Trypetesa habei Utinomi, 1962

Chan, Benny K. K., Cheang, Chi Chiu, Chen, I-Han & Kolbasov, Gregory A., 2013, Acrothoracican barnacles (Lithoglyptida) in Taiwan, including the taxonomic status of Balanodytes taiwanus Utinomi, 1950 and cryptic diversity of Auritoglyptes bicornis (Aurivillius, 1892), Zootaxa 3694 (3), pp. 221-239 : 233-236

Trypetesa habei Utinomi, 1962

Figure 6 B

Trypetesa habei Utinomi, 1962: 399 . — Tomlinson 1969: 129, fig. 35. — Kolbasov 2009: 334, fig. 116.

Material examined. CEL-Acro-sp-261, 1 specimen, in Drupa ricinus occupied by a hermit crab, He-Ping-Dao, Keelung, Taiwan, 9 July 2010.

Diagnosis. (Female) Burrow opening oval, extending as fine narrow slit ( Fig. 6 B); opercular bars smooth, without teeth or conspicuous denticles ( Fig. 6 B); 3 pairs of terminal cirri, uniramus, 4 joined; caudal appendages absent, mantle sac with orifical knob and 2 palps ( Fig. 6 B).

Geographical distribution. Japan, Taiwan.

Remarks. This represents a new record for Taiwan.

Molecular analysis

A total of 25 and 28 partial sequences were obtained for COI (454–469 bp) and 16S (508–16 bp), respectively, from 28 specimens of the six species ( Tables 1 , 2 ). COI (h: 0.99 ± 0.01; π: 0.1881 ± 0.0100) exhibits 196 polymorphic sites (179 parsimony informative sites, PIS), while 16S (h: 0.94 ± 0.03; π: 0.17 ± 0.01) demonstrates 183 PIS out of 193 polymorphic sites. Excluding T. habei (due to a single sample), although all five species show high haplotype diversities in the COI dataset, A. bicornis shows the highest nucleotide diversity ( Table 2 ). Additionally, A. bicornis demonstrates the highest haplotype and nucleotide diversities in 16S ( Table 2 ) and intraspecific K2P genetic distances for both genes ( Table 3 ) among all the acrothoracican species. The pairwise K2P distances among species, ranging from 0.132 to 0.288, are relatively uniform compared to the intra-specific distances. From the phylogenetic trees based on the both 16S ( Fig. 7 A) and COI ( Fig. 7 B) genes, although the statistical supports of the inter-specific relationship are relatively low, each species by their own form a highly significant clade ( Fig. 7 ).

N, total number of specimens examined; n, number of sequences obtained; length, the aligned length of the markers; n h, number of haplotypes; H, haplotype diversity; π, nucleotide diversity; and N.A., not applicable. Collection site of acrothoracican species. Refer to text. Kochlorine hamata was collected in Phuket, Thailand for comparative studies in the present study.

Specimens of B. taiwanus from different substrata, including barnacle and gastropod shells and dead coral skeletons, clustered in the same clade and the differences in K2P distance between specimens from different substrata were <1%.

In Auritoglyptes , specimens from He-Ping-Dao, Keelung, Taiwan formed three distinct clades in the 16S and COI tree ( Fig 7 ). K2P differences among the three clades in the 16S region reached>7%. This differentiation is concordant with the high genetic diversity and the high intra-specific genetic distances observed in this species.

Bt, Balanodytes taiwanus ; Au, Auritoglyptes bicornis ; Be, Berndtia purpurea ; Ko, Kochlorine hamata ; Li, Lithoglyptes sp.; Tr, Trypetesa habei ; and N.A, not applicable.

Figures

FIGURE 6. Auritoglyptes and Trypetesa from Taiwan. (A) Auritoglyptes bicornis (Aurivillius, 1892). Opercular bars of females from three genetic clades revealed from molecular analysis. (B) Trypetesa habei Utinomi, 1962 showing burrow opening and external view of female. Abbreviations: ob — opercular bar, obp — posterior process of opercular bar, ok — orificial knob, p — palps of mantle sac, sp — setose process of operculum (auricle). Scale bars in Μm.

FIGURE 7. Phylogenetic neighbor joining (NJ) tree of: (A) 16 S and (B) Cytochrome oxidase subunit I (COI) region of lithoglyptid barnacles collected in present study, based on K 2 P genetic distance. The topologies of NJ and maximum likelihood (ML) trees are identical for 16 S, and with inconsistency (dash line as ML tree) for COI. Bootstrap statistical significance was shown on the branches; those less than 50 were not indicated.

Tables

TABLE 2. Sample size and genetic diversity of the five acrothoracican species studied. Please note that no diversities can be calculated for Trypetesa habei due to a single sample.

n		Length
Species N COI	12S	COI	16S
Balanodytes taiwanus 8 7	8	469	511–513
Lithoglyptes sp. 4 4	4	469	515–516
Berndtia purpurea 4 4	4	469	508–509
Auritoglyptes bicornis 7 5	7	469	509–519
Kochlorine hamata 4 4	4	469	511–513
Trypetesa habei 1 1	1	454	508

TABLE 3 Kimura- 2 - parameter genetic (K 2 P) distances within and between each acrothoracican species studied. Please note that no intra-specific K 2 P distances can be calculated for Trypetesa habei due to a single sample.

COI	Bt	Au	Be	Ko	Li	Tr
Bt	0.007
Au	0.298	0.193
Be	0.247	0.285	0.018
Ko	0.250	0.296	0.281	0.002
Li	0.213	0.241	0.220	0.222	0.001
Tr	0.272	0.328	0.246	0.334	0.255	NA
16S	Bt	Au	Be	Ko	Li	Tr
Bt	0.001
Au	0.257	0.104
Be	0.288	0.256	0.004
Ko	0.233	0.180	0.270	0.001
Li	0.237	0.190	0.228	0.132	0.001
Tr	0.218	0.247	0.259	0.232	0.207	N.A.