Aetohemecus kirstenjensenae, Warren & Bullard, 2021

Warren, Micah B. & Bullard, Stephen A., 2021, Fish blood flukes (Digenea: Aporocotylidae) from Indonesia: Two new genera and species infecting the banded eagle ray, Aetomylaeus nichofii (Bloch and Schneider, 1801) Capape´and Desoutter, 1979 (Myliobatiformes: Myliobatidae) from Borneo, International Journal for Parasitology: Parasites and Wildlife 15, pp. 43-50 : 45-47

publication ID	https://doi.org/ 10.1016/j.ijppaw.2021.02.002
persistent identifier	https://treatment.plazi.org/id/039287F2-FF9F-FFCD-FCAF-10ADE5ACFA8C
treatment provided by	Felipe
scientific name	Aetohemecus kirstenjensenae
status	sp. nov.

Treatment

3.2. Aetohemecus kirstenjensenae View in CoL n. sp. ( Figs. 1–2 View Fig )

3.2.1. Diagnosis of adult specimens (based on four whole-mounted specimens; USNM coll. nos. 1642775-1642778)

Body 1000–1320 (1121 ± 152, 4) long, 235–245 (240 ± 4, 4) at greatest width, 4–6 × longer than wide ( Fig. 1 View Fig ). Lateral tegumental spines 93–120 (106 ± 12, 3) per side of body or a total of 189–228 (210 ± 20, 3), ending 18–38 (27 ± 10, 4) or 1–3% (2 ± 0.09, 3) of body length from posterior end of body, base slightly bifurcate at posterior margin, tissue not associated with base on anterior-most lateral tegumental spines ( Fig. 1 View Fig ), approximately equal in size throughout length of body; lateral tegumental spines in anterior region 7–8 (7.7 ± 0.5, 4) long, 1–2 (1.6 ± 0.5, 4) wide; mid-body 5–7 (6 ± 1, 4) long, 1–2 (1.2 ± 0.4, 4) wide, and posterior region 4–5 (4.5 ± 0.5, 4) long, 1 (1, 9) wide ( Fig. 1 View Fig ); peduncles supporting lateral tegumental spines approximately equal in size; anterior peduncles 7–8 (7.7 ± 0.5, 4) long, 3–5 (4 ± 0.8, 4) wide; mid-body and posterior peduncles 5–7 (6 ± 0.5, 4) long, 5–6 (5.5 ± 0.5, 4) wide.

Ventrolateral nerve-cord 924–1120 (995 ± 109, 3) long, 10–15 (12 ± 2, 4) wide near mid-body at widest level, 50–58 (53 ± 4, 4) from body margin. Primary commissure perpendicular to mid-line of body, connecting ventrolateral nerve-cords, 95–115 (105 ± 8, 4) or 8%–10% (9% ± 1, 4) of body length from anterior end of body, 25–28 (26 ± 1.5, 4) across width of worm, 10–18 (12 ± 4, 4) in breadth; ( Fig. 1 View Fig ); secondary commissure and nerve cords not evident in whole mounts.

Mouth 1–3 (2 ± 1.2, 3) in diameter, 1–8 (4 ± 4, 3) from terminal end of anterior sucker ( Fig. 1 View Fig ). Oesophagus 325–425 (379 ± 43, 4) in total length or 30%–37% (34% ± 0.03, 4) of body length, 18–23 (21 ± 2, 4) in maximum width, ventral to primary nerve-commissure ( Fig. 1 View Fig ); oesophageal wall thickening from 1 to 2 (1.5 ± 0.5, 4) near mouth to 5–10 (6.3 ± 2.5, 4) posteriorly. Caecal bifurcation 281–415 (355 ± 56, 4) or 21%–38% (32% ± 0.07, 4) of body length from anterior body end; anterior caeca 22–39 (31 ± 8, 4) in mean length or 2%–4% of body length, 21–27 (4) in mean width; posterior caeca 38–68 (57 ± 13, 4) in mean length or 4%–6% of body length, 19–34 (4) in mean width ( Fig. 1 View Fig ).

