Philometra epinepheli, Dewi, Kartika & Palm, Harry W., 2013

Dewi, Kartika & Palm, Harry W., 2013, Two new species of philometrid nematodes (Nematoda: Philometridae) in Epinephelus coioides (Hamilton, 1822) from the South Bali Sea, Indonesia, Zootaxa 3609 (1), pp. 49-59 : 53-56

Philometra epinepheli sp. nov.

Taxonomy summary

Type host: Epinephelus coioides (Hamilton, 1822) ( Serranidae ; Perciformes )

Site of infection: opercula

Type locality: South Bali Sea, Indonesia

Date of collection: July 2008

Collector: Sonja Kleinertz (Aquaculture and Sea-Ranching, Faculty of Agricultural and Environmental Sciences, University Rostock, Germany)

Specimens deposited: Holotype (MZB Na 487), 5 female paratypes (MZB Na 488)

Host: Epinephelus coioides (Hamilton, 1822) ( Serranidae ; Perciformes )

Etymology: Species epithet is derived from the generic name of the host fish, Epinephelus .

Gravid female (n=6) — Medium sized nematodes. Total body length 7.75–17.80 (12.32) mm, maximum width 340–550 (442), smooth cuticle striation 8.0–9.0 (8.6) apart. Head end bluntly rounded with inscopius papilla, width 72.6. Oral aperture circular, diameter 30.3, surrounded with 14 spherical very small cephalic papillae arranged in PLATE 3. Philometra epinepheli sp. nov. (SEM figures): M. cephalic end (apical view), N-O. Small cephalic papilla, P. Mouth with amphid, Q. Larva and eggs, R. Posterior end with two lateral caudal projections. c - cephalic papilla; a - amphid; cp - caudal projection.

two circles; internal circle consisting of four submedian and two lateral single papilla, external circle formed by four pairs of sub median papillae. Two small lateral amphids present near circular oral aperture. Bottom mouth formed by flat surface of three oesophageal sectors. Nerve ring 180–230 (203). Anterior oesophagus swollen near mouth, forming muscular bulb. Cephalic papillae hardly visible. Overall length of oesophagus 930–1,210 (1,036), representing 6.80–12.0% (8.40%) of TBL, consisting bulb 75–100 (88.5) long, 88–120 (102) wide and narrow, muscular oesophagus 850–1,100 (947) long, 55–70 (58) wide. Oesophageal gland poorly developed, with large nucleus posteriorly. Nucleus of oesophageal gland 750–980 (835) from anterior end. Ventriculus 49 long and 47 wide. Vulva and anus atrophied. Ovaries long, placed in the posterior body. Uterus occupying most available space in the body, posteriorly filled with numerous eggs, towards anterior gradually filled with larvae, fully developed larvae in the anterior end of uterus. Larvae 340–360 long, wide 0.012–0.014. Eggs spherical; unembrionated eggs 15.6–41.6 by 13–26, embrionated eggs 49–52 by 31.2–34.0. Body end bluntly rounded, provided with two lateral caudal projections.

PLATE 4. Philometra epinepheli sp. nov. (line drawings): S. Cephalic end (apical view), T. Anterior part of the body, U. Anterior end, lateral view; V and W: caudal end, lateral and ventral views X: Posterior end.

Male: unknown.

Remarks. Philometrids show a relatively high degree of host specificity (Moravec & Justine 2008). Consequently, a possible post mortem migration of the nematodes is not considered. To date, more than 97 valid species of Philometra have been described (Moravec, Bakenhaster & Fajer-Avila 2010; Moravec et al. 2011; Moravec & Justine 2011). Some of them have been recorded also from the serranid genus Epinephelus , i.e P. managatuwo Yamaguti, 1941 , P. pinnicola (Yamaguti, 1935) , P. ocularis Moravec, Ogawa , Miyazaki & Donai, 2002, P. margolisi Moravec, Vidal-Martínes & Anguirre-Macedo, 1995 , P. salgadoi Vidal-Martínes , Aguirre- Macedo & Moravec, 1995, P. mexicana Moravec & Salgado-Maldonado, 2007 , P. cyanopodi Moravec & Justine, 2008 , P. fasciati Moravec & Justine, 2008 , and P. morii Moravec, Bakenhaster & Fajer-Avila, 2010 . Of them P. managatuwo , P. margolisi , P. cyanopodi , P. fasciati and P. mexicana infect the gonads, P. ocularis infects the ocular cavity, P. pinnicola infects the fins, whereas P. m o r i i infects the mouth cavity of the host (Moravec 2006; Moravec & Salgado-Maldonado 2007; Moravec & Justine 2008; Moravec et al. 2010). So far, no Philometra species has been recorded from the opercula as the preferred site of infection.

Some subcutaneous tissues of the head or the fins can be considered a similar infection site compared with the opercula. Only P. pinnicola has been recorded from the fins of E. akaara , a species from the Inland Sea, Japan. However, this species clearly differs from the new species in the absence versus the presence of protrusions at the posterior end of the gravid female. In addition, the area of distribution of the host species of P. epinepheli is different, compared with other Philometra species mentioned above; P. cyanopodi , P. ocularis , P. managatuwo , P. margolisi , and P. fasciati were recorded from New Caledonia, Pacific Ocean; P. mexicana , P. morii and P. s a l g a d o i from the southern Gulf of Mexico and Atlantic Ocean while P. pinnicola is found in the Inland Sea, Japan. Most recently a Philometra sp. was recorded from the mouth of E. areolatus by Kleinertz et al. 2012, however, at a low intensity not providing enough worms for a proper taxonomic treatment.

According to its morphology, the new species Philometra epinepheli sp. nov. can be distinguished from all congeners in having smaller gravid females except P. fasciati ; 7.75–17.80 mm in this species versus 19.34–30.07 mm in P. m or i i; 21.35–208.00 mm in P. cyanopodi ; 22–40 mm in P. pinnicola ; 30.292–96.086 mm in P. ocularis ; 65–85 mm in P. margolisi ; 178–230 mm in P. m e x i c a n a; and 445–460 mm in P. managatuwo (Moravec & Justine 2008; Moravec 2010; Moravec, 2006; Moravec & Salgado-Maldonado 2007). The gravid female of P. fasciati is unknown, but this species differs by the zoogeographical distribution (South Bali Sea versus New Caledonia). In addition, this is the first opercula-infecting species of Philometra described from the fish family Serranidae .