 ♂ (preserved in alcohol); same collection data as for preceding; ICML- EMUCOP-180119-54 ) • 1 ♀, 1 CIV (preserved in alcohol); Sinaloa State, Mazatlán, Urías coastal system, stn 10 (see also Gómez 2020a: 43, fig. 1); 23.1815° N, 106.4214° W; 6.0 m depth; 18 Jan. 2019; S. Gómez leg.; organic carbon content 1.2%, organic matter content 2.07%, sand 69.12%, clay 7.91%, silt 22.97%; ICML-EMUCOP-180119-55 • 3 CIV (preserved in alcohol); same collection data as for preceding; ICML-EMUCOP-180119-56 .

Description

Female

GENERAL. Total body length measured from tip of rostrum to posterior margin of caudal rami ranging from 705 to 850 µm (mean 762 µm; n = 5; total body length of holotype 850 µm); habitus fusiform, widest at posterior end of cephalothorax in dorsal view, tapering posteriad ( Fig. 1A ).

PROSOME ( Figs 1A–B , 2A ). 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 finely serrated, striated, of fourth pedigerous somite visibly narrower, finely serrated, without striations.

UROSOME ( Figs 1A–D , 2A ). Consisting of fifth pedigerous somite (first urosomite), genital doublesomite (genital – second urosomite – and third urosomites fused), two free urosomites, anal somite and caudal rami; urosomites without expansions. First urosomite narrower than preceding somites in dorsal view ( Fig. 1A ), without spinular ornamentation, with posterior sensilla as depicted, with one lateral pore on each side ( Fig. 1C ), posterior frill as in preceding somite dorsally and laterally ( Fig. 1A, C ). Genital double-somite ( Figs 1A, C , 2A ) rectangular, slightly longer than wide, with sensilla and minute surface spinules dorsolaterally as shown; anterior and posterior halves (second – genital – urosomite and third urosomite, respectively) distinct dorsally and laterally ( Fig. 1A, C ), completely fused ventrally ( Fig. 2A ); dorsolateral posterior margin of anterior half serrated and with two large spinules on each side ( Fig. 1A, C ); posterior half of genital double-somite with dorsal ( Fig. 1A ) and lateral ( Figs 1C , 2A ) large posterior spinules, posterior hyaline frill deeply incised and striated, the latter continuous dorsolaterally ( Fig. 1A, C ) and interrupted ventrally ( Fig. 2A ); P6 at anterior third of genital somite (anterior half of genital double-somite) and with genital field as shown ( Fig. 2A ). Fourth urosomite largely as in posterior half of genital double-somite, but with additional paired lateroventral pores and posterior medial transverse spinular row ( Figs 1A, C , 2A ). Fifth urosomite without sensilla, with one lateral row of small spinules ( Fig. 1C ) and with paired lateroventral pores ( Figs 1C , 2A ), with short medial row of large spinules ventrally ( Fig. 2A ), with continuous deeply incised posterior hyaline frill, the latter with medial part slightly crescentic dorsally ( Fig. 1A ). Anal somite slightly wider than long in dorsal view ( Fig. 1A–B ), without anal operculum, cleft medially dorsally ( Fig. 1A–B ) and ventrally ( Fig. 2A ), with two posterior sensilla dorsally ( Fig. 1A–D ), with lateral and ventral pores as shown ( Figs 1C–D , 2A ), and with small spinules close to joint with caudal rami. Caudal rami well-developed ( Figs 1A–D , 2A ), about 1.7 times as long as wide and with straight outer and slightly convex inner margin ( Fig. 1A–B ), with pores as shown; with seven setae ( Fig. 1B ) 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; dorsal seta VII issuing subdistally, close to inner margin, triarticulated.

ROSTRUM ( Figs 1A, C , 3A–B ). Not fused to cephalothorax, triangular, pointed, with one sensilla arising at distal third on each side, reaching distal margin of second antennulary segment.

