Proales amplus Yang & Min, 2024

Yang, Hee-Min & Min, Gi-Sik, 2024, Proales amplus sp. nov., a new monogonont rotifer with a large epipharynx from Korea (Rotifera, Proalidae), Biodiversity Data Journal 12, pp. e 129622-e 129622 : e129622-

Proales amplus Yang & Min sp. nov.

Materials

Type status: Holotype. Occurrence: catalogNumber: NIBRIV 0000909850 ; occurrenceID: CBCF2B2C-0172-52CB-A556-4677 FBD3267 E; Taxon: scientificName: Proales amplus ; phylum: Rotifera; family: Proalidae ; genus: Proales ; scientificNameAuthorship: Yang & Min; Location: island: Jeju island; country: South Korea; verbatimLatitude: 33 ° 25 ' 13 " N; verbatimLongitude: 126 ° 50 ' 42 " E; Event: eventDate: 09 Jan. 2022; Record Level: institutionCode: National Institute of Biological Resources ( NIBR)

Type status: Paratype. Occurrence: catalogNumber: NIBRIV 0000909851 ; occurrenceID: 62604C3B-E7C0-5DBE-BB2B-211A1E1D63A9; Taxon: scientificName: Proales amplus ; phylum: Rotifera; family: Proalidae ; genus: Proales ; scientificNameAuthorship: Yang & Min; Location: island: Jeju island; country: South Korea; verbatimLatitude: 33 ° 25 ' 13 " N; verbatimLongitude: 126 ° 50 ' 42 " E; Event: eventDate: 09 Jan. 2022; Record Level: institutionCode: National Institute of Biological Resources ( NIBR)

Type status: Paratype. Occurrence: catalogNumber: NIBRIV 0000909852 ; occurrenceID: 16040B1E-09DA-51CB-8EC7-8664 FE3064 AB; Taxon: scientificName: Proales amplus ; phylum: Rotifera; family: Proalidae ; genus: Proales ; scientificNameAuthorship: Yang & Min; Location: island: Jeju island; country: South Korea; verbatimLatitude: 33 ° 25 ' 13 " N; verbatimLongitude: 126 ° 50 ' 42 " E; Event: eventDate: 09 Jan. 2022; Record Level: institutionCode: National Institute of Biological Resources ( NIBR)

Type status: Paratype. Occurrence: catalogNumber: NIBRIV 0000909853 ; occurrenceID: 757532B6-2E54-56B4-BD14-011208DFCD69; Taxon: scientificName: Proales amplus ; phylum: Rotifera; family: Proalidae ; genus: Proales ; scientificNameAuthorship: Yang & Min; Location: island: Jeju island; country: South Korea; verbatimLatitude: 33 ° 25 ' 13 " N; verbatimLongitude: 126 ° 50 ' 42 " E; Event: eventDate: 09 Jan. 2022; Record Level: type: SEM preparation; institutionCode: National Institute of Biological Resources ( NIBR)

Type status: Paratype. Occurrence: catalogNumber: NIBRIV 0000909854 ; occurrenceID: 75CFAB69-4632-5DE3-A047-B4CE6C810DC3; Taxon: scientificName: Proales amplus ; phylum: Rotifera; family: Proalidae ; genus: Proales ; scientificNameAuthorship: Yang & Min; Location: island: Jeju island; country: South Korea; verbatimLatitude: 33 ° 25 ' 13 " N; verbatimLongitude: 126 ° 50 ' 42 " E; Event: eventDate: 09 Jan. 2022; Record Level: type: SEM preparation; institutionCode: National Institute of Biological Resources ( NIBR)

