Hymeraphia elongata Picton & Goodwin, 2007

Hymeraphia elongata Picton & Goodwin, 2007 View in CoL

Fig. 10 View Fig

Hymeraphia elongata Picton & Goodwin 2007: 1448 View in CoL , fig. 5.

Material examined (3 specimens)

SWEDEN • 1 spec.; Svartejan ; 59.1102° N, 11.3219° E; 30 m depth; 11 Aug. 2018; Mats Larsson leg. [MM-180911-1]; SCUBA; LAR-180911-7154–7155; GenBank no.: OM436254 View Materials (coxI); voucher: GNM Porifera 1077 GoogleMaps • 1 spec.; same collection data as for preceding; 22 Dec. 2018; Mats Larsson leg. [MM-181222-1]; SCUBA; LAR-181222-8561, 8563, 8569; voucher: GNM Porifera 1078 GoogleMaps • 1 spec.; Bergylteskär ; 58.8289° N, 11.0831° E; 30 m depth; 9 Dec. 2018; Mats Larsson leg. [MM-181209-1]; SCUBA; LAR-181209-8302–8303, 8305; GenBank no.: OM436250 View Materials (coxI); voucher: GNM Porifera 1076 GoogleMaps .

Description

The three specimens have a thin incrusting morphology and were partially covered in silt. The surface is microhispid, and with visible pores and oscula. The oscula are elevated in a translucent chimney ( Fig. 10A View Fig ). The aquiferous system is partially visible at the surface. The colour in live specimens ranges from greyish-yellow ( Fig. 10B View Fig ) to orange-yellow ( Fig. 10A View Fig ) and changes to white when specimens are preserved in ethanol.

Skeleton

Megascleres are long tylostyles with an inflated head similar to the ones of acanthostyles ( Fig. 10C View Fig ), measuring 394.3– 850.3– 1275.7 ±311.5 ×3– 7.1 –12.5 ± 2.6 µm (N= 16). Additionally, there are long hair-like styles (common) or oxeas (rare) ( Fig. 10D View Fig ) with 184.7– 258.0– 321.5± 42.9 ×0.6– 1.5– 2.2± 0.4 µm (N =32) in size, and short acanthostyles with an inflated triangular head and shorts spines only at the tip ( Fig. 10E View Fig ), measuring 49.3– 89.9 –118.4 ± 21.3 ×7– 13.5– 16 ±2.3 µm (N=32).

Remarks

The major differences between H. elongata and H. stellifera are: the size of the spines in the acanthostyles, length of the anisoxeas, the colouration, and surface texture. The specimens of H. elongata present shorter spines in the acanthostyles and longer anisoxeas than what is reported for H. stellifera . Moreover, H. elongata presents a beige colour when alive and a smooth surface whereas H. stellifera ’s life colour is deep orange and a microshipid or vilose surface. In comparison, the acanthostyles in Hymeraphia breeni Picton & Goodwin, 2007 have few but longer spines at the tip, than what is reported for H. elongata or H. stellifera .

This species is a new record for Sweden, which is not surprising since the species was described in 2007. The specimens collected in Sweden present slightly shorter styles than what is reported for the type specimens ( Picton & Goodwin 2007), which might indicate the presence of regional differences or cryptic species. However, further studies are warranted to understand the order of inter- and intraspecific diversity, as well as micro-morphological diversity or plasticity within this genus. In fact, this is the first time that specimens of H. elongata are sequenced. In spite of morphological differences, the coxI sequences reveal at least two haplotypes with 1–2 bp differences, which show no clear distinction between H. elongata and H. stellifera ( Fig. 2 View Fig ). However, the lack of resolution using coxI is perhaps expected as this marker is known for having a substitution rate that is too low for adequate species discriminations (e.g., Erpenbeck et al. 2006). Therefore, future research is required to assess the validity of H. elongata . This could involve utilizing 28S D1-D2, known for its ability to distinguish between Hymeraphia species ( Morrow et al. 2018), and incorporating sequences from the type specimen or specimens from the type locality.