ANTENNULE ( Fig. 3A–B ). Eight-segmented; all segments smooth; first and second segments with tube pore (arrowed in Fig. 3A ); all setae smooth except for two and three biarticulated setulose setae on seventh and eight segments, respectively; outer subdistal seta of eighth segment biarticulated basally, neighbouring seta swollen basally. Armature formula: 1(1); 2(11); 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–D ). 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, without abexopodal seta. Exopod three-segmented; first segment longer than second and third segments combined, second segment smallest; first and second segments unornamented, the former with one, the latter without seta; third segment with subapical row of spinules, armed with three setae, of which one bare, the other two bipinnate. Free endopodal segment with proximal and subdistal inner strong spinules as shown, and with two outer frills; armed with two lateral inner flagellate spines and two slender setae (the latter set close to each other), one inner apical flagellate spine, three single geniculate setae, one slender bipinnate 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, subdistally with two small slender setae and two spinules medially, and with one strongly spinulose element. Basis massive, with spinules as depicted, with three inner setae. Exopod twosegmented; first segment longer than second, the former with one lateral and one distal seta, the latter with one apical element. Endopod one-segmented, visibly larger that exopod; with two lateral and six distal setae.

MAXILLULE ( Fig. 4B ). With arthrite ornamented with some slender spinules and armed with two surface setae, seven distal spines as shown, one spinulose element and one recurved stiff pinnate seta. Coxal endite with three setae. Basis with spinular row as depicted and armed with two lateral, one subdistal and three distal elements, one of which visibly stronger. Rami one-segmented, exopod with two, endopod with four elements – two distal, one inner subdistal and one inner medial seta.

MAXILLA ( Fig. 5A ). With large syncoxa ornamented with small outer spinules; with three endites; proximal endite smallest, with three setae; middle and distal endites nearly subequal in length, the former with two, the latter with three setae. Basis drawn out into strong claw with minute pinnae, additionally

with strong spine bearing one long spinule and two slender setae – one anterior, one posterior. Endopod two-segmented; first segment with two, second segment with one lateral and four distal setae.

MAXILLIPED ( Fig. 5B ). Subchelate. Praecoxa small, trapezoidal, ornamented with slender outer spinules. Coxa trapezoidal, with proximal, medial and subdistal spinules as shown; with two inner small setae issuing at distal fourth and two long apical setae. Basis longer than coxa, oval, with outer slender longitudinal spinules, and 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 small distal – and apical claw.

P1 ( Fig. 6A–B ). With broad unornamented intercoxal sclerite ( Fig. 6B ). Coxa massive, with several spinular rows as shown. Basis with inner and outer spinulose spines; with slender long inner spinules proximally and close to insertion of inner spine, and with shorter but stronger spinules at base of inner and outer seta, and distally on medial distal rounded protrusion. Exopod three-segmented, arising at a lower level than that of the endopod and reaching slightly beyond ENP1; ENP: EXP length ratio 1.5; exopodal segments subequal in length, with strong outer spinules as shown; first segment without, second segment with one inner seta with comb tip; third segment with five elements. Endopod three-segmented, arising from pedestal; ENP1 about four times as long as wide, as long as second and third segments combined, with outer and inner longitudinal rows of slender spinules, with one inner stiff, long, strongly pectinate seta; second and third segments ornamented with strong outer spinules as shown, the former shorter, nearly as long as wide and half as long as the latter, with one inner, slender, short seta; third segment elongate with one inner distal slender seta, one apical long element and one outer distal spine.