Testis 230–270 (250 ± 20, 3) long or 23%–25% (24% ± 0.01, 3) of body length, 53–85 (74 ± 15, 4) wide or 22%–35% (31% ± 0.06, 4) of body width, 3–5 (4 ± 0.9, 3) × longer than wide, post-caecal ( Fig. 1 View Fig ). Post-testicular space 335–380 (362 ± 20, 4) long or 29%–36% (33% ± 0.03, 4) of body length. Vasa efferentia comprising interconnecting meshwork of fine ducts entwined throughout testicular tissue, 8 (1) in diameter; vas deferens 118–210 (152 ± 40, 4) long, 8–18 (13 ± 4, 4) wide, emanating from postero-ventral portion of testis, curving dextrad ventral to anterior portion of ovary before curving mediad ventral to ovary to connect with cirrus-sac ( Fig. 2 View Fig ). Cirrus-sac 53–88 (64 ± 16, 4) long, having extremely thin wall approximately 1–2 (2 ± 0.5, 4) thick, including seminal vesicle and cirrus; seminal vesicle 45–75 (55 ± 14, 4) long, 13–15 (14 ± 1, 4) wide, filling breadth of cirrus sac, curving dextrad, narrowing and opening dorsal ( Fig. 2 View Fig ); everted cirrus long, 61 long or 1.8 × seminal vesicle length, 4 wide ( Fig. 1 View Fig ); internal cirrus 27 long or 37% of seminal vesicle length, 3 wide ( Fig. 2 View Fig ). Common genital pore 178–298 (227 ± 50, 4) or 18%–23% (20% ± 2, 4) of body length from posterior end of body, 50–58 (55 ± 3, 4) from sinistral body margin, 113–130 (123 ± 7, 4) from dextral body margin ( Figs. 1 and 2 View Fig ).

Ovary medial, lobed, 90–118 (102 ± 14, 4) long or 7%–11% (9% ± 0.01, 4) of body length, 63–100 (77 ± 16, 4) wide or 26%–42% (32% ± 0.07, 4) of body width, 0.9–1.6 (1.4 ± 0.3, 4) × longer than wide, post-caecal, post-testicular; post-ovarian space 205–253 (234 ± 20, 4) long or 18%–24% (21% ± 0.02, 4) of body length ( Figs. 1 and 2 View Fig ). Oviduct and Laurer’ s canal not evident; oviducal ampulla 10–20 (15 ± 7, 2) long, 15 (2) wide ( Fig. 2 View Fig ). Ootype ¨10–15 (13 ± 3, 3) in diameter, posterior to all genitalia ( Figs. 1 and 2 View Fig ). Vitellarium having follicles compacted in dense lobules, occupying space dorsal and lateral to oesophagus, caeca, and testis; common collecting duct 163–223 (196 ± 25, 4) long, 13–20 (17 ± 3, 4) wide.

Uterus extending anteriad from ootype ¨, 185–223 (207 ± 18, 4) long

or 17–20 (19 ± 0.01, 4) of body length, 58–93 (74 ± 16, 4) wide, with wall 1 (4) thick; ascending portion extending sinuously anteriad and dorsal to seminal vesicle, common vitelline duct, and ovary before extending anterior to ovary and connecting to descending portion, containing eggs in all (4) specimens ( Figs. 1 and 2 View Fig ); descending portion 80–105 (90 ± 11, 4) long or 36%–49% (44% ± 6, 4) of ascending uterus length, extending posteriad before connecting with metraterm; metraterm 30–58 (47 ± 14, 4) long or 11%–19% (16% ± 0.03, 4) of descending uterus, 8–15 (12 ± 3, 4) wide, comprising distal-most portion of female reproductive tract, demarcated from descending uterus by obvious constriction ( Fig. 2 View Fig ). Uterine eggs 10–13 (12 ± 1, 4) in diameter or 40%–67% (54% ± 0.1, 4) of uterus width, containing a large spheroid body plus several smaller, dense lipid-like bodies, with thin shell ( Fig. 2 View Fig ).

