Enchodelus longispiculus Guerrero, Liébanas & Peña-Santiago, 2008

Pedram, Majid, Pourjam, Ebrahim, Robbins, Robert T., Ye, Weimin & Santiago, Reyes Peña-, 2011, Description of one new, and new data on two known, species of Enchodelus Thorne, 1939 (Dorylaimida: Nordiidae) from Iran, Nematology 13 (6), pp. 729-740 : 730-734

Enchodelus longispiculus Guerrero, Liébanas & Peña-Santiago, 2008

MATERIAL EXAMINED

Thirty-nine females and 27 males from three localities.

MEASUREMENTS

See Table 2.

MOLECULAR STUDY

Ribosomal DNA near-full-length small subunit 18S gene, internal transcribed spacer and partial 5.8S gene of E. longispiculus were sequenced and deposited in GenBank under the accession number HM851184 . Blast search of the 2562 nucleotides yielded the highest match with other Enchodelus species. On the 18S, E. longispiculus had an identical sequence with E. babakicus voucher M32 from Iran ( FJ042952 ). The 18S of this species had 99% identity with E. macrodorus voucher M53 from Iran ( FJ042953 ) with 2 bp differences, Enchodelus sp. ( AY284793 ) with 5 bp differences, Enchodelus sp. ( AY284792 ) with 9 bp differences, Enchodelus sp. (EP207247) with 15 bp differences, and 97% identity with E. veletensis voucher M34 from Iran ( EU477379 ) with 35 bp differences and six gaps. However, the ITS1 region of E. longispiculus had considerable variation compared with three Iranian species including E. babakicus voucher M32 ( FJ042950 , identities = 601 / 725 (82.9%), gaps = 27 / 725 (3.7%)), E. macrodorus voucher M53 ( FJ042951 , identities = 568 / 729 (77.9%), gaps = 85 / 729 (11.7%)), and E. veletensis M34 ( EU477380 , identities = 353 / 672 (52.5%), gaps = 70 / 672 (10.4%)). These significant differences indicate that they are all distinct species. No ITS sequence data is available to compare for other Enchodelus species from GenBank. Figure 4 is a phylogenetic tree from a multiple alignment with 1693 total characters. This tree includes some dorylaimid species with a high match from the blast search result in GenBank. This tree is consistent with our previous results (Pedram et al., 2009a, b). Enchodelus longispiculus is identical to E. babakicus and they are in the same clade with E. sardashtensis sp. n., E. macrodorus and three other unidentified Enchodelus spp. with 100% support. This clade in the Nordiidae is sister to Eudorylaimus Andrássy, 1959 in Qudsianematidae , Epidorylaimus Andrássy, 1986 in Qudsianematidae and Prodorylaimus Andrássy, 1959 in Dorylaimidae . Enchodelus veletensis voucher M34 from Iran is not monophyletic with above-mentioned Enchodelus species. Figure 5 is a phylogenetic tree from a multiple alignment with only 638 total characters, so that all species in Enchodelus from GenBank can be included to examine their relationships. This tree is also consistent with our previous results (Pedram et al., 2009a, b) with two significant clades, viz. conical tail vs rounded tail (the clade to which E. longispiculus belongs). This tree shows that the 3 ļ portion of 18S is highly conserved. Many Enchodelus species share identical DNA sequences although they can be easily differentiated morphologically.

* Total range of several populations (taken from Guerrero et al., 2008a).

DISTRIBUTION

Found in three localities, in the rhizosphere of grasses, in Kaleibar, Eastern Azarbayjan, Chorreh village, Roudbar, Gilan province, and Astara, Gilan province, Iran. Collected in July, August and November, 2009.

REMARKS

The available data on E. longispiculus , i.e., its original description from the Iberian Peninsula (Guerrero et al., 2008b) and its subsequent report from Romania (Ciobanu et al., 2010), suggest that it might be a widely distributed species. It shows important intraspecific variations, especially in some morphometric features, e.g., body size (L = 1.07-1.87 mm), odontostyle length (24-34 µ m), vulva position (V = 41-51), etc. The three Iranian populations of the species herein studied fit well with those previously known, but it is morphometrically closer to Romanian material in its body size. Moreover, the range of some measurements is wider than that observed so far (although almost always overlaps it) in such parameters as lip region 13-15 µ m (vs 14-18 µ m in previous studies), body diam. at mid-body 40-55 µ m (vs 47-71 µ m) and tail length 15-37 µ m (vs 17-29 µ m).

This is the second report of the species in Asia, although the first one in Uzbekistan by Tulaganov and Usmanova (1978) is rather problematic since no description or illustration was provided (cf. Andrássy, in lit.).

Figures

Fig. 4. Bayesian consensus tree inferred from 18S under GTR + I + G model (lnL = 5297.7065; AIC = 10 615.4131; freqA = 0.2752; freqC = 0.2114; freqG = 0.2621; freqT = 0.2512; R(a) = 1.8482; R(b) = 5.0147; R(c) = 2.8536; R(d) = 0.2499; R(e) = 11.081; R(f) = 1; Pinva = 0.2089; Shape = 0.7502). Posterior probability values exceeding 50% are given on appropriate clades.

Fig. 5. Bayesian consensus tree inferred from 18S small under TVMef + I model (lnL = 1172.5674; AIC = 2355.1348; freqA = 0.2416; freqC = 0.1799; freqG = 0.2957; freqT = 0.2828; R(a) = 1.6906; R(b) = 8.6571; R(c) = 4.9786; R(d) = 0.5884; R(e) = 8.6571; R(f) = 1; Pinva = 0.6319; Shape = equal). Posterior probability values exceeding 50% are given on appropriate clades.