P2 ( Fig. 6B ). Narrow intercoxal sclerite (not shown) with acute distal projection on each side, largely as in P3. Praecoxa (not shown) as in P3. Coxa with three anterior rows of spinules – one proximal and two medial transverse – and with posterior small spinules close to proximal outer margin. Basis with long slender spinules proximally close to inner margin, with small spinules between rami, and with comparatively larger spinules at base of exopod and at base of outer pinnate spine. Rami threesegmented, endopod and exopod subequal in absolute length. Exopod three-segmented, arising at a lower level than that of the endopod, not reaching tip of ENP; exopodal segments with strong outer spinules as shown; EXP1 and EXP2 with outer distal acute projection, on EXP1 shorter, both segments with coarse inner distal hyaline frill and inner seta with comb tip, on EXP1 visibly shorter; EXP3 with six elements – three outer spines, two apical elements and one inner seta with comb tip. Endopod three-segmented, arising from pedestal; endopodal segments with strong outer spinules as shown; ENP1 shortest, as long as wide, with small distal spinules close to small inner projection, without outer distal projection nor inner hyaline frill, with one short inner seta; ENP2 elongate, 1.7 times as long as wide and 0.6 times as long as ENP3, with strong outer spinules and with small spinules at base of outer distal acute projection, with coarse inner distal frill, with two inner setae of which proximal one short; ENP3 longest, elongate, 4.8 times as long as wide, with medial outer pore, with four elements (one inner and two apical setae, and one outer spine), with acute projection between outer spine and inner apical seta.

P3 ( Fig. 7A ). Narrow intercoxal sclerite with acute distal projection on each side. Praecoxa small, with transverse distal row of slender spinules close to outer margin. Coxa and basis as in P2 except for outer setiform element of basis on P3. Rami three-segmented, endopod and exopod subequal in absolute length. Exopod largely as in P2 except for additional posterior pore on P3 EXP1. Endopod largely as in P2 except for one inner seta only on P3 ENP2 and two inner setae on P3 ENP3.

P4 ( Fig. 7B ). With intercoxal sclerite, praecoxa, coxa and basis as in P3. Exopod longer than endopod; EXP: ENP length ratio 1.3; largely as in P3 except for two inner setae on P4 EXP3 of which distalmost one visibly thicker and strongly pectinate. Endopod reaching slightly beyond middle of EXP3; largely as in P3 except for stiffer inner seta on P4 ENP2, and one inner seta only on P4 ENP3.

Armature formula of P1–P4 as follows: P5 ( Fig. 2B ). With outer seta of BENP arising from long setophore. Endopodal lobe triangular, reaching middle of exopod; with small spinules along outer margin and at base of inner setae; with five elements – one outer subdistal, one apical and one inner subdistal normal seta, and two inner bifurcate elements. Exopod elongate, 2.8 times as long as wide; with spinules along inner margin and with few proximal outer spinules; with six elements – three outer slender, short setae, two apical elements, of which outermost one shorter, and one inner seta.

P6 ( Fig. 2A ). With three setae – one short bipinnate element, and one medial and one inner bare seta of which medial one shorter.

Male

GENERAL. Total body length measured from tip of rostrum to posterior margin of caudal rami ranging from 675 to 900 µm (mean 731 µm; n = 5; total body length of allotype 680 µm).

PROSOME ( Fig. 8A ). As in female.

UROSOME ( Fig. 8A–B ). As in female except for second – P6-bearing somite – and third urosomites separated, and for continuous spinular rows and hyaline frill of third and fourth urosomites ventrally.

SEXUAL DIMORPHISM. Expressed in the ventral somatic ornamentation, antennule, basis of P1, P2 ENP, P5 and P6.

ANTENNULE ( Fig. 9A–B ). Ten-segmented, haplocer. All segments smooth; first and second segments with tube pore. All setae smooth except for two and three biarticulated setulose setae on ninth and tenth segments, respectively; outer subdistal seta of tenth segment biarticulated basally, neighbouring seta swollen basally. Armature formula: 1(1); 2(11); 3(5); 4(3); 5(7 +(1+ae)); 6(1); 7(1 +2 spines); 8(1 +2 spines); 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 basis without slender inner, long spinules, and with three inner accessory spines and a proximal inner, nose-like outgrowth in the male ( Fig. 9C ).