Description

Adult Female. Total length 277–303 μm (n = 5). Illoricated body soft, flexible, hyaline. Body slender, cylindrical, fusiform in dorsal and lateral views (Figs 2 , 3 , 4 ). Head distinguished from trunk by transverse fold in dorsal view. One dorsal antenna located near posterior fourth of head (Fig. 4 A). Rostrum short, broad, semicircle (Fig. 4 C). Corona oblique or slightly ventral, extending from anterior margin to ventral side of head (Fig. 4 B and C). Brain saccate, large, occupying most of the head region dorsally (Figs 2 , 3 A). Retrocerebral sac absent. Two tiny red eyespots on the brain, positioned very close together and displaced to the right (Fig. 3 D). Trunk with six transverse folds, several longitudinal folds dorsally in the middle. A pair of lateral antennae at the middle of trunk (Fig. 4 A). Tail short, wide, distally rounded, covering half of foot. Foot with one pseudosegment, short, approximately 1 / 20 of total length. Toes symmetrical, short, slim, blunt ends, 10–11 μm in length (Fig. 3 F). Toes straight in dorsal view, slightly curved upwards in lateral view (Fig. 3 C). Pedal glands symmetrical, large, kidney-shaped, exceeding beyond foot length. Vitellarium with eight nuclei.

Digestive organs. Mouth somewhere at the posterior end of the ventral side of the corona. Oesophagus thin, long, passing between brain and mastax, connecting mouth and stomach along dorsal side (Suppl. material 1). Both stomach and intestine hyaline, difficult to distinguish. Gastric glands very large, elongated pyriform, located antero-dorsal to stomach (Fig. 3 E). Bladder oval-shaped, moderate size when filled. Salivary glands and cloaca not observed.

Trophi. Malleate type, almost symmetrical (Fig. 5 A). Rami without alulae on lateral side in dorsal view; ventral view with a pair of blunt projections proximally; inner margin smooth, without projections or scleropili; a pair of oval-shaped basifenestrae in the middle on both dorsal sides of ramus (Fig. 5 A and E). Fulcrum short, thin, straight, rod-shaped in dorso-ventral view, without expansion at posterior end; 5.0–6.1 μm in length, approximately 1 / 3 the length of manubria (Fig. 5 A) Unci 7.5–8.4 μm in length; symmetrical with five teeth; teeth composed of three large and two small, increasing in size dorsally to ventrally; pre-uncinal tooth at the largest unci teeth (Fig. 5 D and E). Manubria 13.1–14.9 μm in length; symmetrical, clubbed shape, gradually narrowing anteriorly to posteriorly; anterior end blunt, slightly expanded; one groove located anteriorly on dorsal side; middle part of manubria slightly twisted outwards; posterior end blunt, sharply tapered, curved dorsally (Fig. 5 B and C). Epipharynx asymmetrical, large, wide and flat; anterior margin comb-like-shaped; posterior base with a width of 1 / 3 of anterior margin, extending to the middle of the ventral side of rami; proximal anterior side of right epipharynx extending towards left (Fig. 5 A and E).

Male and eggs unknown.

Diagnosis

Body slender, fusiform. Head distinguished from trunk by transverse fold. Two tiny red eyespots on the brain positioned very close together displaced to right. Trunk with six transverse folds, several longitudinal folds dorsally in the middle. Foot short, with one pseudosegment. Toes short, slim, ending in blunt tips. Pedal glands large, exceeding foot in length. Gastric glands very large, elongated, pyriform. Trophi malleate. Rami without alulae, with a pair of blunt projections located proximally. Fulcrum short, thin, rod-shaped in dorso-ventral view. Unci with five teeth, comprising three large teeth and two small teeth. Preuncinal tooth at the largest unci teeth. Manubria club-shaped, slightly twisted, posterior end curved dorsally. Epipharynx large, wide, flat, with comb-like shape at apical margin; posterior base with a width of 1 / 3 of anterior margin, extending to the middle of the ventral side of rami; proximal anterior side of right epipharynx extending towards left.

Etymology

The specific name amplus is derived from the Latin word amplus , meaning large or broad, referring to the size and shape of the epipharynx.