3.2.2. Taxonomic summary

Type and only reported host: Banded eagle ray, Aetomylaeus nichofii (Bloch and Schneider, 1801) Capape´and Desoutter, 1979 ( Myliobatiformes : Myliobatidae ).

Site in host: Heart lumen.

Type locality: Off Manggar, Makassar Strait, (01 ◦ 12 ′ 55.20 ′′ S, 116 ◦ 58 ′ 27.50 ′′ E), East Kalimantan, Borneo , Indonesia GoogleMaps .

Prevalence and intensity of infection: 1 (prevalence = 100%) banded eagle ray sampled on 3 August 2008 was infected by 4 specimens of A. kirstenjensenae .

Specimens deposited: Holotype ( USNM 1642775 About USNM ), paratypes ( USNM 1642776 About USNM , 1642777 About USNM , 1642778 About USNM ).

Etymology: The specific epithet “ kirstenjensenae ” honors Prof. Kirsten Jensen (Senior Curator of Invertebrate Zoology for the Biodiversity Institute and Natural History Museum; Associate Chair of Ecology and Evolutionary Biology at The University of Kansas, Lawrence, Kansas,

USA) for her contributions to our knowledge of elasmobranch parasites.

3.2.3. Taxonomic remarks

Aetohemecus kirstenjensenae is most similar to Selachohemecus benzi Bullard, Overstreet, and Carlson, 2006 , Selachohemecus olsoni Short, 1954 , and G. bulbosus by the combination of having a single row of Cshaped lateral tegumental spines, posterior caeca terminating in the middle 1/3 of the body, and an ascending and descending uterus ( Short, 1954; Bullard et al., 2006; Warren et al., 2019). Further, the new species is similar to G. bulbosus by having an oviducal ampulla and an ootype ¨ positioned posterior to the genitalia. Aetohemecus kirstenjensenae differs from S. olsoni and S. benzi by the combination of having an extruded cirrus that is as long as the seminal vesicle, an oviducal ampulla, a uterus that extends anterior to the ovary, and an o¨otype that is posterior to the genitalia. Aetohemecus kirstenjensenae differs from G. bulbosus by having a X- or H-shaped intestine, a uterus that extends anterior to the ovary, and an extruded cirrus that is as long as the seminal vesicle as well as by lacking an oesophogeal bulb (KEY) (Warren et al., 2019).

Aetohemecus kirstenjensenae further resembles several other fish blood flukes that infect chondrichthyans having large C-shaped spines ( Chimaerohemecus trondheimensis Van der Land, 1967 ; Hyperandrotrema cetorhini Maillard and Ktari, 1978 ; Hyperandrotrema walterboegeri Or´elis-Ribeiro and Bullard, 2013) ( Table 1). The new species differs from C. trondheimensis and Hyperandrotrema spp. by the combination of having a single row of C-shaped lateral tegumental spines (vs. two rows or a field of spines), an X- or H-shaped intestine (vs. inverse U-shaped) that terminates in the middle 1/3 of the body (vs. the posterior end of the body), a post-caecal ovary (vs. intercaecal), and post-caecal common genital pore (vs. intercaecal) (KEY) ( Van der Land, 1967; Maillard and Ktari, 1978; Orelis-Ribeiro et al., 2013).

Further, A. kirstenjensenae differs from other fish blood flukes that infect chondrichthyans in that those species lack lateral tegumental spines ( Achorovermis testisinuosus Warren and Bullard, 2020 ; Electrovermis zappum Warren and Bullard, 2019 ; Myliobaticola richardheardi Bullard and Jensen, 2008 ; Ogawaia glaucostegi Cutmore, Cribb, and Yong, 2018 ; and Orchispirium heterovitellatum Madhavi and Hanumantha Rao, 1970 ) ( Table 1). Until now, species of Selachohemecus were the only aporocotylids infecting chondrichthyans reported to have a X- or Hshaped intestine (KEY). Regarding the hosts for blood flukes, A. kirstenjensenae is the only nominal blood fluke reported from an eagle ray ( Myliobatidae ).