Amyzozercon chocoensis, Klompen & Gerdeman, 2023

Klompen, Hans & Gerdeman, Beverly S., 2023, Genus-level revision of the Heterozerconoidea (Parasitiformes: Mesostigmata), Zootaxa 5322 (1), pp. 1-66 : 22-23

Amyzozercon chocoensis new species

( Figs 2 , 4–5 , 21 , 25–26 , 45 , 55–56 , 73–77 ).

Diagnosis. As for the genus.

Description. Female idiosoma length 652 (43), width 560 (57) (N=5); male idiosoma length 566 (35), width 505 (44) (N=5). Complete measurements in Tables 3–4 .

Chelicera ( Figs 2 , 4–5 ). Basal part of fixed digit in female elongate, length width ratio 4–6. Movable digit in adults with thin, straplike dorsal extensions. Movable digit in female elongate, digit length>6 times basal width. Inside movable digit female with brush-like structure. Excrescences on male chelicera present, interdigital. Spermatodactyl on fixed digit of male chelicera present, of straight type.

Palp ( Fig. 21 ). Axial outgrowth of palp trochanter in female distinct and membranous. Axial outgrowth of palp trochanter in male absent. Seta pd1 on femur present. Setae on femur long, relatively thin, setiform. Setae al2 and pl on genu present. Number of sensilla on tarsus 10–11. Formula: 2–6–6–14–10/11.

Gnathosoma ( Figs 25–26 ). Gnathotectum of female without prominent points. Anterior margin gnathotectum serrate. Overall shape of gnathotectum intermediate between curved and blunt. Lateral lips enlarged to form a trough; posterior extension of the trough short, not extending beyond insertions of setae hyp2. Distance between setae hyp3 and sc subequal to that between hyp3 and hyp2. Setae hyp2 at least twice as long as hyp3. Cornicula membranous without a distal notch. Additional setal base-like structure on hypostome present.

Dorsum ( Fig. 45 ). Holodorsal shield in female covering most of the dorsum but leaving a wide strip of unsclerotized cuticle laterally and posteriorly, less so anteriorly. Holodorsal shield in male covering nearly entire dorsum. Peritrematal shield adjacent to dorsal shield but not fused to it. Anterior dorsal margin in adults with a single pair of elongate setae (j1) inserted on the anterior margin of the holodorsal shield. Antero-marginal area of dorsal shield in males without distinct spines. Median dorsal setae minute. Some posterior dorsal (Z2–Z4) and marginal (s6, S1–S3) setae elongate in both sexes. Of these, setae Z2–Z 3 in the females, and s6, Z2–Z 4 in the males on the shield.

Sternal area female ( Fig. 55 ). Areas near insertion sternal setae st1 sclerotized, forming isolated platelets. Sclerites of sternal setae st1 and st2 not fused. Sternal setae st1 and lyrifissures iv1 not on the same shield. Areas near insertion sternal setae st2 and st3 sclerotized, forming isolated platelets. Metasternal setae st4 present. Areas near insertion sternal setae st5 sclerotized, fused to genitiventral shield. Sternal lyrifissures iv 1 in adults present. Sternal lyrifissures iv 3 in female absent. Distinct curved, sclerotized ridge on anterior margin of female genital shield absent. Structures suggesting secondary genital openings not observed.

Sternal area male ( Fig. 56 ). Areas near insertion sternal setae st1 sclerotized, forming isolated platelets. Sternal setae st1 and lyrifissures iv1 not on the same shield. Sclerotized areas near insertions of sternal setae st2, st3 and st5 fused to sternitiventral shield. Sclerotized areas of sternal setae st2 and st3 completely fused. Sternal lyrifissures iv3 absent. Male genital opening anterior sternal, between coxae II. Genital shields not overlapping base of the tritosternum. Sternitiventral area in male smooth.

Opisthogaster ( Figs 55–56 ). Metapodal and sternitiventral shields in male not fused. Posterolateral margin of metapodal shields in adults rounded. Setae Zv3 present. Opisthogastral suckers absent. Ventral shield area in male with a single shield. Sternitiventral and anal shields in male not fused. Setae Sv2 and Sv3 not inserted on genitiventral (female) or sternitiventral (male) shields. Setae Sv2 and Sv 3 in female inserted in soft cuticle, in male inserted on margin metapodal shields. Setae Jv5 inserted anterior to ventrianal line. Insertion of paranal setae (pa) at level of anus. Postanal (po) seta of similar length as paranal (pa) setae. Setae Z5, S5, R5 and R 4 in both adults elongate. Marginal opisthosomal setae (other than elongate S -series setae) elongate. Postero-marginal shield in females small, not extending lateral to insertion setae R5.

Legs ( Figs 73–77 ). Tibiae and tarsi of legs I of similar width as the rest of the leg. Acrotarsus on legs I present. Femora I seta ad3 present. Femora I setae v3, v4 and pl2 absent. Genua I setae ad3 and pd3 absent. Tibiae I seta ad2 present, setae ad3, av2 and pv2 absent. Femora II setae av2 and pv2 absent. Genua II–IV setae ad3 and pl2 absent. Genua II seta pd3 absent, genua III–IV seta pd3 present. Tibiae II–IV setae ad2, pd3 and pl2 absent. Femora III seta v3 absent. Tarsi IV setae av4, pv4 absent. Complete chaetotaxy in Table 2 . Coxae I setae in male setiform. Femora I setae al1 and al2 setiform, in anterolateral position. Femora I seta av in male a large, curved spine; seta av in females a much shorter, straight spine ( Fig. 74 ). Femora II setae al, pl, av and pv in male setiform. Genua II seta pv and tibiae II seta pv in male setiform. Tarsi II seta pl1 setiform in both sexes. Trochanters III setae al, av and pl in male setiform.

