Herpyllobius hourdezi Suárez-Morales and Salazar-Vallejo, 2025

Suárez-Morales, Eduardo & Salazar-Vallejo, Sergio I., 2025, Expanding territories: new host records and four new species of herpyllobiid parasitic copepods (Copepoda: Herpyllobiidae) from Papua New Guinea deep-water polynoid polychaetes (Annelida: Polynoidae), Journal of Natural History 59 (13 - 16), pp. 1017-1047 : 1026-1028

Herpyllobius hourdezi Suárez-Morales and Salazar-Vallejo sp. n.

( Figures 6 , 7 )

Material examined

Holotype. ( MNHN-IU 2023-501)), adult ovigerous female, from Harmothoe samadiae sp. n., Papua New Guinea, Cape Croisiles, RV Alis, Sta. CP 4033 (04°52 ʹ 06.8412” S, 145° 52 ʹ 36.9228” E), 780 m, coll. 16 December 2012, S. Samadi, leg. ( MNHN 2001-170), ethanol-preserved, vial.

Type locality

Papua New Guinea, Cape Croisiles , RV Alis, Sta . CP4033 (04°52 ʹ 06.8412” S, 145°52 ʹ 36.9228” E), depth = 780 m.

Etymology

The species name is an eponym honouring Dr Stéphane Hourdez (Banyuls Oceanographic Observatory in Southern France), who first processed the deep-living polynoids herein reported. Gender is masculine.

Diagnosis

Female Herpyllobius with pear-shaped ectosoma, tapering towards genital area. Genital area with pair of prominent, sclerotised genital swellings with attached egg sacs. Genital swellings separated by depressed margin; intergenital surface lacking sclerotised dots. Ectosomal integument smooth, translucent. Ectosoma and endosoma connected by short stalk originating on underside of ectosoma, close to mid-body. Endosoma with proximal mass extending into two digitiform processes and single, distally twisted process with simple margins. Egg sacs thick, about 4 times as long as wide, multiseriate, with 6–8 rows of eggs.

Description of holotype adult female

Ectosoma roughly pear-shaped, 1.2 mm at maximal width, 956 μm high in anterior section, 0.87 mm in posterior section ( Figure 6 (A–D)). Ectosomal integument smooth, with thin, translucent cuticle showing inner whitish eggs mass ( Figure 7 (A, B)). Genital area with pair of heavily sclerotised, ring-shaped genital swellings (diameter = 245 µm each) (gs in Figure 6 (C)); intergenital area with smooth, depressed margin narrower than genital swellings diameter (arrowhead in Figure 6 (C)). Genital swellings with attached egg sacs (gs in Figure 6 (A, B)).

Paired genital swellings sclerotised, prominent, each rounded, slightly asymmetrical, about 255 μm each, swellings separated medially by smooth depression measuring almost 180 μm (arrows in Figure 6 (C, D)). Genital swellings of holotype each carrying egg sac. Egg sacs thick, cylindrical, 1 mm long, 0.45 mm wide. Intersomital stalk short, thick, 130 μm in diameter, originating on underside close to mid-body (stk in Figure 6 (B)). Endosoma 1.3 mm long, with two sections, proximal half anvil-shaped mass, 1.3 mm wide. Distal half with several intermediate lobes (L 1–4 in Figure 6 (B)), and curved subtriangular distal lobe (DL in Figure 6 (B)), 125 μm wide. Egg sacs barrel-shaped, paired, multiseriate, with up to 8 egg rows (es in Figure 6 (A–C)), eggs 65–85 μm in diameter.

Remarks

The new species H. hourdezi lacks a medial intergenital protuberance and sclerotised dots on the ectosoma, so it can be assigned to Group III (sensu Lützen and Jones 1976, López-González et al. 2000). This group originally contained a single species, H. haddoni Lützen 1964 , which is characterised by the absence of intergenital sclerotised dots or bulging processes (Lützen 1964; López-González et al. 2000). The group was recently expanded by Suárez-Morales and Salazar-Vallejo (2022) with the addition of five more species: H. luetzeni López-González, Bresciani and Conradi, 2000 , H. nipponicus Lützen, 1964 , H. cluthensis Boxshall, O’Reilly, Sikorski and Summerfield, 2019 , H. polarsterni López-González, Bresciani and Conradi, 2000 , and H. stocki López-González, Bresciani and Conradi, 2000 . With the addition of H. chambardi sp. n., Group III now comprises seven species; the new species can be distinguished from Group III congeneric species by the structure and details of the endosoma. Herpyllobius cluthensis has a distinctively long, depressed endosoma ( Boxshall et al. 2019), H. luetzeni has a massive bilobate endosoma, thus diverging from that described herein for H. depressus ; H. nipponicus also diverges from the new species by its possession of a disc-like multilobate endosoma; in H. polarsterni the endosoma is lump-like, with roughly wrinkled surface, clearly diverging from H. hourdezii ’s endosoma traits. We regard these differences sufficient to justify the proposal of a new species of Herpyllobius .

Figures

Figure 6. Herpyllobius hourdezi sp. n., holotype female from Harmothoe samadiae sp. n. (A) habitus, right lateral view showing ectosoma (ect), endosoma (end) and egg sacs (es). (B) same, left lateral view. (C) posterior view showing genital ectosoma (ect), endosoma (end), genital swellings (gs), egg sacs (es) and depressed intergenital margin (arrowhead). (D) same, close-up of depressed intergenital margin (arrow). Scales as shown.

Figure 7. Harmothoe samadiae sp. n. (A) non-type specimen (MNHN IA 2021–82) with attached H. hourdezi, ventral view, after Shirlastain-A. (B) Close-up of two ovigerous specimens of H. hourdezi. Scale bars: A = 1.3 mm; B = 0.3 mm.