P2 EXP (not shown). As in female. Endopod ( Fig. 10A ) sexually dimorphic, two-segmented; ENP1 0.7 times length of ENP2, with sinuous inner margin, with proximal and medial outer slender spinules, with one short inner seta; ENP2 oval, with longitudinal row of outer slender, long spinules, with two short inner setae arising from pedestal, subdistally with one posterior strong, blunt element, and with one anterior stiff, bare seta with subapical rounded expansion and pointed tip, 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. 10B ). With outer seta of baseoendopod arising from long setophore. Endopodal lobe reaching middle of exopod, with inner and outer spinules as shown, with two distal bifurcate setae of which outermost one slightly shorter. Exopod rectangular, 2.5 times as long as wide, with longitudinal row of inner spinules and medial pore, with few proximal outer spinules, with six setae – three outer elements of which proximalmost visibly longer, one subdistal outer seta arising from setophore and two distal setae of which innermost one ⅓ length of outermost and with bifurcate tip.

P6 ( Fig. 8B ). Asymmetrical, each leg with three setae of which innermost one shortest and spiniform, medial and outermost ones slender, medial one longest.

Variability

The left dorsal sensilla of the anal somite of the holotype is situated more proximally than the right sensilla. One female possesses five instead of six setae on one mandibular endopod and two instead of three maxillary endites on one maxilla.

Figures

Fig. 1. Typhlamphiascus medici sp. nov., holotype, ♀ (ICML-EMUCOP-180119-40). A. Habitus, dorsal view. B. Anal somite and caudal rami, dorsal view. C. Habitus, lateral view. D. Anal somite and left caudal ramus, lateral view.

Fig. 2. Typhlamphiascus medici sp. nov., paratype, ♀ (ICML-EMUCOP-180119-41). A. Urosome, ventral view (P5-bearing somite omitted). B. P5, anterior view.

Fig. 3. Typhlamphiascus medici sp. nov., paratype, ♀ (ICML-EMUCOP-180119-41). A. Rostrum and antennule (armature omitted for simplicity; arrows indicate tube pores on first and second segments). B. Rostrum and antennule showing armature. C. Antenna with aberrant outermost geniculate seta (without spinular ornamentation), and with only two free geniculate setae. D. Free endopodal segment of another antenna.

Fig. 4. Typhlamphiascus medici sp. nov., paratype, ♀ (ICML-EMUCOP-180119-41). A. Mandible. B. Maxillule.

Fig. 5. Typhlamphiascus medici sp. nov., paratype, ♀ (ICML-EMUCOP-180119-41). A. Maxilla. B. Maxilliped.

Fig. 6. Typhlamphiascus medici sp. nov., paratype, ♀ (ICML-EMUCOP-180119-41). A. P1, anterior view. B. Intercoxal sclerite of P1, anterior view. C. P2, anterior view.

Fig. 7. Typhlamphiascus medici sp. nov., paratype, ♀ (ICML-EMUCOP-180119-41). A. P3, anterior view. B. P4, anterior view.

Fig. 8. Typhlamphiascus medici sp. nov. A. Allotype, ♂ (ICML-EMUCOP-180119-43); habitus, dorsal view. B. Paratype, ♂ (ICML-EMUCOP-180119-44); urosome, ventral view (P5-bearing somite omitted).

Fig. 9. Typhlamphiascus medici sp. nov., paratype, ♂ (ICML-EMUCOP-180119-44). A. Rostrum and antennule (armature omitted for simplicity). B. Rostrum and antennule showing armature. C. P1 basis, anterior view.

Fig. 10. Typhlamphiascus medici sp. nov., paratype, ♂ (ICML-EMUCOP-180119-44). A. P2 ENP. B. P5, anterior view.

Armature formula of P1–P4 as follows: P5 ( Fig. 2B ). With outer seta of BENP arising from long setophore. Endopodal lobe triangular, reaching middle of exopod; with small spinules along outer margin and at base of inner setae; with five elements – one outer subdistal, one apical and one inner subdistal normal seta, and two inner bifurcate elements. Exopod elongate, 2.8 times as long as wide; with spinules along inner margin and with few proximal outer spinules; with six elements – three outer slender, short setae, two apical elements, of which outermost one shorter, and one inner seta.