Type depository: Holotype male at UNC Bogotá, accession number OSAL 106788 . Paratypes at ICN, OSAL, FMNH .

Material examined. Colombia, Chocó, Tutunendo, field station, 48m, 5.7494 N 76.5217 W, 30–Mar-2010, Jimeno, E., Correa, J. & Klompen, H., ex 2 male and 1 female Psammodesmus atratus in rotting log, host accession number ICN-MD-1525–7, UNC Bogotá, 1 male, OSAL 106788 (holotype). Same data, 1 female, OSAL 102659; 1 female, OSAL 102660; 1 male, OSAL 106721; 1 female, OSAL 106741; 1 male, OSAL 106781; 1 female, OSAL 106782; 1 female, OSAL 106783; 1 female, OSAL 106784; 1 female, OSAL 106785; 1 female, OSAL 106786; 1 female, OSAL 106787; 1 male, OSAL 106789; same locality, 25–Mar-2010, Mosquera, J. & Mosquera, M. E., ex male Psammodesmus atratus (Chamberlin) ( Polydesmida : Platyrhacidae ) in rotting log, host accession number ICN-MD-1525–2, UNC Bogotá, 1 female, OSAL 103952; 26–Mar-2010, Jimeno, E., Correa, J. & Klompen, H., ex mix of 1 female Psammodesmus atratus and 1 female P. sp. in rotting log, 1 male, OSAL 106736. Colombia, Chocó, Quebrada Taparral, 20km N of Palestina on Rio San Juan, 4.1500 N 77.0667 W, 26–Jan-1969, Malkin, B., ex Psammodesmus atratus , field code FMJK 71–1005 (host at FMNH), 1 female 2 males (FMNH). Colombia, Chocó, Caño Decordo, between Cucurrupi & Noanama on Rio San Juan, 4.5333 N 76.8667 W, 1–5–Jan-1969, Malkin, B., ex polydesmid millipede, field code FMJK 71–1006 (host at FMNH), 2 females 3 males (FMNH). Colombia, no further data, field code CM-14 (host at FMNH), 1 female 1 male (FMNH).

Etymology. This specific designation is a combination of Choco, the faunal region (and province) from which the species is described, and “ensis” Latin for “place, locality”.

Remarks. Amyzozercon chocoensis is somewhat unusual within Heterozerconidae by its association with polydesmid, rather than juliform, millipedes. We have a few single specimen records of Allozercon and Narceoheterozercon specimens from polydesmids, but these may be accidental. In contrast, Amyzozercon , Ecuazercon , and a few undescribed populations of Heterozercon (Jocelyn Martinez, pers. comm.) appear to be true polydesmid associates, recorded only from Polydesmida . At the Tutunendo site Amyzozercon chocoensis may be host specific, recorded only from Psammodesmus atratus (Chamberlin) (Platyrhacidae) . Examination of multiple specimens of Batodesmini sp.1 ( Polydesmida : Chelodesmidae ) (accession numbers ICN-MD-1527–1, -1527–2, -1527–3), a species that was equally common in the same rotting logs, never yielded Amyzozercon .

We have specimens of other species of this new genus (from Brazil, Ecuador, and (possibly) Honduras), but numbers are low and/or host and locality data for these collections are incomplete, limiting the value of added descriptions.

Figures

FIGURES 1–3. Chelicera females: 1, Discozerconidae, Discozercon derricki., female (OSAL 052739); 2, Heterozerconidae, Amyzozercon chocoensis, female (OSAL 106741); 3, Al. (Philippinozercon) makilingensis, female (OSAL 053222; blue arrow: brush like structure on inside movable digit). Abbreviations: pd: pilus dentilus. Red arrows: thin, strap-like extensions on the movable digit.

FIGURES 4–7. Heterozerconidae, chelicera males, photograph (top) and composite drawing (bottom): 4–5, Amyzozercon chocoensis (OSAL 106788); 6–7, Ecuazercon cushuimensis (FMNH-INS 4449621).

FIGURES 20–22. Left palp, adults: 20, Discozerconidae, Discomegistus sp., male (FMNH); 21; Heterozerconidae, Amyzozercon chocoensis, male (OSAL 106788); 22, Al. (Philippinozercon) makilingensis, male (OSAL 053267, redrawn from Gerdeman et al. (2018)).

FIGURES 23–26. Gnathosoma, adults: 23, Discozerconidae, Discozercon derricki, female (OSAL 052739); 24, Discozercon derricki, male (OSAL 004889); 25, Heterozerconidae, Amyzozercon chocoensis, female (OSAL 106787); 26, Amyzozercon chocoensis, male (OSAL 106721). Insets gnathotectum and labrum + salivary stylets. Abbreviations: LL, lateral lips.

FIGURES 45–47. Heterozerconidae, idiosoma dorsal: 45, Amyzozercon chocoensis, female (OSAL 106741); 46, Ecuazercon cushuimensis, female (FMJK 71–1118); 47, Afroheterozercon mahsbergi, male (OSAL 003042)

FIGURES 55–56. Heterozerconidae, Amyzozercon chocoensis, idiosoma venter: 55, female (OSAL 106741); 56, male (OSAL 102562).

FIGURES 73–77. Heterozerconidae, Amyzozercon chocoensis, legs: 73, leg I, male (OSAL 106736); 74, femur I, female (OSAL 106783), 75, leg II, male (OSAL 106736); 76, leg III, male (OSAL 106789); 77, leg IV, male (OSAL 106789).