Molecular data

Partial sequences of four genes (COI, 18 S rDNA, 28 S rDNA and ITS 1) from three specimens were obtained. Intraspecific variations were not found in any of the genes. The corresponding GenBank accession numbers for each of these gene sequences are as follows: COI, 660 bp ( PP 750787 – PP 750789 ); 18 S rDNA, 1644 bp ( PP 751790 – PP 751792 ); 28 S rDNA, 780 bp ( PP 751742 – PP 751744 ); and ITS 1, 324 bp ( PP 751753 – PP 751755 ).

Phylogenetic analysis

To calculate the genetic distances of Proales species, five sequences each of COI and 18 S rDNA, and four sequences of 28 S rDNA were used (Table 2 ). The genetic distances between the Proales species ranged from 0.249 –0.340 for COI, 0.018 –0.041 for 18 S rDNA and 0.160 –0.254 for 28 S rDNA (Table 3 ). The new species exhibited significant genetic distances from other Proales species in all three genes, supporting that the species is not only morphologically, but also molecularly a new species. As for ITS 1, it was not possible to calculate the genetic distances between Proales species, as this marks the first online presence of ITS 1 sequences for Proalidae . Given the recent use of the ITS 1 region as a useful marker in species diversity studies, we have provided ITS 1 sequences for the new species ( Papakostas et al. 2016, Kordbacheh et al. 2017, Mills et al. 2017, Kordbacheh et al. 2018).

The 18 S rDNA Maximum-Likelihood (ML) phylogenetic tree was constructed, based on seven Proalidae species, two Epiphanes species and one Synchaeta Ehrenberg, 1832 as an outgroup (Fig. 6 , Table 2 ). The new species, Proales amplus sp. nov., formed a clade with P. fallaciosa ( MT 522678 ) with high support (SH-aLRT = 96.7, bootstrap value = 95). Within the Proalidae clade, the genus Proales did not form a monophyletic group. Bryceella stylata ( MT 522631 ) formed a clade with P. doliaris ( DQ 297717 ) and Wulfertia ornata ( MT 522695 ) formed a clade with P. similis ( DQ 297719 ), both with low support values. Epiphanes daphnicola , formerly classified as Proales , was clearly separated from the other Proalidae species and formed a clade with Epiphanes senta ( DQ 089735 ) with high support (SH-aLRT = 96.6, bootstrap value = 99), consistent with the previous results of Wilts et al. (2012).

Figures

Figure 2. Line drawing of Proales amplus sp. nov., dorsal view. Scale bar: 100 μm.

Figure 3. Live specimen of Proales amplus sp. nov. observed under the optical microscope. A lateral view; B dorsal view; C ventral view; D eyespots and mastax; E gastric glands, dorsal view; F bladder and foot glands. Scale bars: A – C = 100 μm, D, F = 20 μm, E = 50 μm. Abbreviations: bl = bladder, br = brain, ey = eyespots, fg = footglands, fo = foot, gg = gastric glands, in = intestine, mx = mastax, nu = nuclei, t = toe, vi = vitellarium.

Figure 4. SEM image of the habitus of Proales amplus sp. nov. A dorsal view; B ventral view; C lateral view, right side. Scale bar: 30 μm. Abbreviations: co = corona, da = dorsal antenna, la = lateral antenna, t = toe.

Figure 5. SEM image of the trophi of Proales amplus sp. nov. A dorsal view; B left manubrium, outside view; C left manubrium, inside view; D unci and rami, dorsal view; E unci and rami, ventral view, arrow indicates the extension of the right epipharynx. Scale bar: 5 μm. Abbreviations: bf = basifenestra, ep = epipharynx, fu = fulcrum, gr = groove, ma = manubrium, pt = pre-uncinal tooth, ra = ramus, un = uncus.

Figure 6. Maximum-Likelihood (ML) tree of Proalidae and Epiphanes species, based on 18 S rDNA, using the GTR + F + I + R 2 model. Values on the nodes represent SH-like approximate likelihood ratio and ultrafast bootstrap support. The scale bar indicates branch length as the number of nucleotides substitutions per site.